Cyclic amidines. Part XXIII. Dibenzo[b,h][1]benzopyrano[2,3,4-de][1,6]naphthyridines and their molecular orientation in carcinogenesis

Abstract

Cyclisations of substituted dibenzo[b,h][1,6]naphthyridines and of substituted [1]benzopyrano[3,2-c]quinolin-7-ones, and the condensation of N-carboxyanthranilic acid anhydrides with substituted 1,3-diphenylpropane-1,3-diones followed by a reductive cyclisation leading unequivocally to dibenzo[b,h][1] benzopyrano[2,3,4-de][1,6]naphthyridine and five isomeric methyl derivatives, are described. An explanation is given of the differences in carcinogenic activity of the 2-, 7-, and 12-methyl derivatives, consistent with specific molecular orientations for carcinogenesis similar to those deduced for tricycloquinazoline and its derivatives.