SYNTHESIS OF L-1,2-DIHYDRO-7H-IMIDAZO[1,2,3-CD]PURINE-6,8-DIONE OR L-1,2-DIHYDRO-7H-IMIDAZO[1,2,3-CD]PURINE-6,8-DIONE

New 4-alkyl- or -1,2-dihydro-7H-imidazo[1,2,3-cd]purine-6,8-diones 1 w ere obtained by intramolecular alkylation of 8-alkyl- or esyloxyethyl) -1-methyl-9H-purine-2,6(1H,3H)-diones 5. The necessary compounds 5 wer e prepared from roxyethyl)amino]-3-methyl-5-nitrosopyrimidine-2,4( 1H, 3H)-dione (2), which was hydrogenated to 5-amino-6-[(2-hydroxyethyl)am ino]-3-methyl derivative 3; consecutive reactions of the latter with a n orthocarboxylate and mesyl chloride afforded 8-alkyl- or hydroxyethy l)-1-methyl-9H-purine-2,6(1H,3K)-diones 4 and compounds 5, respectivel y.