No abstract

Isatin reacted with diethyl 3-amino-2-cyano-2-pentenedioate in ethanol and in presence of Et3N to give 3-(1-amino-2-cyano-2-ethoxycarbonylethenyl-2H-furo[2,3-b]indol-2-one. The reaction of (2-oxo-3-indolinylidene)malononitrile (3a) with the diethyl ester gave a mixture of diethyl 3-amino-4-(2-amino-3-cyano-4-quinolylcarbonyl)-2-cyano-2-pentenedioate (80%) and diethyl 3-amino-4-(2-amino-3-cyano-3aH-furo[2,3-b]indol-3a-yl)-2-cyano-2-pentanedioate (20%). Treatment of 3a and 3-[cyano(ethoxycarbonyl)]methylene-2-indolinone (3b) with 2-(ethoxycarbonylmethyl)-2-thiazolin-4-one gave the corresponding two pyrano[4′,5′-c] and furo[2″,3″-b]indole compounds, respectively. When 3a and 3b also reacted, with 3-methyl-2-pyrazolin-5-one or 3-methyl-1-phenyl-2-pyrazolin-5-one, the corresponding four spiro indoline-3,4′-(1′H)-pyrano[2,3-c]pyrazol products were obtained. The reaction of 3b with benzoylacetonitrile gave ethyl 2-amino-3a-[benzoyl(cyano)methyl]-3aH-furo[2,3-b]indole-3-carboxylate.

Starting with 4‐aminoacetophenone (I), the heterocycles (V), (XII), and (XIV) mentioned in the title are prepared by condensation reactions as outlined in the reaction scheme.

Thermolysis and photolysis of benzohydroxamic acid and some of its derivatives have been investigated. Thermolysis of benzohydroxamic acid (BHA) either by heating in air or in a sealed tube gives NH3, H2O, CO, benzil, aniline, o- and p-aminophenols, phenoxazine, benzanilide, and benzoic acid. Whereas, thermolysis of N-(benzyloxy)benzamide (BBA) affords toluene, benzaldehyde, bibenzyl, stilbene, phenanthrene, acridine, and o- and p-aminodiphenylmethane in addition to the previous products. Analogous products were also obtained on pyrolysis of phenylacetohydroxamic acid. Photolysis of BHA and BBA in acetonitrile gives similar results to those of pyrolysis. A free-radical mechanism involving homolysis at different sites was postulated to account for the formation of such products.

Thermolysis of benzophenone O-benzoyloxime leads to the formation of NH3, CO2, benzene, biphenyl, benzophenone, benzanilide, benzonitrile, benzoic acid, 2-phenylbenzoxazole, salicylaldehyde and its p-isomer. Analogous results were also obtained on thermolysis of acetophenone O-benzoyloxime. Similarly, benzophenone and/or acetophenone O-benzyloximes give pyrolysis products of the same nature in addition to others corresponding to the benzyl moiety. Thermolysis of deoxybenzoin oxime gives NH3, toluene, benzonitrile, bibenzyl, benzil, benzyl alcohol, and 2-phenylindole. Moreover, its O-benzoyl ether affords in addition to these products, benzoic acid and benzyl benzoate. The main feature of these pyrolyses is the homolysis of the N–O bond together with either O-benzyl or O-benzoyl bonds providing free radicals that undergo different reactions involving H-abstraction, dimerization, fragmentation, rearrangement and cyclization to form the identified products.