The studied 1-(2-benzothiazolyl)-2-pyridones Va-Vf were prepared from N-(2-benzothiazolyl)cyanoacetamide (II) which on reaction with 4-substituted benzaldehydes afforded 3-aryl-N-(2-benzothiazolyl)-2-cyano-2-propenamides IVa-IVg. Compounds IVa-IVf were cyclized with malonodinitrile in the presence of piperidine to give the corresponding pyridones Va-Vf.
Substituted 1-(6-methoxy-2-benzothiazolyl)-2-pyridones 5a-5f have been prepared from N-(6-methoxy-2-benzothiazolyl)cyanoacetamide (2) which on reactions with 4-substituted benzaldehydes gives 3-aryl-2-cyano-N-(6-methoxy-2-benzothiazolyl)-2-propenamides 4a-4g. Derivatives 4a-4f were cyclized with malonodinitrile in the presence of piperidine to give the corresponding 2-pyridones 5a-5f. The IR, UV, 1H NMR and mass spectra of the substances synthesized are discussed.
The reaction of 5-X-2-furaldehydes (X = C6H5, COOCH3, COOC2H5, C6H5O, C6H5S, CH3S, 4-Cl-C6H4S, CH3SO2, C6H5SO2, 4-Cl-C6H4SO2) with ethyl cyanoacetate in dry ethanol catalyzed by sodium ethoxide yielded the corresponding ethyl 2-cyano-3-(5-X-2-furyl)acrylates. It was found that the reactions of these esters with cyanoacetophenone or ethyl acetoacetate do not afford the corresponding 4H-pyran derivatives but that there proceeds the exchange of ethyl acetoacetate or of ethyl cyanoacetate for the cyanoacetophenone carbanion. The same course has been observed also for the reactions of these substrates with malononitrile.
Addition of a series of aromatic or aliphatic amines to 2,5-dimethyl-3-furoyl isothiocyanate (I) afforded the corresponding N-(2,5-dimethyl-3-furoyl)-N’-aryl- or alkylthioureas II or III. Spectral data (IR, UV, 1H NMR, 13C NMR and mass spectra) of compounds prepared are presented.
The 1,4-cycloaddition reaction of 4-phenyl-1,3-oxazole to 2-propinyl benzoate and dimethyl butinedioate afforded the respective 3-furylmethyl benzoate (I) and 3,4-bis(methoxycarbonyl)furan (II). These compounds served for the synthesis of 3-chloromethylfuran and 3,4-bis(chloromethyl)furan, which afforded via Wittig reaction 3-(β-arylvinyl)furans III (aryl = 5-nitro-2-furyl (IIIa), 5-nitro-2-thienyl (IIIb), 1-methyl-4-nitro-2-pyrrolyl (IIIc), and 4-nitrophenyl (IIIe)) and 3,4-bis(β-arylvinyl)furans IV (aryl = 5-nitrofuryl (IVa), 5-nitro-2-thienyl (IVc), and 4-nitrophenyl (IVd)). According to spectral evidence (1H NMR, IR, UV spectra), compound IIIa and IIIb originated as E isomers, whilst the remaining products are a mixture of E and Z isomers; some couples were succeded to separate.
Substituted 3-furylbenzoindolizines V-X were prepared via 1,3-dipolar cycloaddition of yields generated from the furan-related N-onium salts I-IV to dimethyl butinedioate, ethyl 3-(5-nitro-2-furyl)-2-propeonate, 1-phenyl-3-(5-nitro-2-furyl)-2-propenone, and 1-phenyl-2-nitroethylene. Structure of the compounds synthesized was confirmed by spectral data.
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