Purines, pyrimidines, and imidazoles. Part XXX. Some further syntheses of N-glycyl-D-ribofuranosylamine 5-phosphate (GAR) and N-(N-formylglycyl)-D-ribofuranosylamine 5-phosphate (FGAR), intermediates in the biosynthesis de novo of purine nucleotides

Abstract

Acylation of 2,3-O-isopropylideneribofuranosylamine 5-phosphate with N-benzyloxycarbonylglycyl chloride or p-nitrophenyl N-benzyloxycarbonylglycinate, in methanol or NN-dimethylformamide gave, after removal of protecting groups by hydrogenation and mild acid treatment, a mixture of the two isomeric (α- and β-) forms of N-glycyl-D-ribofuranosylamine 5-phosphate (GAR) which were separated by ion-exchange chromatography. Use of N-benzyloxycarbonylglycyl azide as an acylating agent gave only the enzymically inactive (α) form of GAR. The related N-(N-formylglycyl)-D-ribofuranosylamine 5-phosphate (FGAR) has been prepared in a similar manner by the reaction of the isopropylideneribofuranosylamine 5-phosphate with p-nitrophenyl N-formylglycinate. Relationships between the isomeric forms of GAR and FGAR are discussed.