Phthalazino(2,3-b)phthalazine-5,12-dione prepn - by selective redn of phthalazino(2,3-b)phthalazine-5,7,12-trione

摘要

Anti-inflammatory phthalazino 2,3-b phthalazine-5(14H), 12(7H)-dione is prepd. by (a) reacting 2,3-dihydro-1,4-phthalazinedione with o-(halomethyl)benzoyl halide in the presence of an acid binder (esp. 2,4,6-trimethylpyridine) and (b) selectively reducing the 7-CO gp. of the resulting phthalazino 2,3-b phthalazine-5(14H), 7,12-trione with an alkali metal borohydride (esp. NaBH4), opt. in combination with a Gp. II or III metal halide (esp. CaCl2 or AlCl3), at 5-60 degrees C in a solvent consisting of DMF, dimethylacetamide, mixts. of DMF or dimethylacetamide with dioxan or THF, or THF or mixts. thereof with dioxan or lower dialkyl ethers of ethylene glycol.