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UGO MARIA PAGNONI

Professore emerito
Dipartimento di Scienze della Vita sede ex-Chimica

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Pubblicazioni

2009 - Bioconversion of soy isoflavones daidzin and daidzein by Bifidobacterium strains. [Articolo su rivista]
Raimondi, Stefano; Roncaglia, Lucia; M., De Lucia; Amaretti, Alberto; Leonardi, Alan; Pagnoni, Ugo Maria; Rossi, Maddalena
abstract

Twenty-two strains of Bifidobacterium, representative of eight major species of human origin, were screened for their ability to transform the isoflavones daidzin and daidzein. Most of the strains released the aglycone from daidzin and 12 gave yields higher than 90%. The kinetics of growth, daidzin consumption, and daidzein production indicated that the hydrolytic activity occurred during the growth. The supernatant of the majority of the strains did not release the aglycone from daidzin, suggesting that cell-associated beta-glucosidases (beta-Glu) are mainly responsible for the metabolism of soybean glyco-conjugates. Cell-associated beta-Glu was mainly intracellular and significantly varied among the species and the strains. The lack of beta-Glu was correlated with the inability to hydrolyze daidzin. Although S-equol production by anaerobic intestinal bacteria has been established, information on S-equol-producing bifidobacteria is contradictory. In this study, 22 bifidobacteria failed to transform daidzein into reduced metabolites under all the experimental conditions, excluding any role in the reductive pathway of daidzein toward the production of S-equol. These results suggest that selected probiotic strains of Bifidobacterium can be used to speed up the release of daidzein, improving its bioavailability for absorption by colonic mucosa and/or biotransformation to S-equol by other intestinal microorganisms.

2009 - Growth, lipid accumulation, and fatty acid composition in obligate psychrophilic, facultative psychrophilic, and mesophilic yeasts. [Articolo su rivista]
Rossi, Maddalena; P., Buzzini; L., Cordisco; Amaretti, Alberto; M., Sala; Raimondi, Stefano; C., Ponzoni; Pagnoni, Ugo Maria; D., Matteuzzi
abstract

Obligate psychrophilic, facultative psychrophilic, and mesophilic yeasts were cultured in a carbon-rich medium at different temperatures to investigate whether growth parameters, lipid accumulation, and fatty acid (FA) composition were adaptive and/or acclimatory responses. Acclimation of facultative psychrophiles and mesophiles to a lower temperature decreased their specific growth rate, but did not affect their biomass yield (Y(X/S)). Obligate and facultative psychrophiles exhibited the highest Y(X/S). Acclimation to lower temperature decreased the lipid yield (Y(L/X)) in mesophilic yeasts, but did not affect Y(L/X) in facultative psychrophilic ones. Similar Y(L/X) were found in both groups of psychrophiles, suggesting that lipid accumulation is not a distinctive characteristic of adaptation to permanently cold environments. The unsaturation of FAs was one major adaptive feature of the yeasts colonizing permanently cold ecosystems. Remarkable amounts of alpha-linolenic acid were found in obligate psychrophiles at the expense of linoleic acid, whereas it was scarce or absent in all the other strains. Increased unsaturation of FAs was also a general acclimatory response of facultative psychrophiles to a lower temperature. These results improve the knowledge of the responses enabling psychrophilic yeasts to cope with the cold and may be of support for potential biotechnological exploitation of these strains.

2009 - Synthesis of the disubstituted maleic anhydride frame using a novel tandem radical-polar reaction [Articolo su rivista]
Pattarozzi, Mariella; Ghelfi, Franco; Roncaglia, Fabrizio; Pagnoni, Ugo Maria; A. F., Parsons
abstract

An unreported 5-endo-trig atom transfer radical cyclization of cyclic N--dichloroacyl-ketene-N,S-acetals, which evolves as a tandem radical-polar process, is described. The reaction, which is carried out in the presence of a Cu(I) complex catalyst (10 mol%) and an inorganic base (i.e. carbonate), can be exploited as the key step for a novel, short and versatile synthesis of the 3,4-disubstituted maleic anhydride nucleus.

2008 - Biotransformation of Acyclic Monoterpenoids by Debaryomyces sp., Kluyveromyces sp. and Pichia sp. Strains of Environmental Origin [Articolo su rivista]
Ponzoni, Chiara; C., Gasparetti; M., Goretti; B., Turchetti; Pagnoni, Ugo Maria; Cramarossa, Maria Rita; Forti, Luca; P., Buzzini
abstract

Sixty yeast strains, which belong to 32 species of the genera Debaryomyces, Kluyveromyces and Pichia, and which were isolated from plant-, soil- or insect-associated habitats, were screened for their ability to biotransform the acyclic monoterpenes geraniol and nerol. The aptitude to convert both compounds (from 2.6 to 30.6 and from 2.7 to 29.1 %/g cell DW, = dry weight), resp.) was apparently a broad distributed character in such yeasts. Depending upon the substrate used, the production of linalool, alfa-terpineol, β-myrcene, D-limonene, (E)-β-ocimene, (Z)-β-ocimene or carene was observed. Linalool was the main product obtained from geraniol, whereas linalool and alfa-terpineol were the main products obtained through the conversion of nerol. Yet, differently from nerol, the aptitude to exhibit high bioconversion yields of geraniol to linalool was an apparently genus-related character, whereas the ability to produce other monoterpenes was a both genus- and habitat-related character. The possible pathways of bioconversion of geraniol or nerol to their derivative were proposed/discussed.

2008 - Characterization of the superoxide dismutase SOD1 gene of Kluyveromyces marxianus L3 and improved production of SOD activity [Articolo su rivista]
Raimondi, Stefano; Uccelletti, D; Matteuzzi, D; Pagnoni, Ugo Maria; Rossi, Maddalena; Palleschi, C.
abstract

Superoxide dismutase (SOD) activity is one major defense line against oxidative stress for all of the aerobic organisms, and industrial production of this enzyme is highly demanded. The Cu/Zn superoxide dismutase gene (KmSOD1) of Kluyveromyces marxianus L3 was cloned and characterized. The deduced KmSod1p protein shares 86% and 71% of identity with Kluyveromyces lactis and Saccharomyces cerevisiae Sod1p, respectively. The characteristic motifs and the amino acid residues involved in coordinating copper and zinc and in enzymatic function were conserved. To the aim of developing a microbial production of Cu/Zn superoxide dismutase, we engineered the K. marxianus L3 strain with the multicopy plasmid YG-KmSOD1 harboring the KmSOD1 gene. The production of KmSOD1p in K. marxianus L3 and K. marxianus L3 (pYG-KmSOD1) in response to different compositions of the culture medium was evaluated. The highest specific activity (472 U(SOD) mg(prot) (-1)) and the highest volumetric yield (8.8 x 10(5) U(SOD) l(-1)) were obtained by the recombinant strain overexpressing KmSOD1 in the presence of Cu(2+) and Zn(2+) supplements to the culture media. The best performing culture conditions were positively applied to a laboratory scale fed-batch process reaching a volumetric yield of 1.4 x 10(6) U(SOD) l(-1).

2008 - In vitro comparison of the prebiotic effects of two inulin-type fructans [Articolo su rivista]
Pompei, A; Cordisco, L; Raimondi, Stefano; Amaretti, Alberto; Pagnoni, Ugo Maria; Matteuzzi, D; Rossi, Maddalena
abstract

Faecal cultures were used to compare the prebiotic effects of a new fructan containing high solubility inulin (HSI) and of a well-established prebiotic containing oligofructose (OF) with a negative control (CT). Changes in the intestinal microbiota, pH, ammonia, volatile organic acids and lactic acid were monitored during incubation. Molecular techniques for microbial enumeration indicated that both HSI and OF led to a significant increase in bifidobacteria (P≤0.05) and lactobacilli (P≤0.05) compared to the control. Significant changes in the pH and levels of ammonia with both inulin-type fructans were observed, as well as higher levels of acetic, lactic and formic acids (P≤0.05). The fermentative metabolism appeared to be faster on OF than on HSI. Both OF and HSI showed clear prebiotic effects, but had differences in fermentation kinetics because of to the different degree of polymerization (DP). This study provides proof for the prebiotic effectiveness of HSI, and shows that inulin-type fructans with higher DP might have a prolonged bifidogenic effect, thus could extend the saccharolytic metabolism and low pH to the distal parts of the colon.

2008 - Preparation of the Maleic Anhydride Nucleus from Dichloro γ-Lactams: Focus on the Role of the N-Substituent in the Functional Rearrangement and in the Hydrolytic Steps [Articolo su rivista]
Ghelfi, Franco; M., Pattarozzi; Roncaglia, Fabrizio; A. F., Parsons; F., Felluga; Pagnoni, Ugo Maria; E., Valentin; Mucci, Adele; Bellesia, Franco
abstract

The preparation of the 3,4-dialkyl-substituted maleic anhydride nucleus, through the functional rearrangement of dichloro γ-lactams, allowed the comparison of various N-substituents in the functional rearrangement step. The 2-pyridyl group proved to be the most appropriate N-substituent for the hydrolysis of the 5-methoxy-1,5-dihydro-2H-pyrrol-2-one intermediate into the 5-hydroxy adduct, and for the hydrolysis of the maleimide nucleus into the maleic anhydride. The oxidation of the 5-hydroxy-1,5-dihydro-2H-pyrrol-2-one into the corresponding maleimide was achieved with manganese(IV) oxide.

2007 - A novel short approach to (Z)-pulchellalactam through Transition-Metal-Catalized Atom-Transfer Radical Cyclization of 1-isopropylprop-2-enyl dichloroacetate [Articolo su rivista]
F., Felluga; Ghelfi, Franco; Pagnoni, Ugo Maria; Af, Parsons; M., Pattarozzi; Roncaglia, Fabrizio; E., Valentin
abstract

A new five-step route to the CD45 protein tyrosine phosphatase inhibitor (Z)-pulchellalactam is presented. Key steps are the CuCl-bipyridine catalysed atom transfer radical cyclization of an appropriate allyl ,-dichloroacetate and the subsequent dehydrochlorination/prototropic rearrangement of the resulting dichlorolactone.

2007 - Atom Tranfer Radical Cyclization (ATRC) applied to a chemo-enzymatic synthesis of Quercus Lactones [Articolo su rivista]
Felluga, F; Forzato, C; Ghelfi, Franco; Nitti, P; Pitacco, G; Pagnoni, Ugo Maria; Roncaglia, Fabrizio
abstract

The natural fragrances (+)-trans whisky lactone 2 and (+)-trans cognac lactone 4, together with a minor amount of their ()-cis stereoisomers, were prepared in 50% and 42% overall yield, respectively, starting from racemic 1-hepten-3-ol (±)-5 and 1-octen-3-ol(±)-6. The procedure involved first the enantioconvergent, lipase mediated transformation of the secondary allylic alcohols deriveddichloroacetates (±)-7 and (±)-8 into the corresponding homochiral (+)-7 and (+)-8, combined with their cyclization under a transitionmetal catalyzed atom transfer process.

2007 - Laccase catalyzed dimerization of hydroxystilbenes [Articolo su rivista]
Ponzoni, Chiara; E., Beneventi; Cramarossa, Maria Rita; Raimondi, Stefano; G., Trevisi; Pagnoni, Ugo Maria; S., Riva; Forti, Luca
abstract

A series of hydroxystilbenes, analogues of the bioactive phytoalexin resveratrol, were synthesized and submitted to the catalytic action of a laccase from Trametes pubescens in a biphasic system made of ethyl acetate and acetate buffer. Oxidation took place at the 4’-hydroxy (4-hydroxy) position ofthe hydroxystilbenicm oieties, followed by radicalradicalcoupling dimerization reactions. Most of the products were isolated in good yields and fully characterized.Depending on the substrates, three different dimeric products could be identified, the main products usually being 4-O-a-ß-5 (dihydrofuran-like) dimers.

2006 - A new and effective route to (+/-)-botryodiplodin and (+/-)-epi-botryodiplodin acetates using a halogen atom transfer Ueno-Stork cyclization [Articolo su rivista]
L., DE BUYCK; C., Forzato; Ghelfi, Franco; Mucci, Adele; P., Nitti; Pagnoni, Ugo Maria; Af, Parsons; G., Pitacco; Roncaglia, Fabrizio
abstract

(+/-)-Botryodiplodin and (+/-)-epi-botryodiplodin acetates were prepared in good yields following a practical four step route. The method, for the construction of the strategic tetrahydrofuran ring, hinged on an unprecedented halogen atom transfer Ueno-Stork cyclization of an O-allyl alpha,alpha-dihalohemiacetal acetate, catalyzed by the redox complex CuCl/N,N,N ',N '',N ''-pentamethyldiethylenetriamine. (c) 2006 Elsevier Ltd. All rights reserved.

2006 - A short approach to chaetomellic anhydride A from2,2-dichloropalmitic acid: elucidation of the mechanism governingthe functional rearrangement of the chlorinatedpyrrolidin-2-one intermediate [Articolo su rivista]
Bellesia, Franco; Danieli, Chiara; L., De Buyck; R., Galeazzi; Ghelfi, Franco; Mucci, Adele; M., Orena; Pagnoni, Ugo Maria; A. F., Parsons; Roncaglia, Fabrizio
abstract

Chaetomellic anhydride A was efficiently attained in three steps, starting from 2,2-dichloropalmitic acid and 2-(3-chloro-2-propenylamino)pyridine. Atom transfer radical cyclisation selectively formed the cis-stereoisomer of the trichloropyrrolidin-2-one, which underwent a stereospecific functional rearrangement to form a substituted maleimide. The choice of 2-pyridyl, as ‘cyclisation auxiliary’ in the atom transfer radical cyclisation step, proved beneficial for hydrolysis of the maleimide to form the desired anhydride.

2006 - Application of the response surface methodology (RSM) for optimizing the production of volatile organic compounds (VOCs) by Trichosporon moniliiforme [Articolo su rivista]
C., Gasparetti; P., Buzzini; Cramarossa, Maria Rita; B., Turchetti; Pagnoni, Ugo Maria; Forti, Luca
abstract

Response surface methodology (RSM) was applied in optimizing the production of volatile organic compounds (VOCs) by shake-flask cultures of a selected Trichosporon moniliiforme strain (DBVPG 4665). A factorial experiment (2(3)) was designed by setting three parameters at two levels: X-1 = incubation time (IT = 72-168 h); X-2 = pH (4-7); X-3 = L-methionine concentration (L-MET = 5-20 g l(-1)). On the basis of the results of factorial design, X-2 (pH) and X-3 (L-MET) were optimized by performing a central composite design (CCD). Second-order polynomial models and response surfaces were obtained for total VOC concentration (VOC1) and for the percentage of dimethyl disulphide (DMDS)/total VOCs (%DMDS). A range of variation of X-2 and X-3 able to maximize simultaneously both responses has been found. Average final values of responses (VOC1 = 4.9 +/- 1.3 mg l(-1); %DMDS = 97.6 +/- 1.1%) were about 532 and 133% of data of central point and were in good agreement with calculated values, thus confirming the reliability of our empirical model in optimizing VOCs production by T. moniliiforme (c) 2006 Elsevier Inc. All rights reserved.

2005 - A key process of aroma evolution: fatty acid beta-oxidation in Parmesan cheese ripening [Articolo su rivista]
Bellesia, Franco; A., Pinetti; Pagnoni, Ugo Maria; Zucchi, Claudia; L., Caglioti; G., Palyi
abstract

Methylketones and short chain fatty acids constitute the main part of the compounds responsible of the aroma evolution in cheese processing, mainly during ripening. An insight into the fatty acid degradation patterns shows that a maximum enzymic activity is likely to occur up to the formation of n-hexanoic acid and 2-heptanone, which are released in higher amounts with respect to both longer and shorter chain analogues. An evolution trend of the investigated volatile organic compounds (VOCs) might be correlated to the Parmesan Cheese ageing.

2005 - A new route to (±)-erythro-roccellic acid and chaetomellic anhydride C through functional rearrangement, promoted by n-propylamine or CH3ONa/CH3OH, of N-propyl-3-chloro-4-dichloromethyl-3-dodecylpyrrolidin-2-one [Articolo su rivista]
L., De Buyck; Danieli, Chiara; Ghelfi, Franco; Pagnoni, Ugo Maria; Af, Parsons; Pattarozzi, Mariella; Roncaglia, Fabrizio
abstract

The rearrangement of a trichloro-pyrrolidin-2-one, prepared by the CuCl-TMEDA catalyzed atom transfer radical cyclization of N-alkyl-N-(3-chloro-2-propenyl)-2,2-dichloromyristamide, with n-propylamine or CH3ONa/CH3OH, is the key step of a new, short and inexpensive route to chaetomellic anhydride C and (+/-)-erythro-roccellic acid.

2005 - Biocatalytic reduction of (+)- and (–)-carvone by bacteria [Articolo su rivista]
Cramarossa, Maria Rita; A., Nadini; Bondi, Moreno; Messi, Patrizia; Pagnoni, Ugo Maria; Forti, Luca
abstract

The biotransformation of the two enantiomers of carvone, (–)-(1a) and (+)-(1b), by two bacteria (Pseudomonas putida and Acinetobacter lwoffi) isolated from different environments is reported. The metabolites from the biotransformations carried out in liquid cultures using the sterile TS-2 mineral medium were screened by headspace solid phase microextraction/GC–MS. The results show that these bacteria are efficient tools in the diastereoselective bioreduction of (+)- and (–)-carvone.

2005 - Nuova sintesi della (+/-)-Botriodiplodina attraverso ciclizzazione di Ueno-Stork a trasferimento di atomo [Abstract in Atti di Convegno]
Roncaglia, Fabrizio; L., De Buyck; Bellesia, Franco; C., Forzato; Ghelfi, Franco; L., Goldoni; Mucci, Adele; Pagnoni, Ugo Maria; A. F., Parsons; E., Valentin
abstract

E' presentata una nuova sintesi della (+/-)-Botriodiplodina attraverso ciclizzazione di Ueno-Stork a trasferimento di atomo

2005 - Production of volatile organic compounds (VOCs) by yeasts isolated from the ascocarps of black (Tuber melanosporum Vitt.) and white (Tuber magnatum Pico) truffles [Articolo su rivista]
P., Buzzini; C., Gasparetti; B., Turchetti; Cramarossa, Maria Rita; A., Vaughan Martini; A., Martini; Pagnoni, Ugo Maria; Forti, Luca
abstract

Twenty-nine yeast strains were isolated from the ascocarps of black and white truffles (Tuber melanosporum Vitt. and Tuber magnatum Pico, respectively), and identified using a polyphasic approach. According to the conventional taxonomic methods, MSP-PCR fingerprinting and sequencing of the D1/D2 domain of 26S rDNA, the strains were identified as Candida saitoana, Debaryomyces hansenii, Cryptococcus sp., Rhodotorula mucilaginosa, and Trichosporon moniliiforme. All isolates assimilated L-methionine as a sole nitrogen source and produced the volatile organic compounds (VOCs), 2-methyl butanol, 3-methyl butanol, methanethiol, S-methyl thioacetate, dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, dihydro-2-methyl-3(2H)-thiophenone and 3-(methylthio)-1-propanol (MTP). ANOVA analysis of data showed significant (P < 0.01) differences in VOCs produced by different yeasts, with MTP as the major component (produced at concentrations ranging from 19.8 to 225.6 mg/l). In addition, since some molecules produced by the isolates of this study are also characteristic of truffle complex aroma, it is possible to hypothesize a complementary role of yeasts associated with this ecosystem in contributing to final Tuber spp. aroma through the independent synthesis of yeast-specific volatile constituents.

2005 - Sintesi della (+/-)-Botriodiplodina e della sua forma Epi attraverso una ciclizzazione di Ueno-Stork a trasferimento di atomo [Abstract in Atti di Convegno]
Roncaglia, Fabrizio; L., De Buyck; Bellesia, Franco; C., Forzato; Ghelfi, Franco; L., Goldoni; Mucci, Adele; Pagnoni, Ugo Maria; A. F., Parsons; E., Valentin
abstract

E' riportata la sintesi della (+/-)-botriodiplodina e della sua forma Epi attraverso una ciclizzazione di Ueno-Stork a trasferimento di atomo

2005 - Studio di una via più versatile per la preparazione di nuclei 2,5-furandionici disostituiti [Abstract in Atti di Convegno]
L., De Buyck; Ghelfi, Franco; Mucci, Adele; Pagnoni, Ugo Maria; A. F., Parsons; Pinetti, Adriano; Roncaglia, Fabrizio
abstract

Si riporta lo studio di una via più versatile per la preparazione di nuclei 2,5-furandionici disostituiti

2004 - A simple and efficient route to chaetomellic anhydride A: A potent natural Ras farnesyl-protein transferase inhibitor [Articolo su rivista]
L., De Buyck; Cagnoli, Rita; Ghelfi, Franco; G., Merighi; Mucci, Adele; Pagnoni, Ugo Maria; A. F., Parsons
abstract

A new and efficient approach to chaetomellic anhydride A has been devised starting from 2,2-dichloropalmitic acid. This involves the atom transfer radical cyclization of an N-alkyl-N-(3-chloro-2-propenyl)amide followed by rearrangement of the resulting trichloro-pyrrolidin-2-one.

2004 - Biotransformation of resveratrol: synthesis of trans-dehydrodimers catalyzed by laccases from Myceliophtora thermophyla and from Trametes pubescens [Articolo su rivista]
S., Nicotra; Cramarossa, Maria Rita; Mucci, Adele; Pagnoni, Ugo Maria; S., Riva; Forti, Luca
abstract

Laccases from different sources have been used, for the first time, for the selective oxidation of the stilbenic phytoalexin transresveratrol (3,5,4´-trihydroxystilbene, 1a) on a preparative scale. Specifically, the enzymes from Myceliophtora thermophyla and from Trametes pubescens gave the dehydrodimer 2a in 31 and 18% isolated yields, respectively. These results compare favorably with the reported data for the chemically catalyzed dimerization of la (18% yields). The antioxidant properties of 2a have also been investigated.

2004 - Functional rearrangement of polychlorinated pyrrolidin-2-onesto 5-imino-lactams promoted by n-propylamine [Articolo su rivista]
Danieli, Chiara; Ghelfi, Franco; Mucci, Adele; Pagnoni, Ugo Maria; A. F., Parsons; M., Pattarozzi; Schenetti, Luisa
abstract

Abstract—The reaction of 4-methyl-pyrrolidin-2-ones, chlorinated at the C(3) and C(6) positions, with n-propylamine constitutes a new method for the preparation of 5-propylimino-pyrrolidin-2-ones or 3-pyrrolin-2-ones in generally good yields. The transformation involves a series of eliminations, substitutions and double bond shifts. This constitutes a remarkable example of a functional rearrangement.

2004 - Oxidation of aliphatic 2,2-dichloroalkanals by HNO3 in CH2Cl2: An easy and eco-friendly route to the corresponding 2,2-dichloroalkanoic acids [Articolo su rivista]
Bellesia, Franco; L., De Buyck; Ghelfi, Franco; Pagnoni, Ugo Maria; P., Strazzolini
abstract

A simple, economically convenient, and eco-compatible procedure for the oxidation of 2,2-dichloroalkanals to the corresponding alkanoic acids has been set up, employing HNO3 in CH2Cl2, in the presence of NaNO2 as catalyst.

2004 - Produzione di aromi e fragranze da impiegarsi in campo alimentare mediante biodegradazioni microbiche di terpeni [Relazione in Atti di Convegno]
Bondi, Moreno; Cramarossa, Maria Rita; Forti, Luca; A., Nadini; Pagnoni, Ugo Maria; Messi, Patrizia
abstract

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2004 - Sintesi dell’acido chetomellico A, un antitumorale naturale inibitore della RAS farnesil-protein transferasi (FPTasi) [Abstract in Atti di Convegno]
L., De Buyck; Danieli, Chiara; Ghelfi, Franco; Mucci, Adele; Pagnoni, Ugo Maria; Pinetti, Adriano; A. F., Parsons
abstract

Si propone una nuova via sintetica per l'ottenimento dell’acido chetomellico A.

2004 - Synthetic utility of 2,2-dichlorocarboxylic acids [Abstract in Atti di Convegno]
L., De Buyck; Ghelfi, Franco; Mucci, Adele; Pagnoni, Ugo Maria; N., Dieltiens; A. F., Parsons
abstract

The synthetic utility of derivatives of 2,2-dichlorocarboxylic acids in radical cyclization reactions is shown.

2003 - An efficient route to aliphatic 2,2-dichloroaldehydes via chlorination of aldehydes or alcohols with the system Cl-2/quaternary ammonium chloride [Articolo su rivista]
Bellesia, Franco; L., De Buyck; Ghelfi, Franco; Pagnoni, Ugo Maria; Af, Parsons; Pinetti, Adriano
abstract

An effective and low waste method for preparing aliphatic 2,2-dichloroaldehydes has been achieved by halogenation of aldehydes or alcohols with Cl-2, using tetraalkylammonium chlorides as recoverable catalysts.

2003 - Biodegradazioni microbiche di terpeni per la produzione di aromi e fragranze [Relazione in Atti di Convegno]
Bondi, Moreno; Cramarossa, Maria Rita; Forti, Luca; Nadini, A; Pagnoni, Ugo Maria; Messi, Patrizia
abstract

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2003 - Biotrasformazioni di terpeni mediate da batteri ambientali [Abstract in Atti di Convegno]
Bondi, Moreno; Cramarossa, Maria Rita; Forti, Luca; Messi, Patrizia; A., Nadini; Pagnoni, Ugo Maria
abstract

Negli ultimi anni si è avuto un incremento della produzione biotecnologica di aromi chimici naturali (NACs) legato alla richiesta, da parte dei consumatori, di prodotti biologici. L’interesse per gli aromi naturali rispetto a quelli ottenuti per sintesi chimica ha comportato un aumento della produzione “microbica” di bioaromi. Un aroma per essere definito “naturale” deve essere ottenuto da sostanze naturali attraverso trasformazioni biocatalitiche che utilizzino enzimi o microrganismi ed il prodotto finale deve essere identico ad una sostanza nota già presente in natura. Se lo stesso prodotto è ottenuto per sintesi chimica si può classificare come “natural identic”. I terpenoidi sono precursori naturali poco costosi, facilmente reperibili e rinnovabili e costituiscono il maggior gruppo di prodotti naturali con piu’ di 22.000 strutture conosciute. I monoterpeni, che sono ampiamente distribuiti in natura e sono fra i componenti principali degli olii essenziali di erbe, spezie e conifere, costituiscono una classe di substrati precursori molto utili e, dato il loro utilizzo nell’industria profumiera ed alimentare, sono prodotti di partenza ideali per la produzione biotecnologica di NACs.Sono note in letteratura diverse bioconversioni di monoterpeni per la produzione di aromi naturali con vari microorganismi, in particolare funghi e lieviti, mentre sono state meno sudiate le bioconversioni con batteri. In questo lavoro sono riportate le biotrasformazioni di citrale e carvone biocatalizzate da alcuni batteri ambientali: Pseudomonas putida, Pseudomonas aeruginosa, Pseudomonas cepacia, Pseudomonas fluorescens, Acinetobacter lwoffi e Flavobacterium spp. In tutte le bioconversioni le uniche fonti di carbonio e di energia sono rappresentate dai monoterpeni. Pseudomonas putida riduce selettivamente il carvone a diidrocarvone, mentre Acinetobacter lwoffi, Flavobacterium spp. e Pseudomonas aeruginosa sono in grado di ridurre ulteriormente il prodotto a diidrocarveolo. Non vi è alcuna bioconversione né con la Pseudomonas cepacia nè con la Pseudomonas fluorescens. La citrale (miscela di nerale e geraniale) è ridotta a nerolo e geraniolo da Acinetobacter lwoffi mentre con Pseudomonas putida si ha un’ulteriore riduzione a citronellolo. La bioconversione con Flavobacterium spp è caratterizzata da un cammino riduttivo, che porta dapprima alla formazione di nerolo e geraniolo e successivamente a citronellolo, e da un cammino degradativo, in cui si ottiene il 6-metil-5-epten-2-one (un prodotto lineare di degradazione dei terpeni) nelle prime 24 ore e successivamente CO2 ed H2O. Lo stesso cammino degradativo si ha anche con Pseudomonas cepacia, con Pseudomonas fluorescens e con Pseudomonas aeruginosa.

2003 - Glutaryl acylases: One-reaction enzymes or versatile enantioselective biocatalysts? [Articolo su rivista]
Raimondi, S.; Monti, D.; Pagnoni, Ugo Maria; Riva, S.
abstract

A significant broad substrate specificity, that crosses over the usual beta-lactam derivatives, has been observed with an industrial glutaryl-7-aminocephalosporanic acid acylase (GA). This enzyme possesses significant enantioselective amidase and even esterase activity, with a stereopreference for the S-enantiomer. The easy separation of products from unreacted reagents, possessing different physical-chemical properties, is achieved by solvent extraction, avoiding chromatography or distillation during reaction work-up.

2003 - Hydro-de-halogenation and consecutive deprotection of chlorinated N-amido-pyrrolidin-2-ones with Raney-Ni: an effective approach to gabapentin [Articolo su rivista]
R., Cagnoli; Ghelfi, Franco; Pagnoni, Ugo Maria; Af, Parsons; Schenetti, Luisa
abstract

The benzoylamino group was identified as a useful radical cyclization auxiliary that can be smoothly removed on hydro-dehalogenation of chlorinated N-substituted-pyrrolidin-2-ones with Raney-Ni. This methodology was successfully implemented in a new and appealing route to the anti-epileptic drug gabapentin.

2003 - Sintesi semplificata dell’acido chetomellico A, antitumorale naturale inibitore della Ras farnesil-protein transferasi [Abstract in Atti di Convegno]
L., De Buyck; Bellesia, Franco; Ghelfi, Franco; G., Merighi; Mucci, Adele; Pagnoni, Ugo Maria; Pinetti, Adriano; A. F., Parsons
abstract

E' riportata una sintesi semplificata dell’acido chetomellico A, antitumorale naturale inibitore della Ras farnesil-protein transferasi.

2003 - Synthesis of 5-methoxylated 3-pyrrolin-2-one via the rearrangement of chlorinated pyrrolidin-2-ones [Articolo su rivista]
Ghelfi, Franco; Cv, Stevens; I., Laureyn; E., Van Meenen; Tm, Rogge; L., De Buyck; K. V., Nikitin; Grandi, Romano; Libertini, Emanuela; Pagnoni, Ugo Maria; Schenetti, Luisa
abstract

The reaction of N-substituted 4-methyl-2-pyrrolidinones or 4-diethoxyphosphoryl analogues, carrying at least two chlorine atoms between the C(3) and C(6) carbons, with alkaline methoxide in methanol afforded the corresponding 5-methoxylated 3-pyrrolin-2-ones, useful adducts for the preparation of agrochemicals or medicinal compounds. (C) 2003 Elsevier Science Ltd. All rights reserved.

2003 - Volatile components of Grana Parmigiano-Reggiano type hard cheese [Articolo su rivista]
Bellesia, Franco; Pinetti, Adriano; Pagnoni, Ugo Maria; R., Rinaldi; C., Zucchi; L., Caglioti; Palyi, Gyula
abstract

GC-MS analysis of volatile components of Grana Parmigiano-Reggiano type Italian hard cheese was performed by solid phase micro extraction (SPME) and Purge & Trap (PT) methods. Half of the 24 samples analysed were produced in flat land ( < 90 in over sea level), the other half in mountain (90-600 in) regions, by small to medium cheese factories. The composition of the volatile components reveals more dependence on the individual factories than on the geographic location. Ripening increases the difference among samples.

2002 - 1,2-reduction of alpha,beta-unsaturated hydrazones using dimethylamine-borane/p-toluenesulfonic acid: an easy route to allyl hydrazines [Articolo su rivista]
M. E., Casarini; Ghelfi, Franco; Libertini, Emanuela; Pagnoni, Ugo Maria; A. F., Parsons
abstract

alpha,beta-Unsaturated hydrazones can be easily converted into N-allyl hydrazines by reaction with dimethylamine-borane/p-toluenesulfonic acid under mild reaction conditions. The reduction works well for N'-allyhydrazides but N'-allyl-N,N-dimethylhydrazines are rapidly reoxidised by air and so need to be manipulated under an inert atmosphere prior to M-acylation. Competitive conjugate reduction can also be observed and the regioselectivity of the dimethylamine-borane attack is determined by steric and/or electronic factors. The procedure is also effective for the C=N reduction of unconjugated hydrazones. (C) 2002 Elsevier Science Ltd. All rights reserved.

2001 - Cyclization of citronellal to menthone and isomenthone catalyzed by Al/Fe-Pillared Clays [Articolo su rivista]
Cramarossa, Maria Rita; Forti, Luca; Pagnoni, Ugo Maria; M., Vidali
abstract

The cyclization of citronellal to a mixture of menthone and isomenthone (2:1) is catalyzed by Al/Fe-Pillared Clay (Al/Fe-PILC) at 80 degreesC in 1,2-dichloroethane in good yield. At room temperature the products are isopulegol and neo-isopulegol, the isomer ratio depending on the reaction conditions.

2001 - Specific structural determinants are responsible for the antioxidant activity and the cell cycle effects of resveratrol [Articolo su rivista]
L. A., Stivala; M., Savio; F., Carafoli; P., Perucca; L., Bianchi; G., Maga; Forti, Luca; Pagnoni, Ugo Maria; A., Albini; E., Prosperi; V., Vannini
abstract

Resveratrol (3,4',5-trihydroxy-trans-stilbene) is a natural phytoalexin found in grapes and wine, which shows antioxidant and antiproliferative activities. In this study we have investigated whether these properties are dependent on similar or different structural determinants of the molecule. To this purpose, resveratrol derivatives, in which all or each single hydroxylic function were selectively substituted with methyl groups, were synthesized. Analogues with the stilbenic double bond reduced or with the stereoisomery modified were also investigated. The antioxidant activity of these compounds was evaluated by measuring the inhibition of citronellal thermo-oxidation, or the reduction of 2,2 diphenyl-1-picrylhydrazyl radical. In addition, the protection against lipid peroxidation was determined in rat liver microsomes, and in human primary cell cultures. The antiproliferative activity was evaluated by a clonogenic assay, and by analysis of cell cycle progression and DNA synthesis. The results showed that the hydroxyl group in 4' position is not the sole determinant for antioxidant activity. In contrast, the presence of 4'-OH together with stereoisomery in the trans conformation (4'-hydroxystyryl moiety) was absolutely required for inhibition of cell proliferation. Enzymatic assays in vitro demonstrated that inhibition of DNA synthesis was induced by a direct interaction of resveratrol with DNA polymerases alpha and delta.

2001 - Unusual access to 5-methoxy or 5,5-dimethoxy-4-methyl-3-pyrrolin-2-ones from chlorinated 4-methyl-pyrrolidin-2-ones [Articolo su rivista]
Bellesia, Franco; L., DE BUYCK; M. V., Colucci; Ghelfi, Franco; I., Laureyn; Libertini, Emanuela; Mucci, Adele; Pagnoni, Ugo Maria; Pinetti, Adriano; T. M., Rogge; C. V., Stevens
abstract

The reaction of N-substituted 4-methyl-2-pyrrolidinones, carrying not less than two chlorine atoms on the C(3) and C(6) carbons afforded with alkaline methoxide in methanol, under mild conditions, the corresponding 5-methoxy or 5,5-dimethoxy-4-methyl-3-pyrrolin-2-ones in satisfactory yields.

2000 - 2,2-dichlorination of aldehydes with the 2,6-lutidine center dot HCl/Cl-2/CH2Cl2 system: An environmentally benign process suitable for scale up [Articolo su rivista]
Bellesia, Franco; L., De Buyck; Ghelfi, Franco; Libertini, Emanuela; Pagnoni, Ugo Maria; Roncaglia, Fabrizio
abstract

An effective and environmentally benign preparation of 2,2-dichloroaldehydes has been achieved by chlorination of aldehydes with Cl-2(g) in CH2Cl2, using 2,6-lutidine hydrochloride as recoverable catalyst. Remarkable qualities of the process are: easy work up, high purity products, HCl as the only 'waste' stream and inherent bias to the scale up. (C) 2000 Elsevier Science Ltd. All rights reserved.

1999 - Conformationally constrained amino acids: A convenient approach to cis-2,3-methano-GABAs [Articolo su rivista]
Forti, Luca; Ghelfi, Franco; S., Levizzani; Pagnoni, Ugo Maria
abstract

3-Aza-2-oxo-bicyclo[3.1.0]hexanes, which are opened to 2,3-methano-gamma-aminobutyric acids, are obtained in very high yields by a two step procedure from N-protected-N-allyl-alpha-Br-amides. (C) 1999 Elsevier Science Ltd. All rights reserved.

1999 - Easy approach to 3-benzylimino-2-pyrrolidinones from 3-chloro-4-chloromethyl-2-pyrrolidinones [Articolo su rivista]
Ghelfi, Franco; G., Ghirardini; Libertini, Emanuela; Forti, Luca; Pagnoni, Ugo Maria
abstract

3-Benzylimino-2-pyrrolidinones can be prepared in good yield by heating 3-chloro-4-chloromethyl-2-pyrrolidinones, benzylamine and NaI in THF at 80 degrees C. An endo-dehydrohalogenation followed by a SN2' substitution on the intermediate allyl chloride, and finally a shift of the exo-double bond to Delta(3) with attendant tautomerization, appears to be the most probable reaction mechanism. (C) 1999 Elsevier Science Ltd. All rights reserved.

1999 - Rearrangement of N-allyl-alpha,alpha-dichloroamides, beta- or gamma-functionalized, to substituted analogues of the gamma-aminobutyric acid (GABA) [Articolo su rivista]
Bellesia, Franco; Forti, Luca; Ghelfi, Franco; G., Ghirardini; Libertini, Emanuela; Pagnoni, Ugo Maria; Pinetti, Adriano; N., Prochilo
abstract

The rearrangement of gamma-chloro, beta-hydroxy or beta-vinyl N-allyl-N-benzyl-alpha,alpha-dichlorocarboxyamides to gamma-aminobutyric acid analogues is efficiently promoted by CuCl\N,N,N',N'-tetramethylethylendiamine. With the beta-vinyl functionalization a tandem radical-radical reaction, yielding 3-aza-2-oxo-bicyclo[3,3,0]octane adducts, is also observed.

1999 - The influence of benzylic protection and allylic substituents on the CuCl-TMEDA catalyzed rearrangement of N-allyl-N-benzyl-2,2-dihaloamides to gamma-lactams. Application to the stereoselective synthesis of pilolactam. [Articolo su rivista]
Ghelfi, Franco; Bellesia, Franco; Forti, Luca; G., Ghirardini; Grandi, Romano; Libertini, Emanuela; M. C., Montemaggi; Pagnoni, Ugo Maria; Pinetti, Adriano; L., De Buyck; A. F., Parson
abstract

A number of N-benzylic protecting groups and allylic substituents have been investigated for the rearrangement, promoted by CuCl-TMEDA, of N-allyl-2,2-dihaloamides to 3,4-disubstituted gamma-lactams. An appreciable chiral induction was observed at the C-4 site when alpha-phenylethylamine was used as a chiral protecting group, while an unexpected Diels-Alder reaction occurred when using a 2-furyl-methyl protection. This rearrangement has been applied to the synthesis of pilolactam, a drug with muscarinic activity. (C) 1999 Elsevier Science Ltd. All rights reserved.

1998 - Telechelic oligomers by halogen atom transfer radical addition [Articolo su rivista]
Bellesia, Franco; Forti, Luca; E., Gallini; Ghelfi, Franco; Libertini, Emanuela; Pagnoni, Ugo Maria
abstract

Monodispersed telechelic oligomers have been efficiently prepared by Fe-0-FeCl3 promoted halogen atom transfer radical of functional telogens and taxogens, (C) 1998 Elsevier Science Ltd. All rights reserved.

1997 - Ferrocene promoted addition of methyl 2,2-dichloro-carboxylates to 1-alkenes [Articolo su rivista]
Forti, Luca; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

The Kharasch addition of methyl 2,2-dichlorocarboxylates to 1-alkenes is promoted by ferrocene in DMF at 100 degrees C, affording 1:1 adducts in satisfactory yields.

1997 - Halogen atom transfer radical addition of alpha-polychloroesters to olefins promoted by Fe-0 filings [Articolo su rivista]
Forti, Luca; Ghelfi, Franco; Libertini, Emanuela; Pagnoni, Ugo Maria; Soragni, Ercole
abstract

The Kharasch addition of methyl 2,2-dichlorocarboxylates or trichloro acetic acid derivatives to alkenes, affording the corresponding 1:1 adducts, is promoted by the iron filings/N,N-dimethylformamide system.

1997 - Halogen atom transfer radical cyclization of N-allyl-N-benzyl-2,2-dihaloamides to 2-pyrrolidinones, promoted by Fe-0-FeCl3 or CuCl-TMEDA [Articolo su rivista]
M., Benedetti; Forti, Luca; Ghelfi, Franco; Pagnoni, Ugo Maria; R., Ronzoni
abstract

The halogen atom transfer radical cyclization of a N-allyl-N-benzyl-2,2-dihaloamides to 2-pyrrolidinones has been carried out in high yields under mild conditions, in a reaction promoted by CuCl-TMEDA or Fe-0-FeCl3 in acetonitrile or N,N-dimethylformamide, respectively.

1997 - The Fe-0 promoted addition of CCl4 and CCl3Br to olefins [Articolo su rivista]
Bellesia, Franco; Forti, Luca; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

The radical addition of CCl4 or CCl3Br to olefins is efficiently promoted by iron filings in N,N-dimethylformamide under mild conditions.

1997 - The reaction of the acetates of alpha-chloro methyl hemiacetals with nucleophiles. Synthesis of 2-hydroxy-1,4-dithianes [Articolo su rivista]
L., Antolini; Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

The acetates of the methyl hemiacetals of alpha-halo aldehydes, 1, easily undergo nucleophilic attack by lithium thiolates or ethane dithiolate affording alpha-thioalkyl aldehydes 2 or 2-hydroxy-1,4-dithianes 3, respectively. 3-monosubstituted dithianes 3 smoothly dehydrate to 2,3-dihydro-1,4-dithiines 4, whereas 3,3-disubstituted derivatives give dimers 6. The single-crystal X-ray analysis of 6b shows that it crystallises in a racemic form, with the dithiane ring in a chair conformation and the exocyclic S(3) atom axially bonded to the ring. The crystal packing appears to be determined mainly by a weak C-H ... O hydrogen bonding interaction.

1996 - Fe-0 initiated halogen atom transfer radical addition of methyl 2-Br-2-Cl-carboxylates to olefins [Articolo su rivista]
Forti, Luca; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

The halogen atom transfer radical addition (HATRA) of methyl 2-Br-2-Cl-carboxylates to alkenes is obtained in good yields by catalytic amounts of iron filings in dimethylformamide/1,2-dichloroethane at 80 degrees C under argon.

1996 - N-(2-hydroxyalkyl)-2,2-dihaloamides by amino-de-alkoxylation of methyl 2,2-dihalocarboxylates [Articolo su rivista]
Forti, Luca; Ghelfi, Franco; Grandi, Romano; Libertini, Emanuela; Pagnoni, Ugo Maria
abstract

The chemoselective N-acylation of 2-amino alcohols with methyl 2,2-dichloro carboxylates occurs smoothly and in excellent yields.

1996 - The CuBr/Fe-0 promoted radical addition of methyl 2-Br-2-Cl-carboxylates to olefins [Articolo su rivista]
Forti, Luca; Ghelfi, Franco; M., Lodi Lancellotti; Pagnoni, Ugo Maria
abstract

Methyl 2-Br-2-Cl-carboxylates afford 2-alkyl-2-Cl-4-Br-carboxylates in fair yields by reaction with terminal alkenes, under mild conditions, through a radical process promoted by CuBr/Fe-0 in DMF/CH2Cl2

1996 - Zinc promoted addition of methyl 2,2-dihalocarboxylates to carbonyl compounds [Articolo su rivista]
Benincasa, Marta; Forti, Luca; Ghelfi, Franco; Libertini, Emanuela; Pagnoni, Ugo Maria
abstract

Methyl 2,2-dihalocarboxylates add easily to carbonyl compounds in fair to good yields through the intermediate formation of 2-haloester enolates; the reaction is promoted by zinc, following a ''Barbier'' type procedure.

1995 - Amino-de-Alkoxylation of Methyl 2,2-Dihalocarboxylates [Articolo su rivista]
Forti, Luca; Ghelfi, Franco; F., Munari; Pagnoni, Ugo Maria
abstract

N-alkyl-2,2-dihaloamides were efficiently prepared by amino-de-alkoxylation of methyl 2,2-dihalocarboxylates, at room temperature without solvents and promoters. Excellent yields of anilides were obtained after addition of AlCl3.

1995 - Deprotection of α -halo aldehydes dimethyl acetals with acetic anhydride-acetyl chloride-sodium acetate trihydrate [Articolo su rivista]
M., Benincasa; M., Boni; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

Alpha-halo aldehydes are regenerated in excellent yields from the corresponding dimethyl acetals by acetic anhydride-acetyl chloride-sodium acetatetrihydrate in chloroform.

1995 - OXIDATION OF ALPHA-ACETOXY ACETALS WITH TRICHLOROISOCYANURIC ACID [Articolo su rivista]
Benincasa, M; Grandi, Romano; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

alpha-Acetoxy acid methyl esters are prepared in excellent yields by treating aliphatic alpha-acetoxy dimethyl acetals with trichloroisocyanuric acid in DMF.

1995 - REGIOSPECIFIC CONVERSION OF ALPHA,BETA-EPOXY ACETATES TO 3-CHLORO-2-HYDROXY ACETATES [Articolo su rivista]
Ghelfi, Franco; Grandi, Romano; Pagnoni, Ugo Maria
abstract

3-chloro-2-hydroxy acetates are easily obtained by treating alpha,beta-epoxy acetates with chlorotrimethylsilane-dimethyl sulphoxide in acetonitrile.

1995 - Reductive homo-coupling of methyl 2-Br-2-Cl-carboxylates promoted by CuBr-Fe0 [Articolo su rivista]
M., Benincasa; Forti, Luca; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

Dimethyl 2,3-dialkyl-2,3-dichloro-butanedioates are efficiently prepared in dimethylformamide or dimethylsulphoxide, through reductive homo-coupling of methyl 2-bromo-2-chlorocarboxylates promoted by CuBr-Fe-0.

1995 - Stereoselective Dehydrobromination of alkyl alpha-Br-alpha-Cl-carboxylates [Articolo su rivista]
Forti, Luca; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

(Z)-Alkyl alpha-Cl-alpha,beta-unsaturated esters are prepared in excellent yields by stereoselective dehydrobromination of alkyl alpha-Br-alpha-Cl-carboxylates with LiCl-Li2CO3 in dimethylformamide.

1995 - The CuBr/Fe promoted olefin alkylation of 2-Br-2-Cl-carboxylate methyl esters [Articolo su rivista]
Forti, Luca; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

Methyl 2-Br-2-Cl-carboxylates react with 1-octene in DMF/CH2Cl2 in a radical process promoted by CuBr/Fe, yielding 2-alkyl-2-Cl-4-Br-carboxylates smoothly and efficiently.

1995 - gamma-Alkylketene dithioacetals from 2,3-dichloroaldehyde dithioacetals [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

The preparation of 2,3-dichloroaldehyde dithioacetals and their conversion to ketene dithioacetals by base are reported.

1994 - An efficient procedure to alfa-hydroxyaldehyde dimethyl acetals [Articolo su rivista]
M., Boni; Forti, Luca; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

Alpha-Hydroxyaldehyde dimethyl acetals are prepared efficiently by conversion of alpha-haloaldehyde dimethyl acetals into alpha-haloaldehyde hemiacetal acetates and subsequent methanolysis promoted by lithium methoxide.

1994 - METHYL ALPHA,ALPHA-DICHLORO-ESTERS BY OXIDATION-CHLORINATION OF CYCLIC ACETALS WITH TRICHLOROISOCYANURIC ACID [Articolo su rivista]
Bellesia, Franco; Boni, M; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

Methyl alpha-chloro- or alpha,alpha-dichloro-esters are obtained in excellent yields by oxidation chlorination of 2-alkyl-4,5-dimethyl-1,3-dioxolanes with trichloroisocyanuric acid.

1994 - PREPARATION OF 2,2-DIHALOCARBOXYLIC ACID METHYL-ESTERS BY OXIDATION CHLORINATION OF 2-(1-HALOALKYL)-4-METHYL-1,3-DIOXOLANES WITH TRICHLOROISOCYANURIC ACID [Articolo su rivista]
Boni, M; Ghelfi, Franco; Pagnoni, Ugo Maria; Zucchi, C.
abstract

Methyl 2,2-dichloro or 2-bromo-2-chloro carboxylates were obtained in excellent yields by oxidation-chlorination of 2-(1-haloalkyl)-4-methyl-1,3-dioxolanes with trichloroisocyanuric acid.

1994 - REDUCTIVE COUPLING OF METHYL ALPHA-BROMO-ALPHA-CHLOROCARBOXYLATES [Articolo su rivista]
Boni, M; Ghelfi, Franco; Pagnoni, Ugo Maria; Zucchi, Claudia
abstract

CuBr-LiOCH3 in methanol efficiently promotes the reductive coupling of methyl alpha-bromo-alpha-chlorocarboxylates to dimethyl alpha,alpha'-dichloro-succinates.

1994 - REGIOSPECIFIC HYDROGEN-CHLORIDE ELIMINATION FROM ALPHA,BETA-DICHLOROALKYL PHENYL SULFIDES [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

alpha,beta-Dichloroalkyl phenyl sulphides undergo regiospecific hydrogen chloride eliminations to afford alpha- or beta-chloro-1-alkenyl phenyl sulphides in good yields.

1994 - SULFOXIDES FROM THIOETHERS AND MNO2-HCL [Articolo su rivista]
Fabretti, A; Ghelfi, Franco; Grandi, Romano; Pagnoni, Ugo Maria
abstract

Treatment of thioethers with manganese(IV)oxide-35% aqueous hydrogen chloride in methanol gives sulfoxides in high yields; sulfones are not produced

1994 - SYNTHESIS OF 2-(1-CHLOROALKYL)-1,3-BENZODITHIOLES AND 2-ALKYLIDENE-1,3-BENZODITHIOLES [Articolo su rivista]
Bellesia, Franco; M., Boni; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

Boron trifluoride promoted transdithioacetalization of alpha-chloroacetals with 1,2-benzodithiol affords good yields of 2-(1-chloroalkyl)1-3-benzodithioles, which dehydrochlorinates very satisfactorily to the corresponding 2-alkylidene-1,3-benzodithioles.

1994 - TRICHLOROISOCYANURIC ACID OXIDATION OF 2-CHLORO ALDEHYDE ACETALS TO 2-CHLORO ACID-ESTERS [Articolo su rivista]
Boni, M; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

2-Chloro acid methyl esters were prepared in good yields treating 2-chloro aldehyde dimethyl acetals with trichloroisocyanuric acid in DMF. Aldehyde dimethyl acetals with the 2-halogen on a tertiary carbon atom were poorly reactive and could be oxidized effeciently only after their transformation into 1,3-dioxolanes.

1993 - ALPHA-CHLOROMERCAPTALS FROM ALPHA-CHLOROACETALS AND THIOLS [Articolo su rivista]
Bellesia, Franco; Boni, M; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

Alpha-chloromercaptals are prepared in good yields by a CoCl2-trimethylchlorosilane catalysed transdithioacetalization of alpha-chloroacetals with thiols in acetonitrile.

1993 - CARBONYL REGENERATION FROM OXIMES AND SEMICARBAZONES BY TRIMETHYLCHLOROSILANE-DIMETHYLSULFOXIDE [Articolo su rivista]
Ghelfi, Franco; Grandi, Romano; Pagnoni, Ugo Maria
abstract

Treatment of oximes and semicarbazones of saturated and (alpha,beta-unsaturated ketones and aldehydes with trimethylchlorosilane-dimethyl sulphoxide in dry acetonitrile affords the corresponding carbonyl compounds in excellent yields under mild conditions.

1993 - DIMETHYLACETALS BROMINATION BY Br2-TRIMETHYLCHLOROSILANE-NaBr [Articolo su rivista]
Bellesia, Franco; Boni, M; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

α-Bromo di-Me acetals are obtained in excellent yields by treating di-Me acetals with Br2-NaBr-chlorotrimethylsilane in CH3OH/CH3CN (2:1). The method is suitable for large scale prepn.

1993 - KETENE THIOACETALS FROM ALPHA-CHLOROMERCAPTALS [Articolo su rivista]
Bellesia, Franco; Boni, M; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

Excellent yields of ketene thioacetals are obtained from 2-(1-chloroalkyl)-1,3-dithiolanes or 2-(1-chloroalkyl)-1,3-dithianes.

1993 - OXIDATION OF THIOETHERS BY MANGANESE(IV) OXIDE-TRIMETHYLCHLOROSILANE [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

Thioethers are transformed by manganese(IV) oxide-trimethylchlorosilane in CH3OH in high yields to sulphoxides, exclusively.

1993 - REGENERATION OF ALPHA-HALOALDEHYDES FROM ALPHA-HALODIMETHYLACETALS [Articolo su rivista]
Boni, M; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

Alpha-Chlorodimethylacetals are hydrolysed in a mixture of acetic acid and aq. HCI (3.5 M) to alpha-chloroaldehydes in excellent yields. On replacing HCI by HBr the same procedure is applied to alpha-bromodimethylacetals.

1993 - THE REACTION OF ALKYL PHENYL SULFIDES WITH MANGANESE-DIOXIDE AND ACETYL-CHLORIDE [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

In a one-pot reaction, manganese dioxide in stoicheiometric amounts and acetyl chloride transform alkyl phenyl sulphides into the corresponding 1-alkenyl phenyl sulphides; these latter products can undergo chlorination of the double bond promoted by the excess manganese dioxide.

1993 - THE REACTION OF PYRROLES WITH TRIMETHYLHALOSILANES-DIALKYL SULFOXIDES [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Grandi, Romano; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

Pyrroles are powerful nucleophiles in the reaction with dialkyl sulfoxides and trimethylchlorosilane (TMCS) or trimethylbromosilane (TMBS), affording sulfonium salts or halo derivatives, generally in good yields.

1992 - ACETAL CHLORINATION WITH MNO2-TRIMETHYLCHLOROSILANE [Articolo su rivista]
Bellesia, Franco; Boni, M; Ghelfi, Franco; Grandi, Romano; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

alpha-Chloroacetals am obtained in almost quantitative yields, by treating acetals with MnO2-trimethylchlorosilane in CH3OH:CH3CN (1:1). The halogenation is explained by a ligand-transfer process on an enolether intermediate, mediated by a Mn(IV)-chloride species.

1992 - BETA-CHLOROALKYL SULFIDES FROM ME2S/SO2CL2/ME2SO AND ALKENES [Articolo su rivista]
Bellesia, Franco; Boni, M; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

A novel method to prepare beta-chloroalkyl sulfides from alkenes and Me2S-SO2Cl2-Me2SO is described, methanesulfenyl chloride being suggested as intermediate.

1992 - CARBONYL REGENERATION FROM PARA-TOLUENSULFONHYLHYDRAZONES BY TRIMETHYLCHLOROSILANE-DIMETHYLSULFOXIDE [Articolo su rivista]
Ghelfi, Franco; Grandi, Romano; Pagnoni, Ugo Maria
abstract

Treatment of p-tosylhydrazones of saturated and alpha,beta-unsaturated ketones and aldehydes with trimethylchlorosilane-dimethyl sulphoxide in dry acetonitrile affords the corresponding carbonyl compounds in excellent yields under mild conditions.

1992 - THE REACTION OF BENZYLIC ALCOHOLS WITH CHLOROTRIMETHYLSILANE/DIMETHYL SULFOXIDE [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

With catalytic amounts of chlorotrimethylsilane/dimethyl sulphoxide (CTMSO/DMSO) in acetonitrile benzylic alcohols have been found to give high yields of styrenes. By using stoicheiometric amounts of reagents, different reaction pathways are observed: an elimination-addition sequence occurs with secondary and tertiary alcohols affording vicinal dichloro derivatives, beta-chloro thioethers and allyl chlorides, whereas a nucleophilic substitution to the corresponding monochlorides occurs star-ting from primary and sterically hindered substrates.

1991 - Chlorination of alkenes with manganese dioxide-manganese dichloride-acetyl chloride in dimethylformamide [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

Manganese(IV)ossido, MnCl2, acetil cloruro, N,N-dimetilformamide,alcheni, clorurazione

1991 - ON THE INTERMEDIATES OF THE REACTION OF KETONES WITH MNO2-CHLOROTRIMETHYLSILANE [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

The chlorination of ketones with MnO2-chlorotrimethylsilane occurs through an enolization catalyzed by an Mn(IV) species, which is also involved in the halogenation of alkenes.

1991 - REACTION OF MANGANESE(III) ACETATE-ACETYL CHLORIDE WITH BENZENES [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

Manganese(III) acetate-acetyl chloride smoothly halogenates benzenes at the aromatic nucleus while benzylic chlorination is observed on substrates bearing an electron-donor substituent and an ortho or para methyl group; the results are rationalized by a reaction pathway involving a single electron transfer from the substrate to a manganese(III) species.

1991 - THE REACTION OF STYRENES WITH CHLOROTRIMETHYLSILANE DIMETHYL-SULFOXIDE [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

The chlorotrimethylsilane-dimethyl sulphoxide reagent system gives rise to smooth and high yield transformations of: i) beta-alkyl- and beta,beta-dialkyl-styrenes into vicinal dichlorides, ii) alpha,beta-dialkyl- and alpha,beta,beta-trialkyl-styrenes into allyl chlorides.

1990 - PHOTO-OXIDATION OF METHYL LINOLEATE AND THE EFFECT OF ALFA-TOCOPHEROL, ASORBIC ACID BETA-CAROTENE AND HEAVY METAL IONS [Capitolo/Saggio]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

The effect of antioxidant vitamins A, C and E on the photo-oxidation of methyl linoleate was studied.

1990 - The chlorination of ketones with manganese(IV) chloride [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

In situ formation of MnCl4 by reaction of MnO2 with ClSiMe3 or AcCl followed by reaction with a ketone gives the α-chloro ketone. A CH2 group is attacked in preference to a Me group; steric factors limit the chlorination of CH groups.

1989 - Chlorination of Alkenes with Manganese Dioxide-Trimethylchlorosilane [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; A., Pinetti
abstract

The title reagent system (MnO2-TMCS) give rise to a smooth and high-yeld chlorinationof unconiugated alkenes without isomerization occurring. The trans vic-dichloro derivatives are obtained from cyclic substrates with high stereoselectivity.

1989 - DIENE CHLORINATION WITH MANGANESE-DIOXIDE TRIMETHYL-CHLOROSILANE [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

Reaction of dienes, e.g. H2C:CH(CH2)nCH:CH2 (n = 2-4), Me2C:CHCH2CH2CMe:CHCH2OAc, 1,5- and 1,4-cyclooctadiene, and 4-vinylcyclohexenes, with the title reagents resulted in chlorination of the more highly substituted double bond.

1989 - The treatment of indoles with trimethylhalogenosilanes and sulphoxides J. Chem. Res. (S) 1989, 182 [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

Indole derivs. I (R = H, Me; R1 = H, Me, Ph; R2 = H) were treated with DMSO and Me3SiCl to give I (same R, R1; R2 = S+Me2 Cl-). Treatment of I with Me3SiCl and Et2S(O) gave mainly I (same R, R1; R2 = Cl). No sulfonium compds. were formed when I (R = R2 = H; R1 = H, Me) were treated with Me3SiCl and Bu2S(O) or with Me3SiBr and DMSO. Treatment of I (R = H, R1 = R2 = Me) with Me3SiCl and DMSO gave 56% I (R = H, R1 = Me, R2 = CHO). The formation of different electrophilic S or Cl species is given as an explanation for product formation.

1988 - Facile conversion of α,β-epoxy ketones to 2-chloro-3-hydroxy ketones by trimethylchlorosilane-dimethyl sulfoxide [Articolo su rivista]
Ghelfi, Franco; G., Romano; Pagnoni, Ugo Maria
abstract

Title cleavage of epoxy ketones proceeded stereo- and regiospecifically to give 2-chloro-3-hydroxy ketones. Aryl epoxides afforded the isomeric 2-hydroxy-3-chloro ketones. Thus, treatment of epoxide I with Me3SiCl-Me2SO in MeCN at room temp. afforded 96% chlorohydrin HOCMe2CHClCOMe.

1987 - THE REACTION OF THRICHLORO AND TRIMETHYLBROMOSILANE-DIMETHYLSULFOXIDE REAGENT SYSTEM ON ALKENES [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; Pinetti, Adriano
abstract

Me3SiCl-DMSO combine to form a reagent which transforms alkenes (e.g., BuCMe:CH2, 1-methylcyclohepxene, norbornene) into 2-chloroalkyl Me sulfides [e.g., BuCMeClCH2SMe, 1-chloro-1-methyl-2-(methylthio)cyclohexane, chloro(methylthio)norbornane I] regio- and stereoselectively.

1987 - TRIMETHYLCHLOROSILANE-MEDIATED FORMATION OF 2-CHLOROCYCLOHEXYL SULPHIDES BY SULPHOXIDES [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria
abstract

The title 2-chlorocyclohexyl sulfides, e.g. I (R = Me, Et, Me2CH, Bu) were prepd. by treating cyclohexene with the corresponding alkyl sulfoxides RSOR in the presence of Me3SiCl. Unsym. sulfoxides, e.g. EtSOBu gave a mixt. of products I (R = Et, Bu). Tetramethylene sulfoxide (II) gave aldehyde I (R = CH2CH2CH2CHO) as the major product. A mechanism is presented in which 2 mol. of sulfoxide form an intermediates S-alkoxysulfonium salt.

1986 - REACTIONS OF THE TRIMETHYLCHLOROSILANE-DIMETHYL SULPHOXIDE REAGENT WITH CARBONYL COMPOUNDS [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Grandi, Romano; Pagnoni, Ugo Maria
abstract

The Me3SiCl-Me2SO system is an efficient reagent for the smooth chlorination of unconjugated carbonyl compds. at the more substituted α-carbon atom. β-Dicarbonyl substrates are transformed into α-chloro-α-thiomethyl ether derivs.

1986 - Regioselective alfa-Bromination of Carbonyl Compounds with Trimethylbromosilane-Dimethyl Sulphoxide [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; R., Grandi; Pagnoni, Ugo Maria
abstract

Trimethylbromosilane-Dimethyl Sulphoxide (TMBS-DMSO) reagent system brominates efficiently and regiospecifically at the more alkyl-substituted alfa-position of carbonyl compounds

1986 - The Base-Catalyzed Cyclization of 10-Oxocitral Synthesis of Chrysomelidial and Dehydroiridodial [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Pagnoni, Ugo Maria; A., Pinetti
abstract

Base treatment of 10-oxocitral gives chrysomelidial and dehydroiridodial, supporting its intermediacy in the biosynthesis of some iridoid glucosides.

1985 - Base-promoted rearrangement of 2,3-epoxycyclohexanones to phenols [Articolo su rivista]
Bellesia, Franco; Ghelfi, Franco; Grandi, Romano; Pagnoni, Ugo Maria
abstract

The reactions were examd. of ten 2,3-epoxycyclohexanones with NaH in (MeOCH2)2; the products were trapped by treatment with Me3CSiMe2Cl and Et3N. Generally, the main reaction products were the corresponding silylated phenols. E.g., carvone epoxide gave 66% 3,4-Me3CSiMe2O(Me)C6H3CMe:CH2. This aromatization proceeds by deprotonation at the α'-C atom followed by O-silylation, β'-proton removal, olefinic bond shift, oxirane ring cleavage, and 1,2-elimination.

1984 - Biosynthesis of Nepetalactone in Nepeta Cataria [Articolo su rivista]
Bellesia, Franco; R., Grandi; Pagnoni, Ugo Maria; A., Pinetti; R., Trave
abstract

Iridodial is a key intermediate in the biosynthesis of nepetalactone. One of the speps on the pathway prior the lactonization is a hydride shift from C-1 to C-10. 10-Hydroxycitronellol is a far more efficient precursor than the C-2/C-3 unsaturated analogue.

1984 - The Intermediacy of Iridodial in the Biosynthesis of Dolicholactone in Teucrium Marum [Articolo su rivista]
Bellesia, Franco; Pagnoni, Ugo Maria; A., Pinetti; R., Trave
abstract

Feedings experiments using 3H-labelled cyclopentane monoterpenes show that in dolicholactone two hydride sfifts give rise to lactone ring and olefinic bond formation.

1983 - Teucrein, a New Iridolactol from Tecrium marum and its Biosynthetic Relationship with Dolchodial [Articolo su rivista]
Bellesia, Franco; Pagnoni, Ugo Maria; A., Pinetti; R., Trave
abstract

The title compound, the diacetate of 9-hydroxy-derivative of the enol-lactol tautomer of iridodial, has been isolated from Teucrium marum in its role in the biosynthesis of cyclopentanoids is discussed.

1983 - The Biosynthesis of Dolichodial in Teucrium marum [Articolo su rivista]
Bellesia, Franco; Pagnoni, Ugo Maria; A., Pinetti; R., Trave
abstract

The biosynthesis of Dolichodial in Teucrium marum appers to proceed through 10-hydroxycitronellol as the key intermediate and retains the non equivalency of C-9 and C-10. The relatively low incorporation of iridodia indicates that the olefinic bond is most likely formed by an oxidative process before ring-closure.

1983 - The action of Sulphuryl Chloride on p-Tosylhydrazones [Articolo su rivista]
Bellesia, Franco; R., Grandi; Pagnoni, Ugo Maria; A., Pinetti
abstract

The reaction of sulphuryl chloride with different substituted p-Tosylhydrazones is found to afford various geminal dichloro-hydrocarbons, the parent carbonyl compounds, or alfa-alfa-dichloroaldehydes; a reaction mechanism involving two competing pathways is proposed.

1982 - N-N Bond Cleavage of 1-Acyl-2p-tosylhydrazines with Sulphur Mono- and Di-chloride. [Articolo su rivista]
Bellesia, Franco; Pagnoni, Ugo Maria; A., Pinetti
abstract

The distribution of main products of the reaction of 1-Acyl-2p-tosylhydrazines with S2Cl2, SCl2, SOCl2 and SO2Cl2 is summarized.

1981 - A Route to 3,4-Polymethylenepyrazoles via Olefinic Toluene-p-sulphonylhydrazones [Articolo su rivista]
Bellesia, Franco; R., Grandi; Pagnoni, Ugo Maria
abstract

Tosylhydrazones of cycloalkenyl carbonyl compounds were subjected to base-catalysed decomposition (K2CO3-MeOH) in aim to obtain 3,4-polymethylenepyrazoles. The cycloaddition occours in high yelds and solvolysis competes with cycloaddition only with cyclopentenyl derivative.

1981 - Attempted Nucleophilic Attack of Cyanide Ion on alfa-beta-unsaturated p-Tosylhydrazones. [Articolo su rivista]
Bellesia, Franco; Pagnoni, Ugo Maria; A., Pinetti
abstract

The reactivity of alfa-beta-unsaturated p-Tosylhydrazones toward ion cyanide as nucleophile. In a aqueous-dichloromethane two-phases reaction, using benzyltriethyammonium chloride as a phase-transfer catalyst, we obtained hydrocyanation of tosylhydrazones of cycloexanone and other unconjugated substrates, while the C=N of conjugated one, resists nucleophilic attack of cyanide ion.

1981 - Base and Acid Decomposition of Unsatarated 1-Acyl-2-Tosylhydrazines. [Articolo su rivista]
Bellesia, Franco; R., Grandi; Pagnoni, Ugo Maria; R., Trave
abstract

In treating olefinic acyl-p-tosylhydrazides with reducing, acidic or basic agents, the reactivity of carbon-nitrogen double bond towards hydride ion is drastically reduced in conjugated acyl substrates. Under severe reaction condition tars and many by-products are formed. In alkaline condition alfa-beta unsaturated substrates were almost unchanged and ring closure was never observed.

1981 - The Photolysis of p-Tosylhydrazones of Aryl and alfa,beta-Unsaturated Carbonyl Compounds [Articolo su rivista]
Bellesia, Franco; R., Grandi; Pagnoni, Ugo Maria; R., Trave
abstract

Azines and sulphones are the major transformation products of p-tosylhydrazones of conjugated (olefinic and aromatic) carbonyl compounds under u.v. irradiation

1981 - The Reaction of alfa,beta-Unsaturated p-Tosylhydrazones with Sulphur Chlorides [Articolo su rivista]
Bellesia, Franco; R., Grandi; Pagnoni, Ugo Maria; R., Trave
abstract

alfa,beta-unsaturated p-tosylhydrazones react with tetravalent and divalent sulphur chlorides affording 1,2,3-thiadiazoles in good yields.

1979 - Some Anomalous Products from the Attempted Halogenation of Unsaturated Alcohols by the Complex from Dimethyl Sulphide and N-Halogenosuccinimide [Articolo su rivista]
Bellesia, Franco; R., Grandi; Pagnoni, Ugo Maria; R., Trave
abstract

Intramolecular participation of carbon-carbon double bonds and hydroxy-groups can occur when alcohols are treted with complexes derived from dimethyl sulphide and N-halogenosuccinimide. Neighbouring group participation is more common in the reactions in which N-bromosuccinimide rather than N-chlorosuccinimide is employed, the results suggest caution when the alcohol to halide conversion is attempted in certain polyfunctional molecules.

1979 - Synthesis and Molecular Structures of (1S)-cis,cis-Iridolactones [Articolo su rivista]
Bellesia, Franco; Pagnoni, Ugo Maria; R., Trave; G. D., Andreetti; G., Bocelli; P., Sgarabotto
abstract

Two cis,cis-iridolactones with a natural (S)-configuration at C(1) have been synthetized and their crystal and molecular structures determined by direct methods and refined by least-squares to R 0.109 and 0.064. The heterocyclic ring has a boat conformation which allows the C (8) methyl group to assume an equatorial position.Spectroscopic measurements indicate that this type of geometry is also present in solution.

1978 - Conformational Aspects of Agerol, A Ten-Membered-Ring Sesquiterpene [Articolo su rivista]
Bellesia, Franco; Pagnoni, Ugo Maria; A., Pinetti; R., Trave
abstract

The conformation of agerol, a ten-membered-ring sesquiterpene fron Achillea ageratum, has been investigated by means of NMR and molecular mechanics calculations (GEMO program). The more stable formis very similar to that previously determined foe the corresponding diepoxide and accounts for the reactivity of the molecule. The minimization strain-energy procedure has been extended to compounds obtained by rearrangement of the cyclodecane skeleton of agerol.

1976 - Stereospecific Cyclisation of Agerol to an Isovetivane Carbon Framework [Articolo su rivista]
Bellesia, Franco; Pagnoni, Ugo Maria; R., Trave
abstract

Acid-catalysed conversion of a germacrane sesquiterpene into compounds with the unknown isovetivane framework was carried out by using aqueous acetic acid

1976 - The Configuration of the C(5) Carbon Atom in the Germacranic Sesquiterpene Ageratriol [Articolo su rivista]
Bellesia, Franco; Pagnoni, Ugo Maria; R., Trave
abstract

The configuration R for the C(5) atom in ageratriol has already been proposed on the basis of the results of asymmetrical esterification. It is now confirmed by transformation into a meso compound.

1975 - Biosynthesis of the Sesquiterpenoid Ageratriol [Articolo su rivista]
Bellesia, Franco; R., Grandi; A., Marchesini; Pagnoni, Ugo Maria; R., Trave
abstract

Ageratriol is biosynthesized from agerol through a diepoxide derivative. Mevalonic acid incorporation revealed that the formation of the isoprenylic double bond is not stereospecific.

1974 - Biogenetic-type Conversion of Agerol into Ageratriol [Articolo su rivista]
Bellesia, Franco; Pagnoni, Ugo Maria; R., Trave
abstract

The route of the "ene" reaction for the in vitro conversion of agerol into ageratriol is considered. The absolute configuration is then given.

1973 - On some Derivatives of 2-Hydroxyglutaric Acid [Articolo su rivista]
Bellesia, Franco; L., Garanti; Pagnoni, Ugo Maria
abstract

S- and R-acetoxyglutaric acid dimethyl esters are synthesized starting from S and R glutamic acids. Specific optical rotation values given in the literature for some derivatives of 5-oxo-2-S-tetrahydrofuronic acid, an intermediate in the above synthesis, are corrected.