Further heterocyclic analogs of polyaryls

A series of indoles, indolizines, imidazo[1,2-a]pyridines, and quinolines, all of them heterocyclic analogs of polyaryls, have been prepared from diacetyl derivatives of aromatic hydrocarbons.     

Heterylimidazoles IV. Homolytic dissociation of hexaaryldimidazolyls and their heterocyclic analogs

The rate constants and activation energies for homolytic dissociation of 2,2-di[ ()-naphthyl]-, 2,2-diquinolinyl-, and 2,2-di(9-acridinyl)-4,4,5,5-tetraphenyldiimidazolyls in toluene in the presence of,-diphenyl--picrylhydrazine were determined. The degrees of dissociation of the diimidazolyls were found. The effect of substituents on the stability of imidazolyl radicals is discussed.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1536–1539, November, 1974.     

Comparative basicities of heterocyclic analogs of chalcone

Measurements are made of valence vibration frequency shifts of the hydroxyl group of phenol in carbon tetrachloride solution due to the effect of hydrogen bonding with the carbonyl group (u_OH) of chalcone, and its furan, thiophene, selenophene, and N-methylpyrrole analogs. All the compounds form rather stable hydrogen bonds with phenol; u_OH varies in the range 200–284 cm^–1. For propen-3-ones, where the carbonyl group is remote from the heterocyclic ring, a linear relationship is observed between u_OH and pK , previously determined in 100% sulfuric acid solution in glacial acetic acid. The absence of a linear relationship between these quantities for the other ketones is ascribed to steric factors. It is established that heterocyclic groups exhibit a positive conjugation effect as compared with phenol, decreasing in the order N -methyl-2-pyrryl > 2-furyl > 2-selenienyl > 2-thienyl.     

Electronic absorption spectra of heterocyclic analogs of trans-chalcone

Thiophene, furan, and pyrrole analogs of trans-chalcone have UV spectra consisting of bands belonging to the spectra of the corresponding 2-acetylhetaryls and 2-hetarylideneacetones that are shifted bathochromically as a result of mutual perturbation of these two crossconjugated fragments. The absorption curves of 10 chalcones in hexane solution were measured up to 190 nm, the bands of the individual transitions were isolated graphically, and the degree of localization of the electron excitation on the fragments of the molecules was calculated by a new quantum-chemical method.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1202–1205, September, 1977.     

Synthesis and properties of heterocyclic analogs of 4-azidochalcone

A study has been made of the spectral and photochemical properties of a series of heterocyclic analogs of 4-azidochalcone, specifically the pyridine, quinoline, isoquinoline, and quinoxaline derivatives. It has been shown that the absorption spectra of most of the 4-azidocinnamoylarenes are shifted bathochromically in comparison with 4-azidochalcone. The quantum yields of photodissociation of the compounds that were investigated were found to vary within the limits 0.70±0.15. With steric hindrance for the planar conformation of the molecule, a hypsochromic shift of the absorption spectra is observed, along with a slight decrease of the quantum yield.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1340–1343, October, 1991.     

The synthesis of heterocyclic analogs of bisantrene

Bisguanylhydrazones of anthracene-9,10-dicarboxaldehyde have demonstrated excellent antitumor activity. Heterocyclic analogs were synthesized in an effort to expand or modify the activity profile.     

Synthesis and properties of heterocyclic analogs of isoflavones

The condensation of cyanomethyl derivatives of furan and benzofuran with di- and trihydric phenols has given the corresponding 2,4-dihydroxy- and 2,4,6-trihydroxy--heterylacetophenones. The latter have been converted by reaction with acid anhydride, ethoxalyl chloride, and trifluoroacetic anhydride into 3-heterylchromones with methyl, trifluoromethyl, and ethoxycarbonyl groups in position 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1202–1208, September, 1973.     

Complexing of some heterocyclic analogs of diphenylpicrylhydrazine with amines

The complexing of-(6-methyl-2-benzothiazolyl)--phenyl--picrylhydrazine and-(6-methyl-2-benzothiazolyl)--phenyl--(2,6-dinitrophenyl)hydrazine with ammonia and trimethylamine in both the solid state and in solvents (benzene, acetone, hexafluorobenzene, and heptane) was investigated. It was demonstrated that complexing does not depend on the donor and acceptor characteristics of the molecules but is determined by the structural peculiarities of the substance in solution and in the crystalline state.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1200–1201, September, 1972.     

Synthesis of heterocyclic analogs of prostaglandins from pyrrole and indole

Heterocyclic analogs of prostaglandin, dl-2-(trans-3-hydroxyocten-lyl)-N-(6-ethoxycarbonylhexyl)pyrrole and -indole were obtained by the condensation of 2-formylpyrrole and 2-formylindole with 2-oxoheptylidenetriphenylphosphorane, followed by alkylation with ethyl 7-iodoheptanoate and reduction of the keto group by sodium borohydride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 40–43, January, 1986.     

Biologically active heterocyclic analogs of thiourea (review)

The results of research carried out in the Scientific-Research Institute of Medicinals (Budapest, Hungary) are correlated. The structures of 2-aminothiazolines, which can exist in the tautomeric 2-iminothiazolidine form, and of the corresponding analogs of the thiazine series and their acyl derivatives are discussed. A new method for the synthesis of 3-aryl-substituted 2-iminothiazolidines and 2-iminoperhydro-1,3-thiazines is examined. Data on the biological activity of some of the investigated compounds are presented.For example, it is known that 2-(octahydro-1-azocinyl)ethylguanidine (guanethidine) has excellent antihypertensive properties [6–8].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 878–888, July, 1978.     

Study of PMR spectra and structure of heterocyclic analogs of chalcone

A study was made of the PMR spectra of heterocyclic analogs of chalcone containing thiazole, imidazole, benzofuran, and pyridine residues. The shift patterns were determined of the signals under the influence of an aromatic solvent. Through experiments made on the Overhauser homonuclear effect the signals were reliably assigned and the orientation of the heterocyclic fragments in the molecules of chalcones was established.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 244–248, February, 1994. Original article submitted January 19, 1994.     

Hydrogenation of heterocyclic analogs of β-nitrostyrene over palladium catalyst

A study is made of the liquid phase hydrogenation of-(-furyl)-and-(-thienyl)--nitroethylenes over Pd black. It is shown that the nature of the substituent (phenyl, furyl, thienyl) does not affect the mode of addition of the hydrogen to the nitrovinyl group. Conditions are found for catalytic synthesis of high yields of heterylacetaldehyde oximes from nitroalkenes.     

Thiazole analogs of chalcones,capable of functionalization at the heterocyclic nucleus

The synthesis of new amino and alkoxy derivatives of thiazole-5-carbaldehyde, on the basis of which α,β-unsaturated ketones of the thiazole series were synthesized, are described in this paper. The possibility of obtaining chalcones and variation of substitution reactions in the thiazole ring has been shown.     

The Claisen-Schmidt reaction with heterocyclic analogs of o-hydroxyacetphenone

Claisen-Schmidt condensation of 4-hydroxy-3-acetyl-6-methylpyrid-2-one, and its N-methyl and N-phenyl derivatives with aromatic aldehydes is investigated, and it is shown that the products of this reaction are 3-cinnamoyl and not 6-styryl derivatives.     

Mass-spectral study of heterocyclic analogs of 4-dimethylamino- and 4-azidochalcones

The predominant pathway in the mass-spectral fragmentation of 4-dimethylamino- and 4-azidochalcones under the influence of electron impact is cleavage of the aryl-CO and CO-CH bonds and localization of the charge on the fragment with the lower ionization energy. The characteristic chalcone rearrangement with the ejection of a molecule of CO from the molecular ion and subsequent cyclization and aromatization of the stilbene derivative is also observed; in the case of azides this process takes place only after the loss of a molecule of nitrogen by the molecular ion. The differences in the pathways of fragmentation of the hetero analogs make it possible to identify compounds with , , and orientations of the substituent relative to the heteroring nitrogen atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 660–664, May, 1991.     

Synthesis of heterocyclic analogs of isoflavone and homoisoflavone based on 3-formylchromone

The review is focused on recent developments of chemistry of synthetic analogs of natural compounds, isoflavone and homoisoflavone. The possible synthetic strategies to access heterocyclic analogs of these compounds starting from readily available 3-formylchromone and its derivatives (3-cyanochromone, 2-amino-3-formylchromone) and products of its condensation with simplest C- and N-nucleophiles are discussed. The structural features of the reaction products that depend on the nature of the reaction medium, structure of the starting compounds, and reagent ratio are considered. Particular attention is given to the application of the modern strategies of organic synthesis, namely green chemistry approaches, click reactions, domino reactions, etc. Examples of compounds of this group most promising for clinical application due to wide and pronounced pharmacological effects are given.

     

PMR spectra of certain chalcones and their heterocyclic analogs

The PMR spectra of chalcone and some of its derivatives and heterocyclic analogs have been measured, the signals have been assigned to certain atomic groupings and the trans configuration of the molecules has been established. We show that the conductivity of the electronic effects increases from the furan ring to the thiophene and selenophene rings. The effect of a carbonyl group in heteroaromatic systems on the proton signals from a methyl group in the side chain is markedly less than it is on the proton signals from the ring.     

Bioactive heterocyclic analogs of the antitumor drug,podophyllotoxin

3,4-Methylenedioxyphenol (sesamol) condenses with pyrrolidine and aromatic aldehydes to yield Mannich bases of type 4 . The Mannich bases react readily with ketonic reagents to form pyrrolidinylbenzopyran derivatives which provide a simple route to antimitotic and bioactive heterocyclic analogs of the anti-cancer drug, podophyllotoxin.     

Heterocyclic analogs of 5,12-naphthacenequinone. 5. Synthesis of 2,3-diamino-1,4-dimethoxyanthraquinone and its heterocyclic derivatives

A new method for the synthesis of 2,3-diamino-1,4-dimethoxyanthraquinone from quinizarin has been developed. Heterocyclic analogs of 5,12-naphthacenequinone have been synthesized based on this o-diamine-4,11-dimethoxyanthra[2,3-d]imidazole-5,10-dione, 4,11-dimethoxyanthra[2,3-d][1,2,3]triazole-5,10-dione, and 5,12-dimethoxynaphtho[2,3-g]quinoxaline-6,11-dione. On the 70th Birthday of Professor E. Lukevics. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No.1, 96–102, January 2007.