Synthesis, characterization and reactions of 2-deoxo-5-deazaalloxazines

5-Deazaflavins and their homologues. have been known as potential riboflavi n antagonists, bioreductives, and compounds with potent antitumor activity. 2-Amino-4-methylquinoline-3-carbonitrile (2) was prepared as unreported st arting material for several interesting 2-deoxo-5-deazalloxazine derivative s. Cyclization of 2 using formamide afforded the 2,4-deoxo-5-deazaalloxazin e derivative 7, which was subjected to deamination with nitrous acid to giv e the 2-deoxo-5-deazaalloxazine (8). The compound 8 was also obtained via 1 3 by treating the latter with refluxing formic acid or formamide and used a s a precursor for synthesis of several 2-deoxo-5-deazaalloxazines 18, 19, 2 0, 21 and 22. The pharmacological and biological properties of these compou nds are still under investigation. (C) 2001 Elsevier Science Ltd. All right s reserved.