Efficient Route to Benzo[4,5]imidazo[2,1‐a]phthalazines.

Abstract

Efficient Route to Benzo[4,5]imidazo[2,1-a]phthalazines. -A three-step synthesis of benzimidazophthalazines (IV) and (VIII) starts with the condensation of o-nitrophenylhydrazines (I) with o-carbonyl-substituted benzoic acid (II) followed by reduction of the nitro group and cyclization. The reduction and cyclization can be carried out in one pot using iron powder in hot phosphoric acid. A wide range of substituents at position 5 and 9 of the final product is introduced. -(KUZNETSOV, V. A.; SHUBIN*, K. M.; SCHIPALKIN, A. A.; PETROV, M. L.; Tetrahedron 62 (2006) 42, 10018-10030; Dep. Org. Chem., St. Petersburg State Inst. Technol., St. Petersburg 198013, Russia; Eng.) -Mischke 06-145