One pot synthesis of pyridine, thiazolidine, pyrazole and 2, 3-dihydro-1, 3, 4-thiadiazole derivatives under solvent-free condition

Claisen condensation of 2-acetylbenzofuran and 1,3-diphenyl-1H-pyrazole-4-carbaldehyde 2 gave chalcone 3 which was exploited as a starting material for the syntheses of hitherto unknown different types of new heterocyclic compounds incorporating the benzofuran moiety via the reaction with various active methylene compounds. On the other hand, several new thiadiazolines, pyrazoles and pyrazolo[3,4-d]pyridazine were synthesized by the reaction of 3-(benzofuran-2-yl)-3-oxopropanenitrile 12 with?-halo ketone, ?-halo ester and hydrazonoyl halides.