Novel four-component route to the synthesis of spiro[indoline-3,4′-pyridine]-3′-carboxylate derivatives

An effective route to spiro[indoline-3,4'-pyridine]-3'-carboxylate derivatives is described. This involves reaction of isatin, 1-phenyl-2-(1,1,1-triphenyl-lambda(5)-phosphanylidene)-1-ethanone, and benzylamine derivatives or aliphatic amines in the presence of alkyl acetoacetate (1,3-dicarbonyl compounds) in dry methanol under reflux conditions. The reactive 1:1 enaminone, which is obtained from the addition of the amine to 1,3-dicarbonyl compound, adds to the alpha,beta-unsaturated ketone, which is formed from the reaction of isatin and 1-phenyl-2-(1,1,1-triphenyl-lambda(5)-phosphanylidene)-1-ethanone, to produce the alkyl l'-benzy1-2'-methy1-2-oxo-6'-phenyl-1'H-spiro[indoline-3,4'-pyridine]-3'-carboxylate derivatives in excellent yields. (c) 2011 Elsevier Ltd. All rights reserved.