Synthetic studies on the synthesis of pyridine, alpha-pyran, alpha-thiopyran, and thienothiopyranopyrrol derivatives using PTC technique

The reaction of p-chlorophenylmethylenemalononitrile 1 with some reactive h alo compounds under phase-transfer catalysis conditions (PTC) afforded the corresponding alkylated or cyclized products 2-9 Thienothiopyranopyrrol 12( a-c) were synthesized from the reaction of compound 1 or 4 with CS2 and eth yl chloroacetate in 1:1:2 molar ratio via the formation of the intermediate s thiopyrans 10(a-c) and theinothiopyrans 11(a-c). Also, compound 1 or 4 re acted with phenylisocyanate or phenylisothiocyanate to give a-pyran, alpha -thiopyran pyridinone, and pyridine-2-thione derivatives 13-16, respectivel y. The sequence of the reactions was studied.