One- or Two-Step Synthesis of C-8 and N-9 Substituted Purines

摘要

A novel and original strategy to obtain rapidly a large diversity of C-8 and N-9 substituted purines was developed. The present procedure describes annulation reactions in one or two steps starting from 5-aminoimidazole-4-carbonitriles 1 – 8 in moderate to good yields. 8,9-Disubstituted-6,9-dihydro-1 H -purin-6-ones 9 – 14 , 6-amino-8,9-disubstituted-3,9-dihydro-2 H -purin-2-ones 15 – 20 , 8,9-disubstituted-3,9-dihydro-2 H -purin-2,6-diamines 21 – 24 and 6-imino-1-phenyl-8,9-disubstituted-6,9-dihydro-1 H -purin-2-(3 H )-ones 25 – 26 were synthesized in one step using formic acid, urea, guanidine carbonate, and phenylisocyanate, respectively, whereas 8,9-disubstituted-9 H -purin-6-amines 27 – 31 and 6-imino-8,9-disubstituted-6,9-dihydro-1 H -purin-1-amines 32 – 33 were obtained in two steps using formamide and hydrazine, respectively.