RING-CHAIN TAUTOMERISM OF IMINE-AMINE OR KETONE-CARBINOL SYSTEMS OBTAINED BY CONDENSATION OF DILITHIO-N-SUBSTITUTED CARBOXAMIDES OR SULFONAMIDES WITH BENZONITRILE . SYNTHESIS OF CYCLIC PRODUCTS

Condensations of benzonitrile at the ortho position of N-substituted benzamides and N-substituted benzenesulfonamides were effected by means of n-butyllithium to form imine-amine, ring-chain tautomeric systems; in three of the four cases studied, the equilibrium was far on the side of the cyclic primary amines. All four of the primary amines were condensed with benzaldehyde to give corresponding benzal derivatives; also, the imine-amine product from N-methylbenzenesulfonamide and benzonitrile reacted with ethanol to give a cyclic ether-sulfonamide. The imine-amine, ring-chain products from the N-substituted benzenesulfonamides were hydrolyzed to afford ketone-carbinol, ring-chain systems, the equilibrium of which was far on the side of the ketone. Condensations of benzonitrile at the 2-methyl group of N-substituted o-toluenesulfonamides were effected by means of n-butyllithium, and the resulting mines were hydrolyzed to give corresponding ketone-carbinol, ring-chain tautomeric systems. Although the equilibrium wras on the side of the ketone, the cyclic carbinols were dehydrated to afford unsaturated cyclic sulfonamides, which are substituted benzothiazines. These double-bonded compounds underwent intramolecular β elimination with alkali amides in liquid ammonia to form corresponding acetylenic sulfonamides. Several new types of products were synthesized. © 1969, American Chemical Society. All rights reserved.