Carcinogenic nitrogen compounds. Part LXXXIII. New condensed acridines derived from benz[c]indeno[1,3-mn]-, benz[c]indeno[1,3-kl]-, and phenanthro[9,10,1-mna]-acridines

7-o-Chlorophenyl-5-methylbenz[c]acridine underwent cyclisation with sodium hydroxide in benzo[h]quinoline to give a mixture of 14-methylbenz[c]indeno[1,3-kl]- and 9-methylbenz[c]indeno[1,3-mn]-acridine, and a similar reaction with 7-o-chlorophenyl-5,9-dimethyldibenz[c,h]acridine gave 5,11-dimethyldibenz[c,h]indeno-[1,3-kl]acridine. In both cases, by-products were isolated. 2-Methylphenanthro[9,10,1-mna]acridine was obtained from 12-(2-chloro-5-methylphenyl)benz[a]acridine, but the 6-methyl isomer did not cyclise. Some methyl-substituted 14-o-chlorophenyldibenz[a,h]- and -dibenz[a,j]-acridines furnished the corresponding 1-azapyrenes.