Studies in the carbazole and pyridobenziminazole series

Abstract

An examination of the ultra-violet absorption spectra and the dehydrogen&tlon of the products obtained by condensation of 2-aminopyrldine and its derivatives with 2-chlorocyclohexanone has shown that these compounds are derivatives of the cyclic diazalihe, Pyrido (l'i 2's 1 5 2)-benziminazole, and not of 2-Carboline as stated in a Patent dealing with this condensation* The preparation of 2-(2f-Pyridylamino) ■ cyclohexanone, the intermediate amino ketone in this condensation, by condensing the reactants in the presence of sodium carbonate has shown that it is not necessary to prepare compounds of this type by isolation of the sodium derivative of 2-aminopyridine* The cyclodehydration of this intermediate to Pyrido (l'j 2's 1 i 2)4 ! 5 i 6 s /-tetrahydrobenziminazole has been found to be an acid catalysed reaction, but the mechanism of the direct reaction in which hydrochloric acid and water are split out simultaneously remains unsolved.Several new members of the pyriminazole series have been prepared, and in two eases their absorption spectra determined and compared with that of 2-methyl4 7-azaindole.