Chemistry of 6H-pyrido[3,4-b]carbazoles. Part 6. The structure of some dihydropyridines derived from the addition of cyanide ion to 1-(N-methylacetamido)pyridinium salts and their further reactions

Abstract

Cyanide ion reacts with certain 3-(indol-3-ylformyl)-pyridinium salts to give 4-cyano-1,4-dihydro-adducts or ring-opened products depending upon the conditions. The former are easily aromatised to the corresponding 4-cyanopyridines and the reaction may be modified so that 2-cyanopyridines are formed, although in this case the intermediate adducts have not been identified. 3-(Indol-3-ylmethyl)pyridine-4-carbonitrile, when treated with dilute hydrochloric acid, gives 10H-pyrido[3′, 4′:4,5]cyclopent[1,2-b]indole.