Motoyoshi Yamazaki

RING OPENING OF 2-ACYLAMINO-4,5-DIHYDRO-3-FURANCARBONITRILES BY USE OF TITANIUM (IV) CHLORIDE

The ring opening of 2-acylamino-4,5-dihydro-3-furancarbonitriles with titanium (IV) chloride gave the corresponding N-acyl-4-chloro-2-cyanobutanamides (I). On treatment with potassium carbonate, compounds I were converted to the corresponding N-acyl-1-cyanocyclopropanecarboxamides . On the other hand, the reaction of 2-benzamido-4,5-dihydro-3-thiophenecarbonitriles with titanium (IV) chloride gave the corresponding 2-benzamido-4,5-dihydro-3-thiophenecarboxamides.

Synthesis of 2H‐Thiopyrans by Rhodium(II) Acetate‐Catalyzed Reaction of 4‐Amino‐2,5‐dihydro‐3‐thiophenecarbonitriles with α‐Diazocarbonyl Compounds. Part 1

The reaction of 4-amino-2,5-dihydro-2- and -5-methyl-3-thiophenecarbonitriles with α-diazocarbonyl compounds in the presence of rhodium(II) acetate gave regioselectively 4-cyano-2H-thiopyrans (C2-S insertion) in moderate to good yields; 5-cyano-2H-thiopyrans (C5-S insertion) were not isolated. The starting compounds were synthesized by reaction of tetrahydro-2- and -5-methyl-4-oxo-3-thiophenecarbonitriles with morpholine, piperidine, and pyrrolidine in the presence of formic acid in ethanol.