Abstract: | The Knoevenagel condensations of 5-3-(trifluoromethyl)phenyl]furan-2-carbaldehyde with seven compounds containing an active
methyl or methylene group have been studied. The compounds used were: methyl 2-cyanoacetate, malononitrile, 2-furylacetonitrile,
acetophenone, 2-thioxo-1,3-thiazolidin-4-one (rhodanine), 5,5-dimethylcyclohexane-1,3-dione (dimedone), and methyl 2-azidoacetate.
The effect of microwave irradiation on the condensation reactions was studied and compared with “’classical”’ conditions.
Thermolysis of methyl 2-azido-3-{5-3-(trifluoromethyl)phenyl]-2-furyl}propenoate afforded methyl 2-3-(trifluoromethyl)phenyl)]-4H-furo3,2-b]pyrrole-5-carboxylate.
(2E)-3-{ 5-3-(Trifluoromethyl)phenyl]-2-furyl}propenoic acid was converted to the corresponding azide, which was cyclized
on heating into 2-3-(trifluoromethyl)phenyl)]-4,5-dihydrofuro3,2-c]pyridin-4-one. The latter after successive action of
POCl3 and NH2NH2-Pd/C gave 2-3-(trifluoromethyl)-phenyl]furo3,2-c]pyridine.
Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 825–831, June, 2006. |