Short-wave band in the electronic spectra of sydnones and sydnonimines

A new absorption maximum was observed in the UV spectra of sydnones and sydnonimines at 200 nm, and the effect of substituants and solvents on its position was studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 464–465, April, 1972.     

Comparison of the calculated quantum-chemical characteristics of sydnones and sydnonimines with the experimentally observed molecular parameters

Approximate correlations of the interatomic distances, dipole moments, IR spectral frequencies, and polarographic reduction potentials of sydnones and sydnonimines with the quantum-chemical characteristics of these molecules, calculated by the Hückel method with four variants of parameters obtained from the Pariser-Parr-Pople method, were found.Translated from Khimiya Geterotsiklicheskikh Soedtaenii, No. 10, pp. 1407–1412, October, 1971.     

Study of conjugation in sydnones and sydnonimines by the simple MO LCAO method with Pullman parameters

A number of sydnone and sydnonimine derivatives were calculated by the simple Huckel method with Pullman parameters. Several physical characteristics of the molecules are compared with the calculated data.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1456–1464, November, 1970.     

14N NMR study of some sydnones,sydnonimines and related structures

¹⁴N NMR spectra indicate that the sydnones, their hydrochlorides, the N-acetylsydnonimines, their hydrochlorides and the sydnonimine hydrochlorides studied exist as such in solution. The sydnonimines themselves are involved in a more complicated equilibrium; neutral solutions contain only the corresponding isomeric alkyl-cyanomethyl-nitrosoamine molecules which upon acidification are turned into cyclic cations, representing true sydnonimine structure, protonated at the exocyclic N atom.     

Reductive cyclization of o-cyanocinnamic acids and their analogs

The hydrogenation of esters of o-cyanocinnamic acid or -(o-cyanoaryloxy)carboxylic acids over Raney nickel leads to the corresponding seven-membered lactams. Subsequent reduction of these with lithium aluminum hydride gives 2,3,4,5-tetrahydro[1H]benzo[c]azepine and 1,2,3,5-tetrahydro[4H]benzo[f]-1,4-oxazepine.Communication VI of the series Nitrosophenols and Their Rearrangement Products. See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1288–1292, September, 1971.     

Superacidic cyclization of higher terpenoid acids and their esters

The superacidic cyclization of aliphatic and partially cyclized C₁₅–C₂₅ terpenoid acids and their esters proceeds structure-selectively and stereospecifically, affording -isomers of completely cyclized epimeric ,-unsaturated acids or esters; the configuration of their carboxylic or ester groups is predetermined by the configuration of the double bond conjugated with the carboxyl or ester groups in the starting compounds.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2507–2513, December, 1995.     

1-Acylmethylbenzimidazole-2-sulfonic acids and their cyclization by N-nucleophiles

New preparation method was developed for derivatives of 1,4-dihydro-1,2,4-triazino[4,3-a]-, 2-aryl-1(9)H-, and 1-R-imidazo[1,2-a]benzimidazole underlain by newly synthesized 1-acylmethylbenzimidazole-2-sulfonic acids. The latter react with 2-aminoethanol affording along with the previously described compounds of the 1-(2-hydroxyethyl)imidazobenzimidazole series also compounds of formerly unknown polycyclic system, 2,3,11,12-tetrahydro-1,3-oxazolo[2,3-a]imidazo[1,2-a]benzimidazole.     

Some aminophosphinocarboxylic acids and their derivatives

The addition of Schiff bases of α-aminoacid esters to vinylphosphoryl compounds was studied as a method for the synthesis of phosphinothricin and its analogues. The reaction was found to proceed smoothly in DMSO in the presence of strong nitrogen bases and under the conditions of phase transfer catalysis. The Claisen condensation of β-phosphorylated propionitrile with diethyl oxalate was studied; phosphorylated derivatives of hydroxycitraconic acid nitrile were prepared on hydrolysis; transformation of such a derivative into a cyclic imide as well as into trimethylsilyl esters of these acids and their Z → E transformation were investigated. Cyclization reactions between α,ω-dibromoalkanes and phosphoryl compounds containing an active methylene group affording cyclopropane and other cyclic derivatives were studied. The cyclopropane ring is cleaved by amines to give aminophosphinocarboxylic acids.     

Novel domino cyclization of tryptophan-derived amino nitriles: scope and stereoselectivity

[reaction: see text] The scope and stereoselectivity of the acid-promoted cyclization of new tryptophan-based alpha-amino nitriles derived from either ketones or aldehydes to novel hexahydropyrrolo[1',2',3':1,9a,9]imidazo[1,2-a]indoles is described. This cyclization involves the generation of two or three stereogenic centers. The time and stereoselectivity of this reaction mostly depended on both the steric volume of the substituents at the amino nitrile and its stereochemistry. Unhindered amino nitriles gave exclusively 2-exo-isomers, while hindered amino nitriles, which required higher reaction times, provided also these isomers under kinetic control. Under thermodynamic control, the 2-endo-isomer was the main reaction product, except for the benzaldehyde-derived alpha-amino nitriles, where a favorable electronic interaction between the phenyl and methoxycarbonyl groups in a relative cis-disposition might be responsible of the formation of the 2-exo-isomer as the only cyclization product.     

Synthesis of nitriles of phenylferrocene-carboxylic acids

Conclusions The nitriles of 1-phenylferrocene-2-, -3-, and -1'-carboxylic and p-ferrocenylbenzoic acids have been obtained.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1467–1469, August, 1966.     

Friedel-Crafts alkylation of benzene by normal ω-chloroalkanoic acids and their methyl esters and nitriles

Conclusions In the alkylation of benzene by -chloroalkanoic acids Cl(CH₂)_nCOOH (where n=3–6) and their methyl esters and nitriles, in the presence of A1C1₃, the degree of isomerization of the alkyl chain is less than with the corresponding 1-chloroalkanes, depending on the increase in electron acceptor activity in the sequence HOOC-> CH₃OCO-> CN-.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 367–371, February, 1987.     

Polyampholytes from chloromethylated diphenyl oxide-formaldehyde oligomer,polyamines, and pyridinecarboxylic acids and their nitriles

Conclusions The optimum conditions were found for the synthesis of some new polyampholytes from a chloromethylated diphenyl oxide-formaldehyde oligomer, polyamines, and either pyridinecarboxylic acids or their nitriles, and their properties were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1652–1654, July, 1978.     

Reductive cyclization of delta-hydroxy nitriles: a new synthesis of glycosylamines

[reaction: see text] The stereoselective cyclization of delta-hydroxy nitriles to afford N,O-acetals and the application of this reaction toward the synthesis of glycosylamines is described.     

Some conformational peculiarities of cardenolides and bufadienolides

Summary 1. The capacity of the cardenolides and bufadienolides of the A/B-trans series having an aldehyde group at C₁₀ for giving a semiacetal form is due to the conformational features of ring A, which may be present in a chairboat equilibrium.2. The aldehyde group of strophanthidin does not participate in the formation of an intramolecular hydrogen bond with the hydroxyl group at C₃ and C₅; an intramolecular hydrogen bond occurs between the hydroxyl groups at C₃ and C₅.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 3, pp. 179–184, 1966     

Synthesis of esters of 5-oxo-3-oxapentanecarboxylic acids and their cyclization to give homologs of dioxanone and morpholinone

By hydrogenating methyl esters of 4-furyl-3-oxapropanecarboxylic acids on Pt-C we have obtained the corresponding esters of 5-oxo-3-oxapentanecarboxylic acids and have converted these under the conditions of reductive animation into the corresponding homologs of morpholin-3-one and by reduction in an alkaline medium into homologs of 1,4-dioxan-2-one.