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Your search keyword '"Mincione, Enrico"' showing total 186 results
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186 results on '"Mincione, Enrico"'

5. A new and efficient synthesis of unnatural amino acids and peptides by selective 3,3-dimethyldioxirane side-chain oxidation

Author

Saladino, Raffaele, Mezzetti, Maurizio, Mincione, Enrico, Torrini, Ines, Paradisi, Mario Paglialunga, and Mastropietro, Gaia

Subjects
Chemistry, Organic -- Research, Amino acids -- Research, Peptides -- Research, Biological sciences, Chemistry
Abstract

Research has been conducted on the synthesis of unnatural amino acids and peptides. Experiments demonstrate regioselectivity in the 3,3-dimethyldioxirane side-chain oxidation of dipeptides and tripeptides.

Published
1999

6. Manganese tetraphenylporphyrin-catalyzed stereoselective epoxidation of thymidine nucleosides

Author

Tagliatesta, Pietro, Bernini, Roberta, Crestini, Claudia, Monti, Donato, Boschi, Tristano, Mincione, Enrico, and Saladino, Raffaele

Subjects
Epoxy compounds -- Research, Porphyrins -- Research, Thymidine -- Research, Nucleosides -- Research, Biological sciences, Chemistry
Abstract

Research was conducted to examine an efficient and stereoselective manganese tetraphenylporphyrin-catalyzed epoxidation of thymidine nucleosides. An analysis of a possible role of the molecular recognition processes between manganese porphyrins and OH groups in the 2'-deoxyribose moiety on the stereochemistry of the oxidation was also carried out. Results suggest a relationship between the diastereoisomeric ratio of the final epoxides and the hydrogen-bonding interaction between the OH groups of the sugar moieties and the OCH3 groups of the catalysts during the approach of the nucleosides to the macrocycle core.

Published
1999

7. Mechanism of degradation of purine nucleosides by formamide. Implications for chemical DNA sequencing procedures

Author

Saladino, Raffaele, Mincione, Enrico, Crestini, Claudia, Negri, Rodolfo, Di Mauro, Ernesto, and Costanzo, Giovanna

Subjects
Purines -- Research, Nucleosides -- Research, DNA sequencers -- Methods, Chemistry
Abstract

The reaction of formamide with 2'-deoxyadenosine and 2'-deoxyguanosine results in imidazole ring opening by nucleophilic addition on the electrophilic C(8)-position of the purine ring. The degradation pattern of purine nucleosides allows the improvement of the DNA chemical sequencing procedure based on the base-selective reaction of formamide with DNA. The reactions of several 7-deazapurine analogues with formamide are also presented.

Published
1996

9. Regio- and stereoselective epoxidation of steroidal 1,4-diene 3-ones by dimethyldioxirane: a new access to A-norsteroids and to a class of estrogen synthetase inhibitors

Author

Bovicelli, Paolo, Lupattelli, Paolo, and Mincione, Enrico

Subjects
Steroids (Drugs) -- Analysis, Oxidation-reduction reaction -- Analysis, Stereochemistry -- Analysis, Biological sciences, Chemistry
Abstract

Epoxidation reactions of 1,4-diene 3-one systems with dimethyldioxirane reveal greater regioselectivities toward the less nucleophilic double bond. A carboxyl group at C11 induces high regioselectivity in the epoxidation of 1,4-androstadiene-3,11,17-trione to (1)alpha,(2)alpha-oxirane. The C11 carbonyl moiety exhibits a stereoorienting effect to favor the alpha-face approach of dimethyldioxirane. This epoxidation technique facilitates the synthesis of key intermediates for the synthesis of A-norsteroids.

Published
1994

13. Direct hydroxylation at the side-chain C-25 of cholestane derivative and of vitamin D3 Windaus-Grundmann ketone

Author

Bovicelli, Paolo, Lupattelli, Paolo, Mincione, Enrico, Prencipe, Teresa, and Curci, Ruggero

Subjects
Cholesterol -- Research, Vitamin D3 -- Research, Ethylene oxide -- Usage, Hydroxylation -- Methods, Oxidation-reduction reaction -- Methods, Biological sciences, Chemistry
Abstract

Dimethyldioxirane (DMDO) or its trifluoromethyl analogue (TFMD) allows the direct and highly regioselective oxyfunctionalization of cholestanes and of the vitamin D3 derivative Windaus-Grundmann ketone. The hydroxylations of 5-alpha,6-beta-dibromo-3-beta-acetoxycholestane, the vitamin D3 derivative and 3-beta-acetoxy-5-alpha-cholestane are carried out at 20 degrees C in a DMDO/acetone solution or at -40 to 0 degree C in a trifluoropropanone/acetone solution of TFMD. TFMD offers higher conversion rates (78-87%) and shorter reaction times. The selectivity is due to the sensitivity of dioxirane O-insertions to steric factors.

Published
1992

14. Oxidation of natural targets by dioxiranes: oxifunctionalization of steroids

Author

Bovicelli, Paolo, Lupatteli, Paolo, and Mincione, Enrico

Subjects
Ethylene oxide -- Usage, Oxo compounds -- Usage, Oxidation-reduction reaction -- Methods, Steroids (Drugs) -- Research, Biological sciences, Chemistry
Abstract

Dioxiranes find an important use as reagents in the oxidation of such natural compounds as steroids. A study of five steroids (cholesten-3-one, progesterone, 3-beta-hydroxy-5,16-pregnadien-20-one acetate, prednisone acetate and estrone acetate) is undertaken to determine the mechanism of their epoxidation with dioxirane. Dimethyldioxirane is stirred into an acetone solution of the steroid substrate. The limiting transition state is found to be spiro in structure. Kinetic and other aspects of the reactions are also discussed.

Published
1992

15. New and efficient syntheses of hydroxytyrosol and its lipophilic derivatives

Author

Barontini, Maurizio, Crisante, Fernanda, Fabrizi, Giancarlo, and Mincione, Enrico

Subjects
Lipophilic hydroxytyrosol derivatives, 2-Iodoxybenzoic acid (IBX), Hydroxytyrosol, Aromatic hydroxylation
Abstract

New and efficient oxidative procedures to synthesize hydroxytyrosol and its lipophilic derivatives are described. Starting materials are available and natural compounds such as tyrosol and homovanillyl alcohol. The oxidants of choice are both homogeneous and heterogeneous 2-iodoxybenzoic acid (IBX and IBX-polystyrene) able to perform the aromatic hydroxylation and the oxidative demethylation of phenolic compounds with a chemo and regioselectivity similar to that of the polyphenol oxidase and cytochrome P450. The reactions proceed quickly and the final products are isolated in good yields and high purity. After the first oxidation, IBX-polystyrene is recovered by simple filtration, regenerated and reused for more cycles of oxidation reactions without loss of efficiency

Published
2010

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