Synthesis and properties of amides of 2-substituted 3-aryl- and 3-pyridylaminoacrylic acids

The reaction of aryl- or pyridylamines with ethyl orthoformate and malonanilic acid gave amides of 2-(N-arylcarbamoyl)-, 2-cyano-, 2-ethoxycarbonyl-3-arylaminoacrylic acids and their corresponding 3-pyridyl analogs. IR and PMR spectroscopy indicates that these compounds exist in the enamine form with strong intramolecular hydrogen bonds. Amides of 3-(2-pyridylamino)-2-ethoxycarbonylacrylic acid cyclize to give amides of pyrido[1,2-a]pyrimidine-3-carboxylic acid, which react with hydrazine hydrate to give amides of 3-aminopyrazole-4-carboxylic acid.Perm Pharmaceutical Institute, 614000 Perm. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 629–633, May, 1994. Original article submitted February 8, 1994.     

Research on naphthyridines. 10. Synthesis and ionization constants of 10-alkylaminobenzo[b]-1,8-naphthyridines

10-Alkylaminobenzo[b]-1,8-naphthyridines were synthesized by cyclization of 2-arylaminonicotinic acid alkylamides by means of phosphorus oxychloride. The pK_al values of the 10-alkylaminobenzo[b]-1,8-naphthyridines, which range from 8.74 to 8.50, were determined by potentiometric titration in anhydrous ethanol.See [1] for communication 9.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 799–801, June, 1979.     

Synthesis and acid-base transformations of 8-substituted 10-phenyl-10-hydroxy-10H- pyrido [2,3-b ]chromenes

The corresponding 2-(p-substituted phenoxy)-3-aroylpyridines were obtained by the reaction of 2-(p-substituted phenoxy)nicotinonitriles with phenylmagnesium bromide. It is shown that they are readily cyclized to 8-substituted 10-phenyl-10-hydroxy-10H-pyrido[2,3-b]chromenes by the action of concentrated sulfuric acid in glacial acetic acid. The pK_R+ values of the cyclization products, which range from–7.70 to –10.83 and correlate with the _p ⁰ substituent constants, were determined by spectrophotometry.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 614–616, May, 1982.     

Reactions of 6-methyl- and 4,6-dimethyl-2-arylaminonicotinonitriles with acids

A substituted nicotininc acid is formed when 6-methyl-2-anilinonicotinonitrile is refluxed with concentrated hydrochloric acid, whereas 4,6-dimethyl-2-anilinonicotinonitrile is not hydrolyzed under these and more severe conditions because of steric hindrance. Both of these nitriles undergo cyclization to 10-aminobenzo-[b]-l,8-naphthyridine derivatives under the influence of concentrated sulfuric acid. When 6-methyl-2-arylaminonicotinonitriles are heated in polyphosphoric acid (PPA), they are converted to 2-arylaminonicotinic acid amides and, in part, to benzo[b]-l,8-naphthyrid-10-one derivatives, while 4,6-dimethyl-2-arylaminonicotinonitriles are converted primarily to 10-aminobenzo[b]-l,8-naphthyridines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 674–678, May, 1982.     

Synthesis of acid-base transformations of 3-aroyl-6-methyl-2-oxopyridines

In hydrolysis of 3-aroyl-6-methyl-2-methoxypyridines, 3-aroyl-6-methyl-2-oxopyridines are formed, which with methyl iodide in an alkaline medium give the corresponding 1-methyl derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1354–1356, October, 1986.     

Quasi-tautomerism of 5-hydroxy-5-phenyl-5H-pyrido[2,3-b]chromenes in sulfuric acid

The existence of a quasi-tautomeric equilibrium in solutions of 5-hydroxy-5-phenyl-5H-pyrido[2,3-b]chromenes in sulfuric acid, which was confirmed by a linear dependence of the logarithms of the indicator ratios on acidity function H_R — H_O with a slope close to unity, was established. The pK values of this equilibrium correlate with the _p ^o and _R. ^o substituent constants.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 753–755, June, 1984.     

Investigation of naphthyridines

2-Acetyl-10-aryl-1,2,3,4-tetrahydrobenzo[b]-1,6-naphthyridines were obtained by reaction of 4-(2)-R-2-aminobenzophenones with 1-acetyl-4-piperidone, and their pK_a values were determined. It was found that they are oxidized by hydrogen peroxide to give the corresponding N-oxides in good yields. The N-oxides are converted to the 4-acetoxy derivatives by the action of acetic anhydride.See [1] for communication VII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1383–1385, October, 1976.     

Sorption properties of cellulose filters with covalently immobilized thiosemicarbazide

A novel thin-layer cellulose adsorbent bearing chemically immobilized thiosemicarbaside is synthesized. The adsorbent is used for the preconcentration of cobalt(II), mercury(II), and cadmium(II) followed by their X-ray fluorescence quantification in the concentrate. The physicochemical parameters of metal sorption are determined.     

Synthesis and properties of (4-carbamoyl-quinol-2-yl) cyanoacetic acids

Reaction of 2-chlorocinchoninic acid anodes with malonodinitrile or cyanoacetic ester and potassium carbonate in refluxing DMF gives (4carbamylquinol-2-yl)malonodinitriles and -cyanoacetic esters respectively. Using UV and PMR spectroscopy it was shown that they exist in the ylidene form, being stabilized in the latter case by a chelate type intramolecular hydrogen bond.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 519–522, April, 1996.     

A parallel block overlap preconditioning with inexact submatrix inversion for linear elasticity problems

We present a parallel preconditioned iterative solver for large sparse symmetric positive definite linear systems. The preconditioner is constructed as a proper combination of advanced preconditioning strategies. It can be formally seen as being of domain decomposition type with algebraically constructed overlap. Similar to the classical domain decomposition technique, inexact subdomain solvers are used, based on incomplete Cholesky factorization. The proper preconditioner is shown to be near optimal in minimizing the so‐called K‐condition number of the preconditioned matrix. The efficiency of both serial and parallel versions of the solution method is illustrated on a set of benchmark problems in linear elasticity. Copyright © 2002 John Wiley & Sons, Ltd.