On the reaction of 2-(methylsulfonyl)quinoline with nucleophiles

Abstract

The ring-carbon in the 2-position of 2-(methylsulfonyl) quinoline (I) is active to nucleophilic reagents and the methylsulfonyl group is substituted (Chart 2). Application of the Grignard compound as the nucleophilic reagent resulted in the formation of 2-phenyl- or 2-alkyl-quinoline (VIII), but 2-quinolyl 2-quinolylmethyl sulfone (IX) was sometimes formed (Chart 3). Application of phenyllithium as the lithium compounds resulted in the formation of 2-phenylquinoline (VIIIa), as in the base of phenylmagnesium bromide, and IX. Reaction of I with pehnylacetonitrile in benzene, in the presence of sodium amide, afforded α-phenyl-2-quinolineacetonitrile (X) as would be expected from the result of reactions of (methylsulfonyl) benzodiazines. In the case of the reaction with ethyl malonate, products in which this ester had taken part were not obtained and only that with sodium amide, 2, 2'-iminodiquinoline (VII), was obtained. Reaction of I with ethyl cyanoacetate or with acetonitrile invariably gave bis (2-quinolyl) acetonitrile (XI), and a reaction with acetophenone gave the anticipated 2-(2-quinolyl) acetophenone (XII) (Chart 4 and 5). Finally, the reaction of I with ethyl cyanoacetate in dimethyl sulfoxide, in the presence of potassium cyanide, afforded quinaldonitrile (VI) and ethyl α-cyano-β-imino-2-quinolinepropionate (XIII), the latter assumed to have been formed by the addition of ethyl cyanoacetate to the -C=N group in VI (Chart 7).