The synthesis of some new derivatives of 1, 7-dimethylxanthine

We have synthesized a group of new 8-substituted 1, 7-dimethylxanthines which are of interest for biological investigation as very close structural analogs of some 8-substituted theobromine derivatives obtained previously. In particular, we have carried out the conversion of 8-hydroxymethyl-1, 7-dimethlxanthine (I) [1] into 8-chloromethyl-1, 7-dimethylxanthine (II) and from this, by heating it for 6 hours with an excess of diethylamine or by condensing it with sodioacetylaminomalonic ester in ethanol we have obtained 8-diethylaminomethyl-1, 7-dimethylxanthine (III) and its hydrochloride (compare [2]) or 8-(-acetylamino-, -diethoxycarbonylethyl)-1, 7-dimethylxanthine (IV). The hydrolytic cleavage of the latter, accompanied by partial decarboxylation, led to 1, 7-dimethyl-8-xanthinylalanine (V) (cf. [3]).     

A Kinetic Model for the Epoxidation of Allyl Alcohol with Hydrogen Peroxide on Titanium Silicate TS-1

The kinetic regularities of the oxidation of allyl alcohol into glycidol in the presence of titanium silicate are studied at varied initial concentrations of the reagents, products, and temperature. The probable mechanism is used as the basis to develop a substantial kinetic model, which adequately describes the obtained experimental data.     

Stability in Generalized Differentiability Based on a Set Convergence Principle

In this paper, we are concerned with epiconvergent sequences of nonsmooth functions. From a general principle of upper set convergence of set-valued maps we derive stability results for various objects in generalized differentiability. In particular, we establish stability results for the Clarke generalized gradient of locally Lipschitz functions, respectively for the generalized Hessian of C ^1,1 functions.      

Method of calculating steady-state flows of a viscous fluid with free boundary in vortex-stream function variables

Computations of the motion of a viscous incompressible fluid with a free boundary in vortex-stream function variables entail difficulties in the implementation of boundary conditions on the free surface. A new approach to the formulation of boundary conditions, which takes into account the specifics in giving these conditions on the free boundary is proposed. An efficient numerical method of calculating steady-state flows of a fluid is developed and implemented. Model computations for problems that have exact solutions are performed. Lavrent'ev Institute of Hydrodynamics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 39, No. 2, pp. 59–68, March–April, 1998.     

Investigation of lactams

2,3,4-Trioxohexahydroazepine 4-phenylhydrazone with a ¹⁵N-labeled atom bonded to the phenyl fragment was obtained in order to establish its structure. It was established by means of the PMR spectra that this substance is a mixture of syn and anti isomers of the hydrazone form. 2,3,4-Trioxohexahydroazepine 3-phenylhydrazone was isolated when an attempt was made to indolize the 4-phenylhydrazone. Both hydrazones react with phenylhydrazine to give the same 2,3,4-trioxohexahydroazepine 3,4-bis(phenylhydrazone). Derivatives involving the carbonyl group were obtained for both hydrazones, and the conditions for their indolization were studied, as a result of which a number of azepino[4,5-b]indole derivatives were synthesized.See [1] for communication 32.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 954–960, July, 1979.     

State of Silicotungstic Acid in Aqueous Solutions in the Presence of Inorganic Salts as Probed by NMR Spectroscopy

The state of silicotungstic acid (STA) in the presence of inorganic salts (Fe₂(SO₄)₃, SnCl₂, and SnSO₄) in aqueous solutions was studied by ¹⁸³W NMR spectroscopy. Silicotungstic acid was found to retain its structure, and no new heteropoly compounds were formed. This finding proves the enhanced stability of STA toward complex formation at high acidities.     

Effect of technological parameters on the process of epichlorohydrin synthesis

Quantitative information was obtained on how technological parameters affect the fundamental aspects of the liquid-phase epoxidation of allyl chloride to epichlorohydrin with an aqueous-methanolic solution of hydrogen peroxide in the presence of a titanium-containing zeolite in a batch reactor. The effect of the amount of a solvent, reagents ratio, and temperature was studied. The optimal conditions of epichlorohydrin synthesis were found.     

Synthesis of derivatives of pyrido[3,4-b]- and azepino[3,4-b]pyrrolo[2,3-d]pyrimidines from enamines of α-oxo lactams

The reaction of enamines of some -oxo lactams with 1,3-dimethyl- and 1,3-dibenzyl-4-hydrazinouracils gave the uracilyl-4-hydrazones of these lactams, the catalytic and thermal indolization of which yielded derivatives of pyrido[3,4-b]- and azepino[3,4-b]pyrrolo[2,3-d]pyrimidines. Some reactions of the latter were studied.Communication XXVIII from the series Investigation of Lactams. See [1] for communication XXVII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1398–1403, October, 1977.