Synthesis of 3‐(3‐pyridyl)‐ and 3‐(3‐benzo[b]thienyl)‐D‐alanine

Abstract

The DL‐arylamino acid ethyl ester derivatives of β‐(3‐pyridyl)‐DL‐alanine, and β‐(3‐benzo[b]thienyl)‐DL‐alanine were synthesized by diethyl acetamidomalonate condensation with the respective arylmethyl halides followed by partial hydrolysis to the monoethyl ester and decarboxylation. Each derivative was enzymatically resolved to a separable mixture of the corresponding N‐acetyl‐L‐amino acid and the unchanged D amino acid derivative. Acidic hydrolysis of the latter gave the corresponding D‐amino acid, the optical purity of which was established by HPLC analysis of the 2,3,4,6‐tetra‐O‐acetyl‐β‐D‐glucopyranosyl isothiocyanate (GITC) derivative. The free D amino acids were converted to D‐BOC derivatives by reaction with di‐tert‐butyldicarbonate in tert‐butyl alcohol, water and sodium hydroxide.

Synthesis, crystal structure, and coordination properties of a helical peptide having β-(3-pyridyl)-l-alanine and l-glutamic acid residues

“…The optically active Pal amino acid was prepared by hydrogenation of N-acetyl-b-(3-pyridyl)-a,b-dehydroalanine, which was obtained from N-acetyl-glycine and pyridine-3-aldehyde, followed by acylase-catalyzed enzymatic resolution [24][25][26]. Boc amino acids were prepared by standard procedure using di-tert-butyl dicarbonate, (Boc) 2 O [27,28].…”