SYNTHESIS OF OPTICALLY ACTIVE 9-PURINYL-α-AMINO ACIDS
A general method for the synthesis of optically active 9-purinyl-α-amino acids by condensation of 5-amino-4,6-dichloropyrimidine with α,ω-diamino carboxylic acids and subsequent cyclization of the Nω-(5-amino-4-chloro-6-pyrimidinyl)-amino acids with triethyl orthoformate was developed.A number of 6-substituted α-amino-ω-(9-purinyl)carboxylic acids were obtained by nucleophilic substitution of the chlorine atom in the α-amino-ω-(6-chloro-9-purinyl)carboxylic acids.