REACTIONS OF METHYL 2-FORMYLFURO[3,2-B]PYRROLE-5-CARBOXYLATES

A series of hoxycarbonyl-4-R-furo[3,2-b]pyrrole-2-carbaldehyde 2,6-R(1 ),R(2)-phenylhydrazones and 5-methoxycarbonyl-4-R-furo[3,2-b]pyrrole N ,N-dimethylhydrazones were prepared from methyl 2-formyl-4-R-furo[3,2- b]pyrrole-5-carboxylates. By the reaction of the latter with hydroxyla mmonium chloride in acetic anhydride in the presence of pyridine methy l 2-cyano-4-R-furo[3,2-b]pyrrole-5-carboxylates were obtained. The rea ction of these compounds with sodium azide and ammonium chloride in di methylformamide led to methyl 2-(5'-tetrazolyl)-4-R-furo[3,2-b]pyrrole 5-carboxylates. The reaction of methyl 2-formyl-4-R-furo[3,2-b]pyrrol e-5-carboxylates with malononitrile afforded 5-methoxycarbonyl-4-R-fur o [3,2-b]pyrrol-2-ylidenemalononitriles, with methyl cyanoacetate meth yl xycarbonyl-4-R-furo[3,2-b]pyrrol)-2-yl]propenoates and with 2-furyl acetonitrile 3-[(5-methoxycarbonyl-4-R-furo[3,2-b]pyrrol)-2-yl] acrylo nitriles.