Toshihiro Matsuzawa

A practical synthesis of antiviral cyclopropane nucleoside A-5021

Abstract (1′ S ,2′ R )-9-[[1′,2′-bis(hydroxymethyl)cycloprop-1′-yl]methyl]guanine (A-5021, 1 ) was synthesized from optically active cyclopropane lactone 2 by employing: (1) selective reduction of the ester; (2) alkylation of 2-amino-6-chloropurine; and (3) reductive opening of the lactone ring. This route eliminates the protection steps to give 1 in a good yield and is of practical value.