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The reaction of 2-amino-4-(4-fluorophenyl)-4H-benzo[h]chromene-3-carbonitrile (3) with NN-dimethyldichlo-romethyleniminium chloride gave the tetracyclic chloro compound 4 which reacted readily with nucleophilic agents Such as morp...
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The reaction of 2-amino-4-(4-fluorophenyl)-4H-benzo[h]chromene-3-carbonitrile (3) with NN-dimethyldichlo-romethyleniminium chloride gave the tetracyclic chloro compound 4 which reacted readily with nucleophilic agents Such as morpholine, piperidine, methylpiperazine to afford 5a-c. Furthermore, displacement of the halogen atom Of Compound 4 by hydrazine yielded 5d. Compound 5d served as the precursor to pyranopyrimidine derivatives 6-11 by the reactions with triethyl orthoformate, NN-dimethyldichloromethyleniminium chloride, carbon disulfide, ethyl acetoacetate, ethyl cyanoacetate and sodium nitrite in acetic acid.
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A series of new 2-aryl-7-cyano/ethoxycarbonyl-6-methylthio-1H-imidazo[1,2-b]pyrazoles (5) have been synthesized in moderate to good yields, via a two-step cyclocondensation procedure of 5-amino-4cyano/ethoxycarbonyl-3-methylthio-1...
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A series of new 2-aryl-7-cyano/ethoxycarbonyl-6-methylthio-1H-imidazo[1,2-b]pyrazoles (5) have been synthesized in moderate to good yields, via a two-step cyclocondensation procedure of 5-amino-4cyano/ethoxycarbonyl-3-methylthio-1H-pyrazole (1) and alpha-bromoacetophenones (3) or alpha-tosyloxyacetophenones (2), which were prepared by the reactions of acetophenones with [hydroxy(tosyloxy)iodo] benzene (HTIB). The intermediates, 5-amino-1-(aroylmethyl)-4- cyano/ethoxycarbonyl-3-methylthio-1H-pyrazoles (4), have been isolated, serving as evidence for the regioselectivity. When utilizing alpha-tosyloxy-acetophenones, the reactions were more eco-friendly, the reaction time was significantly reduced and the synthetic procedure was more convenient and easier to manipulate. Surprisingly, using potassium carbonate to displace sodium carbonate in the synthesis of 4, in the case of 1 (R= CN), two novel cyclocondensation products have been isolated and fully characterized, followed by the proposal of a plausible mechanism.
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1,3,5-Trisubstituted pyrazolines (1a-i) undergo facile oxidation to the corresponding pyrazoles (2a-i) In the presence of iodobenzene diacetate. [References: 17]
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2,2-Difluorovinyl ketones 1 react with monosubstituted hydrazines to afford 5-fluoropyrazoles in a regioselective manner via replacement of the fluorine by the substituted nitrogen of the hydrazines and dehydration between the car...
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2,2-Difluorovinyl ketones 1 react with monosubstituted hydrazines to afford 5-fluoropyrazoles in a regioselective manner via replacement of the fluorine by the substituted nitrogen of the hydrazines and dehydration between the carbonyl group of 1 and the NH2 end. The reactions are successfully effected for both aliphatic and aromatic hydrazines in aqueous ethanol under neutral conditions and in THF under basic conditions with butyllithium, respectively. A similar ring-forming reaction of 1 with hydrazine monohydrate is induced by the addition of trifluoroacetic acid to give N-unsubstituted 3-fluoropyrazoles, which in turn react with alkyl and aryl halides in the presence of sodium hydride, leading to a regiocontrolled synthesis of 3-fluoropyrazoles. [References: 37]
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The polarographic and cyclic voltammetric reductions of the three isomeric nitrobenzaldehydes in molten acetamide are investigated. Nitrobenzaldehydes exist in two forms in this melt. The aldehyde group is solvated by acetamide, a...
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The polarographic and cyclic voltammetric reductions of the three isomeric nitrobenzaldehydes in molten acetamide are investigated. Nitrobenzaldehydes exist in two forms in this melt. The aldehyde group is solvated by acetamide, and there exists an equilibrium between the free nitrobenzaldehyde and the acetamide-solvated nitrobenzaldehyde. The kinetics of solvation is dependent on the acid-base conditions of the melt, temperature of study, and position of the aldehyde group. [References: 26]
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New peptidic componds,having peptide chains linked to bi-and tricyclic heteorcycles (peptide-heterocycle hybrids),have been synthesized.The heterocyclic components are derivatives of partially reduced isoquinoline and pyridol[1,2-...
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New peptidic componds,having peptide chains linked to bi-and tricyclic heteorcycles (peptide-heterocycle hybrids),have been synthesized.The heterocyclic components are derivatives of partially reduced isoquinoline and pyridol[1,2-b]isoquinoline bearing alpha,beta-unsaturated carbonyl functionalities.The heterocyclic compounds have been used as acylating agents in coupling reactions with short N-unprotected peptides.Basedonour interest onpotential calpain inhibitors,we have used short (2-4 amino acids) peptides with hydrophobic amino acids of the two enantiomeric series.Wereport preliminary studies on the inhibition of calpain,with some compounds having IC_(50) values in the nanomolar range.
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Reaction of several Vilsmeier reagents with 5-amino-2,3-dihydro[1]benzofuro[3,2-b]oxepin-4-carbonitrile gave tetracyclic 2-substituted 4-chloro-5,6-dihydro[1]benzofuro[3′,2′:2,3]oxepino[4,5-d]pyrimidines. The structure of one of...
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Reaction of several Vilsmeier reagents with 5-amino-2,3-dihydro[1]benzofuro[3,2-b]oxepin-4-carbonitrile gave tetracyclic 2-substituted 4-chloro-5,6-dihydro[1]benzofuro[3′,2′:2,3]oxepino[4,5-d]pyrimidines. The structure of one of these, the 4-chloro-2-phenyl derivative, was confirmed by X-ray crystallography. Treatment of the 4-chloro derivatives with simple amines as nucleophile afforded 2-substituted 4-amino derivatives. A pentacyclic compound was also obtained by dehydrative ring closure. These products were evaluated for antiplatelet activity, and some showed potency comparable with that of aspirin.
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Four new 2-thiohydantoin derivatives (4a-d) were synthesized from the reaction of maleimide derivatives (3a-d) with phenylisothiocyanate. The structures of synthetic compounds were characterized using Fourier-transform infrared sp...
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Four new 2-thiohydantoin derivatives (4a-d) were synthesized from the reaction of maleimide derivatives (3a-d) with phenylisothiocyanate. The structures of synthetic compounds were characterized using Fourier-transform infrared spectroscopy (FT-IR), 1H- and 13C-nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry. The antioxidant activity of the synthesized compounds showed inactive 4b and 4c compounds, moderately active 4a, and strongly active 4d, compared with vitamin C as positive control (IC50 values = 1.380, 1.726, 4.147, 8.085, and 9.826 μM, respectively). Antibacterial and antifungal activities of compounds showed that only compound 4b had an effect on Pseudomonas aeruginosa, Candida albicans, and Aspergillus niger species.
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摘要 :
Treatment of 2-substituted 4-chloro-5,6-dihydro[1]benzofuro[30,20:2,3]oxepino[4,5-d]pyrimidines with simple alcohols and thiols as nucleophile afforded 2-substituted 4-alkoxy (or sulfanyl) derivatives. In the case of alkoxide nucl...
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Treatment of 2-substituted 4-chloro-5,6-dihydro[1]benzofuro[30,20:2,3]oxepino[4,5-d]pyrimidines with simple alcohols and thiols as nucleophile afforded 2-substituted 4-alkoxy (or sulfanyl) derivatives. In the case of alkoxide nucleophiles, rearranged reaction products were also obtained. X-ray crystallography was used to support the structure assignment of the rearranged product.
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The Lewis acid catalyzed synthesis and chromatographic purification of isatoic anhydride-derived 2- (20-anilinyl)-1,3-benzoxazole (2) can result in the co-isolation of 2 and a light pink colored impurity (<5%). This latter species has been identified (NMR, single crystal X-ray diffraction, mp) as 20- hydroxy-2-aminobenzanilide (3), which represents a predictable intermediate in the formation of 2. Compound 3 crystallizes in an orthorhombic crystal system of space group P212121 with four molecules in the unit cell (a = b = c = 90; a = 6.715 (2) A , b = 12.100 (4) A , c = 13.321 (4) A ; V = 1082.2 (6) A 3). Pure 2 is characterized as a colorless, high-melting solid; unlike the dark colored oil that is isolated if 2 contains traces of 3....
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The Lewis acid catalyzed synthesis and chromatographic purification of isatoic anhydride-derived 2- (20-anilinyl)-1,3-benzoxazole (2) can result in the co-isolation of 2 and a light pink colored impurity (<5%). This latter species has been identified (NMR, single crystal X-ray diffraction, mp) as 20- hydroxy-2-aminobenzanilide (3), which represents a predictable intermediate in the formation of 2. Compound 3 crystallizes in an orthorhombic crystal system of space group P212121 with four molecules in the unit cell (a = b = c = 90; a = 6.715 (2) A , b = 12.100 (4) A , c = 13.321 (4) A ; V = 1082.2 (6) A 3). Pure 2 is characterized as a colorless, high-melting solid; unlike the dark colored oil that is isolated if 2 contains traces of 3.
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