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3,5-Di(m- and p-tolyl)-1,2,4-triazples were obtained by reaction of formalin with 2,5-ditolyl-1,3,4-oxadiazoles and subsequent hydrolysis of the resulting formyl derivatives. 3,5-Di(o-tolyl)-1,2,4-triazole cannot be obtained by this method. The oxidation of 3,5-ditolyl-1,2,4-triazoles leads to 3,5-bis(carboxyphenyl)-1,2,4-triazoles, which were converted to diesters and dihydrazides.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 848–849, June, 1978.  相似文献   
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We consider a quadratic d. c. optimization problem on a convex set. The objective function is represented as the difference of two convex functions. By reducing the problem to the equivalent concave programming problem we prove a sufficient optimality condition in the form of an inequality for the directional derivative of the objective function at admissible points of the corresponding level surface.  相似文献   
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Reactions of new enehydrazides, N',N'-dimethyl-N-vinylpropenohydrazide and N',N'-dimethyl-N-vinylbenzohydrazide with chloroform, phenol, and hydrogen chloride in carbon tetrachloride were studied by IR spectroscopy. In the first two cases, molecular complexes are formed between the hydrazide and proton donor. The reaction of N',N'-dimethyl-N-vinylpropenohydrazide with HCl results in formation of dihydropyrazole derivative which exists as a tautomeric mixture of the major lactam and minor lactim forms. N',N'-dimethyl-N-vinylbenzohydrazide reacts with hydrogen chloride to give protonated form in which proton is localized on the amino nitrogen atom. The structure of the initial compounds and the products was analyzed in terms of AM1 quantum-chemical calculations.  相似文献   
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Abstract Lyophilized aged garlic extract has been incorporated at concentrations of 0.1%, 1% and 4% by weight into semipurified powdered diets and fed to hairless mice. Under moderate UVB exposure conditions resulting in 58% suppression of the systemic contact hypersensitivity response in control-fed mice, a dose-responsive protection was observed in the garlic-fed mice; contact hypersensitivity in the UVB-exposed mice fed 4% garlic extract was suppressed by only 19%. If the UVB exposure was replaced by topical application of one of a series of lotions containing increasing concentrations of cis -urocanic acid, a dose-responsive suppression of contact hypersensitivity was demonstrated in control-fed mice (urocanic acid at 25, 50, 100 and 200 μg per mouse resulting in 22–46% suppression). Mice fed a diet containing 1% aged garlic extract were partially protected from cis -urocanic acid-induced suppression of contact hypersensitivity, with greater protection from the lower concentrations of urocanic acid. Mice fed a diet containing 4% aged garlic extract were protected from all concentrations of urocanic acid. The results indicate that aged garlic extract contains ingredient(s) that protect from UVB-induced suppression of contact hypersensitivity and suggest that the mechanism of protection is by antagonism of the cis -urocanic acid mediation of this form of immunosuppression.  相似文献   
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1,2,4-Triazoles with symmetrical tolyl substituents were obtained from the corresponding 1,3,4-oxadiazoles by reaction with formamide and subsequent hydrolysis of the resulting formyl derivatives; 1,2,4-triazoles with unsymmetrical substituents were obtained from iminoesters and hydrazides of acids. A set of bands of the triazole ring at 1470–1480, 1390, 1270–1290, 1140–1150, and 725–750 cm–1 and of NH vibrations at 2400–3200, 1580–1620, and 830–900 cm–1 are characteristic for the IR spectra of these triazoles. The UV spectra of the triazoles are characterized by phenyl ring absorption at about 200 nm and a band of electron transitions between the phenyl and triazole rings at 230–290 nm.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1682–1685, December, 1977.  相似文献   
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