Catalytic hydrogenation causes C-benzyl bond cleavage in 6-amino-7,7-dibenzyl-2,4-dimethoxy-7H-pyrrolo[3,2-d]pyrimidine: An example indicating novel route to 6-amino-7-benzyl-5H-pyrrolo-[3,2-d]pyrimidines and related compounds

Article abstract of DOI:10.1016/S0040-4020(98)83028-7

7-Benzyl-2,4-dimethoxy-5H-pyrrolo[3,2-d]pyrimidine (8) and 6-amino-7,7-dibenzyl-2,4-dimethoxy-7H-pyrrolo[3,2-d]pyrimidine (10) were prepared by reductive cyclization of the corresponding 6-(1-cyanoalkyl)-5-nitropyrimidines. Catalytic hydrogenation of compound 10 causes a C-C bond cleavage between carbon C-7 and one of the geminal benzyl groups. It leads to the formation of 6-amino-7-benzyl-2,4-dimethoxy-5H-pyrrolo[3,2-d]pyrimidine (12) which was spontaneously oxidized by air to 6-amino-7-benzyl-2,4-dimethoxy-7-hydroxy-7H-pyrrolo[3,2-d]pyrimidine (13).