Analogs of purine nucleosides and purine mono- and polynucleotides

On the basis of a comparison of the protolysis constants and vibrational frequencies it is shown that intermolecular interactions are present in 6-substituted 9-(,-dihydroxyalkyl)-purines and the corresponding mono- and diphosphates. In addition, in the case of the phosphates the existence of intramolecular interactions of electrostatic character between the phosphate group and the heteroring is also proposed. A comparison of the protolysis constants provides evidence for the different character of the interaction of the dihydroxyalkyl residue with the heteroring of the base in series of adenine and hypoxanthine derivatives.See [1] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1684–1689, December, 1974.     

Comparison of the electronic and steric structures of 1-vinyl-and 1-(prop-1-en-1-yl)pyrroles according to the <Superscript>1</Superscript>H and <Superscript>13</Superscript>C NMR data

According to the ¹H and ¹³C NMR data, 1-isopropenylpyrroles are characterized by larger dihedral angles between the heteroring and exocyclic double bond planes, as compared to isostructural 1-vinylpyrroles, due to steric effect of the α-methyl group in the propenyl fragment. As a result, p-π conjugation with the propenyl group is weaker than with the vinyl group. The propenyl group in 1-isopropenylpyrrole having no other substituents in the heteroring is forced out from the heteroring plane, while the 1-vinylpyrrole molecule is planar. If substituents are present in positions 2 and 5 of the pyrrole ring, the propenyl group on the nitrogen atom becomes orthogonal with respect to the pyrrole ring plane, so that no p-π conjugation is possible. The steric structures of (E)-1-(prop-1-en-1-yl)pyrrole and (Z)-1-(prop-1-en-1-yl)pyrrole are different: the propenyl group in the former is turned relative to the heteroring plane, while the latter molecule is planar.     

Mass spectra of substituted piperidines

The mass spectra of piperidines and N-methylpiperidines with various functional groups attached to the heteroring carbon atoms were studied. The mechanisms of the formation and fragmentation of the amine fragments with various structures and specific hydrogen and skeletal rearrangements are discussed. It is shown that the sequence of cleavage of the heteroring bonds depends on the properties of the substituents and their positions in the ring.Communication 9 in the series Application of mass spectrometry in structural and stereochemical investigations. See [1] for Communication 8.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 65–71, January, 1981.     

Research in the chemistry of pyrazolidine

The rate of hydrogenolysis of 3,5-dioxopyrazolidines at the N-N bond is determined by the number, position, and nature of the substituents in the heteroring. The introduction of a phenyl group into the 1 and 2 positions increases the rate of hydrogenation, while a phenyl group in the 4 position lowers it. On the other hand, an alkyl substituent in the 1 and 2 positions lowers the rate of hydrogenation, while an alkyl substituent in the 4 position increases it. It is assumed that the effect of substituents is a consequence of an increase or decrease in the adsorption of a molecule by the -dicarbonyl or hydrazine fragments; this is in agreement with the results of calculation of the charges on the heteroring atoms. The hydrogenation of 4alkyl-1, 2-diphenyl-3,5-dioxopyrazolidines is limited by their activation, while the hydrogenation of the 4-phenyl derivative is limited by the activation of hydrogen.See [1] for communication XIX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 781–787, June, 1973.     

Bromination of spiropyrans and reduction of their nitro derivatives

Depending on the nature of the nitrogen heteroring, either substitution only in the chromene ring (phenanthridine derivatives) or in both fragments of the molecule (indoline derivatives) occurs in the bromination of spiropyrans of the phenanthridine and indoline series with N-bromosuccinimide in low-polarity solvents, in which they are found in the cyclic form. The activity of the chromene fragment in both types of spiropyrans is approximately the same. The corresponding amino derivatives are formed in the catalytic reduction of spiropyran derivatives with a nitro group in the chromene ring in benzene solution. In alcohol solutions the nitro group and the 3–4 double bond of the chromene ring are hydrogenated simultaneously.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1320–1326, October, 1977.     

Inversion of the nitrogen atom in the aziridine ring. Calculation of 1-ethylideneaminoaziridine by the CNDO/2 method

It is shown that in the ground state of the 1-ethylideneaminoaziridine molecule there is virtually no conjugation of its unshared pair of electrons with the electrons of the N=C bond in the case of a pyramidal structure of the inversion center. A potential surface map was constructed for the conformational transitions due to the possibility of inversion of the nitrogen atom of the heteroring and rotation about the N-N bond. The equivalence of the vicinal protons of the heteroring that is observed in the PMR spectra of the hydrazone derivatives of 1-aminoaziridine is explained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 480–482, April, 1978.     

Isoxazole derivatives in the synthesis of bifunctional compounds by cleavage of the heteroring (review)

The pathways and methods of transformation of isoxazoles to give various acyclic difunctional derivatives (-cyano ketones, -diketones, imino and amino ketones, -amino alcohols, ,-unsaturated ketones, etc.) by opening of the heteroring are examined in the review from the point of view of latent functionality. The prospects for the application of acyclic functional derivatives of isoxazoles and 2-isoxazolines — adducts of 1,3-dipolar cycloaddition of nitrile oxides to olefins and acetylenes — for regio- and stereospecific synthesis are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1155–1173, September, 1981.     

Research on pyrrolo[3,2-f]indolizines

3-(-Oxo--alkoxycarbonylalkyl)- and 3-benzoyl-substituted pyrroles undergo condensation with -unsubstituted pyrroles to give 6H-pyrrolo[3,2-f]indolizines that contain higher acid residues or a phenyl group in the 4 position of the heteroring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 777–780, June, 1977.See [1] for communication IV.     

Synthesis and spectral-luminescence properties of 1-(4′-formylphenyl)-3,5-diaryl-2-pyrazolines

It was demonstrated by means of the IR and PMR spectra that 1-phenyl-3,5-diaryl-2-pyrazolines that contain a grouping with a strong electron-acceptor effect, viz. a 4-nitrophenyl or 4-naphthalanhydride group or a 1,8-naphthoylene-1,2-benzimidazole fragment, in the 3 position undergo Vilsmeier formylation, like unsubstituted 1,3,5-triphenyl-2-pyrazoline, in the para position of the 1-phenyl ring. An investigation of the spectral-luminescence properties of the synthesized 1-(4-formylphenyl)-3,5-diaryl-2-pyrazolines showed that the introduction in the 1-phenyl ring of an electron-acceptor aldehyde group, which is inferior with respect to its acceptor effect to the groupings in the 3 position of the heteroring, does not change the nature of the long-wave absorption band. Substantial hypsochromic and hypsofluoric effects as compared with the corresponding 1-phenyl-unsubstituted compounds are noted in the electronic spectra of these compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 807–811, June, 1982.The authors thank I. D. Kalikhman for recording the PMR spectra.     

Electronic structures and spectral and acid-base properties of pyrrol-, thiophen-, and furananthrones

The IR spectra, electronic absorption and luminescence spectra, solvatochromism, and basicities of compounds of the 6H-dibenz[cd,g]indol-6-one, 6H-anthra[9,1-bc] thiophen-6-one, and 6H-anthra[9,1-bc]furan-6-one groups were studied. The interrelationship between the indicated properties and such structural factors as the 1,10-anthraquinoid structure, the presence of a -surplus heteroring, and the presence of substituents was examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 486–493, April, 1985.     

Reaction of 2,4,6-trimethyl- and 2,4,6-triphenylpyrylium perchlorates with heterocyclic amines

2,4,6-Triphenylpyrylium perchlorate reacts with most heterocyclic amines in dimethylformamide to give quaternary pyridinium salts. 2,4,6-Trimethylpyrylium perchlorate forms similar products only up to a certain limit of the basicity of the amine, below which a proton is transferred from the-methyl group of the pyrylium salt to the pyridine nitrogen atom of the heteroring to give the perchlorate of the starting heterocycle. The residual 2,6-dimethyl--methylenepyran is polymerized to a hexamer.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1461–1467, November, 1974.     

A study of the electron-donating capacity of tin-containing amines by the IR-spectroscopic method

Conclusion The electron-donating capacities of tin-containing amines depend almost exclusively on the donor-acceptor properties and steric effects of the substituents at the N atom. The effect of d-p interaction in the Sn-N fragment of the tin-containing amines, unlike the analogous interaction in their silicon and germanium analogs, is hardly apparent. An increase in the number of trialkylstannyl radicals at the N atom leads to a fall in the donor capacity on passing from mono- to bis(trialkylstannyl)amines and to a considerable rise in this capacity in the tris(trialkylstannyl)amines. The donor properties of the dialkylamino-tannanes fall with an increase in the number of amino groups at the Sn atom.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1294–1298.     

The HPLC Stereoselective Resolution of N-2,4-Dinitrophenylated (DNP) Amine-Containing Enantiomers on Teicoplanin Bonded Phase Using the Methanol-Based Mobile Phase

A variety of compounds containing an amine group (i.e., amino acids and amino alcohols) are fast and much better than baseline enantioresolved on a teicoplanin bonded chiral phase using the methanol-based mobile phase after their pre-column derivatization with 2,4-dinitrofluorobenzene (DNFB) in alkaline medium. The resolution is found relatively insensitive to the structural variations of the analyte and is enhanced as the stereogenic center of analyte is close to the nitro group substituted aromatic moiety of the tagging reagent for stronger - interaction. The resolution is either not observed or unsatisfactory using the acetonitrile-based mobile phase.     

Synthesis and investigation of the electronic spectra of perchlorates of some substituted pyridinium ions

1,2,4,6-Substituted pyridinium perchlorates were obtained, and their electronic absorption and emission spectra were studied. When electron-donor substituents are introduced into the para position of the N-phenyl group, an intramolecular charge-transfer band (l _a transition), with, which the capacity for fluorescence of these compounds in the crystalline state is associated, appears in the long-wave portion of the absorption spectrum. Replacement of the methyl groups in the heteroring by phenyl groups is accompanied by hyperchromic and bathochromic effects and by the appearance of a capacity for fluorescence in solutions at room temperature. These phenomena are explained by an increase in the polarization of the -electron system of the molecules when phenyl groups are introduced.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 359–362, March, 1973.     

Synthesis and photonics of polyfunctional conjugated polyenes

Methods for the synthesis of various types of polyfunctional conjugated polyenes based on aminals of unsaturated -amino aldehydes are surveyed. The influence of the interaction of chromophores on the photophysical properties of polyene bis(amino)-substituted ketones and polymethine salts based on them as well as on the properties of absorption and fluorescence spectra of the cation-anionic polymethine dyes are considered.     

2-Benzopyrylium salts. 27. Formation of substituted chrysenes from 1-methyl-2-benzopyrylium salts

1-Methyl-2-benzopyrylium salts with a free position of the heteroring primarily form substituted chrysenes. In alkaline media this process does not proceed through the intermediate formation of 1,5-diketones.For Communication 26, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1472–1476, November, 1984.     

Synthesis and transformations of 2β,3β-diacetoxy-20-(4,5-dihydroisoxazol-5-yl)-6-oxo steroids

20-Hydroxy-20-(4,5-dihydroisoxazol-5-yl) steroid was brought into reactions typical of functionalization of rings A and B in ecdysteroids. The dihydroisoxazole ring remained unchanged in reactions leading to formation of the 2,3-dihydroxy-6-oxo moiety. The isomerization of 5-bromo derivative in acetic acid in the presence of a catalytic amount of hydrobromic acid and Lewis acids is accompanied by elimination of the hydroxy group from C²⁰ and subsequent migration of the double bond to the heteroring to afford the corresponding isoxazole derivative.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1500–1505.Original Russian Text Copyright © 2004 by Litvinovskaya, Drach, Khripach.     

Research in the chemistry of pyrazolidine XXIII. Study of the reaction of 3,5-dioxopyrazolidines with β-nitrostyrene

Products of Michael condensation containing a 1-phenyl-2-nitroethyl residue in the 4 position of the heteroring are formed in high yields in the reaction of equimolar amounts of 4-methyl-,4-ethyl-, 4-isopropyl-, 4-butyl-, 4-isoamyl-, and 4-phenyl-1, 2-diphenyl-3,5-dioxopyrazolidines and 1,2-diphenyl-3,5-dioxopyrazolidine with -nitrostyrene under basic catalysis conditions. 1,2-Diphenyl-3,5-dioxopyrazolidine adds two equivalents of -nitrostyrene when a twofold excess of the latter is present.See [1] for communication XXII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 963–964, July, 1978.     

Synthesis of 5α-hydroxyecdysteroid analogs containing an isoxazole ring in the side chain

An analog of 5-hydroxyecdysteroids having an isoxazole ring in the side chain was synthesized starting from pregnenolone through intermediate 20-hydroxy-20-(3-isopropyl-4,5-dihydroisoxazol-5-yl) derivative. -Bromination of 6-oxo steroids was accompanied by elimination of the hydroxy group from C²⁰ and migration of the double bond thus formed to the heteroring to afford the corresponding 20-isoxazolyl steroid.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1506–1510.Original Russian Text Copyright © 2004 by Litvinovskaya, Drach, Masalova, Khripach.     

Tautomerism of azine derivatives

The tautomeric properties of 4-pyrimidinylmethanes were studied in the case of 2-CH₃- and 2-CF₃-4-pyrimidinylcyanoacetic esters, 2-CH₃-4-pyrimidinylnitromethane, and 4-pyrimidinylnitromethane. It was shown by ¹H and ¹³C NMR spectroscopy that an equilibrium with the participation of three tautomeric forms — pyrimidine form A and pyrimidinylidene forms B and C with o- and p-quinoid orientations of the double bonds in the heteroring — may be realized in aprotic dipolar solvents (dimethyl sulfoxide).See [1, 2] for communications I and II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1544–1548, November, 1978.