Fulvia Orsini

1,3 Dipolar cycloadditions of azomethine ylides with aromatic aldehydes. syntheses of 1-oxapyrrolizidines and 1,3-oxazolidines.

Abstract Substituted 1-oxapyrrolizidines have been synthetized by cycloaddition of azomethine ylides, generated by aldehydes induced decarboxylation of proline, with carbonyl dipolarophyles. The stereochemistry of the cycloadducts indicate that they arise from the stereospecific formation of one isomer of the azomethine ylide.

Synthesis and Antinociceptive Activity of Chimonanthines and Pyrrolidinoindoline-Type Alkaloids

Hodgkinsine, a trimeric pyrrolidinoindoline type alkaloid, present as a major constituent of Psychotria spp. (Rubiaceae), has shown to produce dose-dependent, naloxone reversible, analgesic effect in thermal models of nociception and in the capsaicin-induced pain. SAR studies have been initiated by synthesizing the three diastereomeric dimers (chimonanthines) (11-13) which were evaluated in vitro and in vivo along with the synthetic intermediates. Strong binding affinities for mu opioid receptors were found for (-)- and (+)-chimonanthine monourethanes (9 and 10), whereas (-)-, (+)- and (meso)-chimonanthine (11-13) and hodgkinsine displayed low affinity. In vivo data have shown that only (+)-chimonanthine (12) and calycosidine resemble the analgesic profile found for hodgkinsine.

Reformatsky intermediate. A C-metallated species.

Abstract 13 C-NMR and 1 H-NMR spectra of the Reformatsky reagent from t-butylbr o moacetate, evidence a C-metallated species: within the limits of detectability of the methods, no O-metallated species can be detected in solution.

Biotransformation of styrenes by a Pseudomonas putida

SummaryA strain of Pseudomonas putida was isolated from soil in the presence of α-methylstyrene, as the sole carbon and energy source. The analysis of the oxidation products from culture broth allowed the identification of 2-phenyl-2-propen-1-ol and 1,2-dihydroxy-3-isopropenyl-3-cyclohexene suggesting the existence of different initial steps in the metabolism of α-methylstyrene. The same strain also oxidized styrene and produced by initial oxidation of the aromatic nucleus a compound identified as 1,2-dihydroxy-3-ethenyl-3-cyclohexene.

Alkaloid and lignan constituents of Cinnamosma madagascariensis

Abstract A new lignan glycoside, 5-methoxy-9-β-xylopyranosyl-(-)- isolariciresinol and two indole alkaloids have been characterised from the bark of Cinnamosma madagascariensis .

Synthesis and biological evaluation of 1,4-diaryl-2-azetidinones as specific anticancer agents: activation of adenosine monophosphate-activated protein kinase and induction of apoptosis

A series of novel 1,4-diaryl-2-azetidinones were synthesized and evaluated for antiproliferative activity, cell cycle effects, and apoptosis induction. Strong cytotoxicity was observed with the best compounds (±)-trans-20, (±)-trans-21, and enantiomers (+)-trans-20 and (+)-trans-21, which exhibited IC(50) values of 3-13 nM against duodenal adenocarcinoma cells. They induced inhibition of tubulin polymerization and subsequent G2/M arrest. This effect was accompanied by activation of AMP-activated protein kinase (AMPK), activation of caspase-3, and induction of apoptosis. Additionally, the most potent compounds displayed antiproliferative activity against different colon cancer cell lines, opening the route to a new class of potential therapeutic agents against colon cancer.

Bioconversion of substituted styrenes to the corresponding enantiomerically pure epoxides by a recombinant Escherichia coli strain

Abstract Enantiomerically pure epoxides are produced by bioconversion of the corresponding styrenes using a recombinant Escherichia coli strain containing the styrene monooxygenase gene cloned from Pseudomonas fluorescens ST. Different procedures were used to optimise yields and to permit product isolation. Conversion rates depend on the position and nature of the styrene substituent.

Saponins from Albizzia anthelmintica

Abstract The structures of three new saponins from the bark of Albizzia anthelmintica were established to be 3-O-[β- d -glucopyranosyl(1 → 3)] [α- l -arabinopyranosyl(1 → 2)] [α- l -arabinopyranosyl(1 → 6)] 2-acetamido-2-deoxy-β- d -glucopyranosyl echinocystic acid; 3-O-[α- l -arabinopyranosyl(1 → 2)][α- l -arabinopyranosyl(1 → 6)] 2-acetamido-2-deoxy-β- d -glucopyranosyl echinocystic acid and, present in small amounts, 3-O-[α- l -arabinopyranosyl(1 → 6)] 2-acetamido-2-deoxy-β- d -glucopyranosyl echinocystic acid.

C-Metallated reformatsky intermediates. Structure and reactivity.

Abstract 13C-NMR analysis of the Reformatsky intermediates from t-b u tyl-α-bromo acetate, t-b u tyl-α-bromo isobutyrate and t-b u tyl-α-bromo pr o pionate have evidenced C-metallated species. Their ability to act as n u cleophilic reagents under mild conditions and their selectivity towards h a logen-and oxygen containing electrophiles is reported.

Structure and absolute stereochemistry of vanillosmin, a guaianolide from Vanillosmopsis erythropappa

Abstract The structure and absolute stereochemistry of vanillosmin were established by chemical and spectral evidence and by comparison with O -acetyl-isophoto-α-santonic lactone and tetrahydroartabsin “C”.