AFINIDAD, PART IV, REACTIONS WITH COUMARI N - SYNTHESIS AND REACTIONSOF COUMARIN SULFONAMIDES

Coumarin-6-sulphonyl chloride 1 was amidated with different secondary amines to give a. Compounds 2a-d with hydrazine under controlled condi tions effected ring-opening of the lactone ring to afford the correspo nding o-hydroxycinnamoyl hydrazides 3a-d. Hydrazones 4 and 5 were obta ined by condensation of 3a or 3c with the appropriate aldehyde. Compou nds 4b and 5b were cyclized using acetic anhydride to yield the oxadia zolines 6a,b; respectively. Reaction of hydrazide 3a or 3c with 4-tolu oyl chloride afforded the corresponding N-toluoyl derivative 7a or 7b, which cyclized with POCl3 to the corresponding 1,3,4-oxadiazole deriv atives 8. The thiosemicarbazide derivatives 9 were obtained by treatme nt 3a or 3c with phenylisothiocyanate. Cyclization of 9 using POCl3 af forded the corresponding 1,3,4-thiadiazoles 10.