Novel synthesis of fused phenazine derivatives containing biological interesting moieties

beta-(2-1H-Imidazo[4,5-b]phenazyl)acrylic acid 1 was prepared. Treatment of (1) with thionyl chloride and alcohols gave the corresponding esters 2a and 2b. The cyclization of acid I to the corresponding lactam, pyrrolo[1,5-a]imidazolo[4,5-b]phenazine-2-one 3 was investigated. Also fission of lactam to give the corresponding acid 1, hydrazide and N-phenylhydrazide (4a and 4b) and vinylene-bis-2,2'-imidazophenazine 5. Reaction of acid 1 esters 2a and 2b with primary aromatic amines gives 6a-d and 7a-b respectively. Reaction of esters 2a and 2b with hydrazines and hydroxylamine to give 4a-b and 8 has been discussed. Mean times the reaction of ester 2b with active methylene compounds to give 9-11 was described.