Reactions with coumarin: synthesis and reactions of coumarin sulfonamides.
Abdel-Bary, Hamed M.
Afinidad, 55 (1998) 67-71.
Abstract
Coumarin-6-sulfonyl chloride was aminated with different secondary amines to give the sulfonamides. Treatment of these with hydrazine under
controlled conditions effected ring-opening of the lactone ring to afford the corresponding o-hydroxycinnamoyl hydrazides which were converted to
hydrazones by reation with various aldehydes. The hydrazones were cyclized using acetic anhydride to yield oxadiazolines. Reaction of the hydrazides
with 4-toluoyl chloride afforded the corresponding N-toluoyl derivs. which cyclized with POCl3 to the corresponding 1,3,4-oxadiazole derivs.
Thiosemicarbazide derivs. were obtained by treatment of the hydrazides with PhNCS. Cyclization of the thiosemicarbazides using POCl3 afforded the
corresponding 1,3,4-thiadiazoles. |