Efficient synthesis of new 1-[Alkyl(aryl)]-5-(3,3,3-trihalo-2-oxopropylidene)pyrrolidin-2-ones

reactions of methyl 4-methoxy-6-oxo-7,7,7-trihalo-4-heptenoates 1 and 2 with primary amines rnh2, where r = phch2, phch2ch2, ph, 4-mec6h4, 4-meoc6h4, 4-clc6h4, 4-brc6h4, 2-pyridyl, 5-methyl-3-isoxazolyl, 4-nh2c6h4 affording methyl 4-[alkyl(aryl)amino]-6-oxo-7,7,7-trihalo-4-heptenoates 3, 4, in good yields (57-95%), which suffer quantitative intramolecular cyclocondensation to produce 1-alkyl(aryl)-5-(2-oxo-3,3,3-trihalopropylidene)pyrrolidin-2-ones 5, 6, are reported. the structures of the isolated new products were assigned by means of 1h, 13c nmr measurements and mass spectrometry. the z and e configuration of compounds 3d and 5b respectively were established from x-ray crystallography.