Synthesis of Bredinin from 1-β-D-Ribofuranosyl-5-aminoimidazole-4-carboxamide by a Photo-Reaction.

Photolysis of 1-β-D-ribofuranosyl-5-aminoimidazole-4-carboxamide (AICA-riboside) gave 2-amino-N-(β-D-ribofuranosyl)malondiamide, which was cyclized by treatment with ethyl orthoformate to furnish 1-β-D-ribofuranosyl-5-hydroxyimidazole-4-carboxamide (bredinin), a potent immunosuppressive nucleoside antibiotic.