Enantiomerically pure (5R)-(-)-5-phenyl-4,5-dihydroisoxazole-3-carboxylic acid ethyl ester was obtained via enzymatic resolution of the corresponding racemic mixture using a lipase from hog pancreas (PPL). The following reduction of the ester group to the corresponding alcohol and the oxidation of the latter led to (5R)-(-)-5-phenyl-4,5-dihydroisoxazole-3-carbaldehyde, and the reaction between this and Schöllkopf's reagent, (2R)-(+)-2,5-dihydro-3,6-dimethoxy-2-isopropylpyrazine, gave mixtures of adducts with a good syn/anti ratio. The steric configurations of the major diastereoisomer were assigned on the basis of spectroscopic data and X-ray analysis. The subsequent controlled hydrolysis of the pyrazine ring led to β-(5-phenyl-4,5-dihydroisoxazol-3-yl)-serine methyl esters and the corresponding dipeptides with (R)-valine. Finally, reductive cleavage of the 4,5-dihydroisoxazole ring under hydrolytic conditions made it possible to obtain the corresponding polyfunctionalised dipeptides.

Enzymatic resolution of (±)-5-phenyl-4,5-dihydroisoxazole-3-carboxylic acid ethyl ester and its transformations into polyfunctionalised amino acids and dipeptides / G. Cremonesi, P. Dalla Croce, A. Forni, M. Gallanti, R. Gandolfi, C. La Rosa. - In: TETRAHEDRON-ASYMMETRY. - ISSN 0957-4166. - 20:16(2009), pp. 1940-1947. [10.1016/j.tetasy.2009.07.025]

Enzymatic resolution of (±)-5-phenyl-4,5-dihydroisoxazole-3-carboxylic acid ethyl ester and its transformations into polyfunctionalised amino acids and dipeptides

G. Cremonesi
Primo
;
P. Dalla Croce
Secondo
;
M. Gallanti;R. Gandolfi
Penultimo
;
C. La Rosa
Ultimo
2009

Abstract

Enantiomerically pure (5R)-(-)-5-phenyl-4,5-dihydroisoxazole-3-carboxylic acid ethyl ester was obtained via enzymatic resolution of the corresponding racemic mixture using a lipase from hog pancreas (PPL). The following reduction of the ester group to the corresponding alcohol and the oxidation of the latter led to (5R)-(-)-5-phenyl-4,5-dihydroisoxazole-3-carbaldehyde, and the reaction between this and Schöllkopf's reagent, (2R)-(+)-2,5-dihydro-3,6-dimethoxy-2-isopropylpyrazine, gave mixtures of adducts with a good syn/anti ratio. The steric configurations of the major diastereoisomer were assigned on the basis of spectroscopic data and X-ray analysis. The subsequent controlled hydrolysis of the pyrazine ring led to β-(5-phenyl-4,5-dihydroisoxazol-3-yl)-serine methyl esters and the corresponding dipeptides with (R)-valine. Finally, reductive cleavage of the 4,5-dihydroisoxazole ring under hydrolytic conditions made it possible to obtain the corresponding polyfunctionalised dipeptides.
Settore CHIM/11 - Chimica e Biotecnologia delle Fermentazioni
Settore CHIM/06 - Chimica Organica
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/71738
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