Showing papers by "Pierre L. Beaulieu published in 1991"

Synthesis of chiral vinylglycines

Abstract: (R)- or (S)-benzyl 4-formyl-2,2-dimethyl-3-oxazolidinecarboxylate (7a) and (R)- or (S)-1,1-dimethylethyl 4-formyl-2,2-dimethyl-3-oxazolidinecarboxylate (7b), readily available from serine, react with Wittig reagents to give alkenes 8. Selective deprotection followed by oxidation of the resulting unsaturated amino alcohols 9 provides vinylglycines 5 of defined configuration (>95% ee) and double-bond geometry. D-Vinylglycines are obtained from L-serine, and conversely, D-serine gives β,γ-unsaturated amino acids with the L configuration. The double-bond geometry is controlled by the nature of the phosphorous ylide employed. The scope and limitations of this new methodology for the preparation of chiral vinylglycines is examined

Antiherpes peptide derivatives having a 1,4-dioxo-C4 N-terminus

Abstract: Disclosed herein are peptide derivatives of the formula R¹NH-CO-Q-C(O)-NR²-CH[CH₂C(O)-Y]-C(O)-NH-CH[CR³(R⁴)-COOH]-C(W)-NH-CHR⁵-Z wherein R¹ is an optionally substituted alkyl or optionally substituted phenylalkyl, R² is hydrogen or alkyl, R³ and R⁴ each independently is hydrogen or alkyl, or R³ and R⁴ are joined to form a cycloalkyl, R⁵ is alkyl, cycloalkyl or (cycloalkyl)alkyl, Q is a divalent radical, for example, -CH₂CH₂-, -CH=CH- or 1,2-cyclohexanediyl, which serves as a two carbon spacer, W is oxo or thioxo, Y is, for example, an alkoxy or a monosubstituted or disubstituted amino, and Z is a terminal unit, for example, hydrogen, COOH or CH₂OH. The derivatives are useful for treating herpes infections.

Preparation of 4-alkylprolines by intramolecular radical cyclization of chiral serine derivatives

Abstract: N-Alkylation of the β-lactone derived from Boc-L-serine followed by ring opening with sodium benzeneselenoate provides chiral substrates which undergo intramolecular radical cyclization to afford cis/trans mixtures of 4-alkyl-L-prolines.

Synthesis of Chiral Vinylglycines.

Abstract: (R)- or (S)-benzyl 4-formyl-2,2-dimethyl-3-oxazolidinecarboxylate (7a) and (R)- or (S)-1,1-dimethylethyl 4-formyl-2,2-dimethyl-3-oxazolidinecarboxylate (7b), readily available from serine, react with Wittig reagents to give alkenes 8. Selective deprotection followed by oxidation of the resulting unsaturated amino alcohols 9 provides vinylglycines 5 of defined configuration (>95% ee) and double-bond geometry. D-Vinylglycines are obtained from L-serine, and conversely, D-serine gives β,γ-unsaturated amino acids with the L configuration. The double-bond geometry is controlled by the nature of the phosphorous ylide employed. The scope and limitations of this new methodology for the preparation of chiral vinylglycines is examined