Studies with enaminones: Synthesis of new cournarin-3-yl azoles, cournarin-3-yl azines, coumarin-3-yl azoloazines, coumarin-3-yl pyrone and coumarin-2-yl benzo[b]furans
Fmaa. El-taweel et Mh. Elnagdi, Studies with enaminones: Synthesis of new cournarin-3-yl azoles, cournarin-3-yl azines, coumarin-3-yl azoloazines, coumarin-3-yl pyrone and coumarin-2-yl benzo[b]furans, J HETERO CH, 38(4), 2001, pp. 981-984
3-Acetylcoumarine was condensed with dimethylformamide dimethylacetal (DMFD
MA) to yield the enaminone, which reacts readily with hydroxylamine and wit
h hydrazines to yield coumarin-3-ylisoxazoles and coumarin-3-ylpyrazoles re
spectively. Reaction of the enaminone with benzamidine hydrochloride and 3-
amino-1,2,4-1H-triazole affords the pyrimidine and triazolo[3,4-b]pyrimidin
e. The enaminone reacts with hippuric acid and with the dithiocarboxylic ac
id to yield pyranones. The reaction of the enaminone with 3-amino-1H-1,2,4-
triazole gives the triazolo[3,4-b]pyrimidine. The enaminone underwent self
dimerization on reflux in acetic acid ammonium acetate to yield the coumari
nyl pyridines and reacted with ketone under the same conditions to yield th
e pyridine. The reaction of the enaminone with 1,4-benzoquinone and 1,4-nap
hthoquinone gives benzofuryl coumarine derivatives.