【文章名】Transformation of 1,5-diphenylpentane-1,3,5-trione. The synthesis of substituted (4H)-pyranones, pyridin-4(1H)-ones and 4H-pyrano[3,2-c]pyridin-4-ones.
Transformation of 1,5-diphenylpentane-1,3,5-trione. The synthesis of substituted (4H)-pyranones, pyridin-4(1H)-ones and 4H-pyrano[3,2-c]pyridin-4-ones.
[摘要]：1,5-Diphenylpentane-1,3,5-trione (I) was transformed by the reaction either with N,N-dimethylformamide di-Me acetal (DMFDMA) or N,N-dimethylacetamide di-Me acetal (DMADMA) into (N,N-dimethylamino)methylidene derivs. 2a,b as intermediates. They were converted in the presence of silica gel into 5-benzoyl-2-phenylpyran-4-one and its 6-Me deriv. (II), while the corresponding 5-benzoyl-2-phenylpyridin-4(1H)-one was formed by the reaction with NH4Cl. Compd. II gave the corresponding (N,N-dimethylamino)methylidene deriv. with DMFDMA, which was cyclized in aq. ammonia into 2,5-diphenyl-4H-pyrano[3,2-c]pyridin-4-one. The reaction of I with excess of DMFDMA followed by reaction with ammonia or primary amines yielded 1-substituted 3,5-dibenzoylpyridin-4(1H)-ones.
