Basicity of 2-phenyl-5-R-1,3,4-oxadiazoles

We have studied the basicity of 2-phenyl-5-R-1,3,4-oxadiazoles (R = H, Me, CH₂Ph, t-Bu, CH₂Cl, CCl₃, CF₃) in aqueous sulfuric acid solutions. These compounds are weak organic bases (pK_BH ⁺ is −1.8 to −5.2). The values of pK_BH ⁺ determined on the H₀ and X acidity function scales agree well with each other. The substituent at the 5 position has a substantial effect on the basicity of the 1,3,4-oxadiazole ring. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 748–756, May, 2006.     

Arylmethylene derivatives of 5-R-3H-furan-2-ones and N-aryl-5-R-3H-pyrrol-2-ones in reaction with acetylacetone

Reaction with acetylacetone in the series of 3-arylmethylene-substituted furan-2-ones and pyrrol-2-ones was studied. 8-R-4-Acyl-5-aryl-3-oxo-9-oxabicyclo[4.3.0]nona-1,7-dienes and N-tolyl-8-R-4-acyl-5-aryl-3-oxo-9-azabicyclo[4.3.0]nona-1,7-dienes were synthesized. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1457–1462, October, 2007.     

Synthesis of 4-Arylhydrazono-3-arylthiomethyl-4,5-dihydro-1H-1-R-5-pyrazolones

It has been established that interacting ethyl 2-arylhydrazono-4-arylthio-3-oxobutyrates with hydrazine, methylhydrazine, and phenylhydrazine forms 4-arylhydrazono-3-arylthiomethyl-4,5-dihydro-1H-1-R-pyrazolones.     

Reactions of 3-R-5-nitropyridines with nucleophiles: Nucleophilic substitution vs conjugate addition

A number of 3-R-5-nitropyridines were synthesized and their reactions with various types of nucleophiles were investigated. The reaction outcome depends on the nature of a nucleophile: in case of anionic O-, N- and S-nucleophiles the previously unreported substitution of non-activated nitro group occurred while carbon nucleophiles underwent dearomatization of the pyridine ring with the formation of products of 1,2- and 1,4-addition.     

Cyclocondensation of N-aryl-3-oxobutanethioamides with 5-amino-3-R-4-R1-pyrazoles

The cyclocondensation products of N-aryl-3-oxobutanethioamides with 5-amino-3-R-4-R¹-pyrazoles are 4-(arylamino)-2-methyl-7-R-8-R¹-pyrazolo[1,5-a]pyrimidine and pyrazolo[1,5-a]pyrimidine-4-thione derivatives, the ratio of which depends on the nucleophilicity of the starting 5-amino-3-R-4-R¹-pyrazoles and the presence of a proton donor solvent. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1550-1555, October, 2008.     

Complexes of Erbium and Lutetium of Different Compositions with 4-R-5-Nitro-substituted Phthalocyanines

Metal complexes (metal: ligand = 1 : 1) have been obtained via the reaction of 4-R-5-nitrophthalonitriles with erbium and lutetium acetates and chlorides. 1 : 2 heteroleptic complexes have been synthesized based on them, containing unsubstituted and octasubstituted phthalocyanine ligands at the metal atom. The products have been characterized by a set of physico-chemical methods.     

Convenient synthesis of 1-norbornyl-5-R-1H-1,2,3-triazole-4-carboxylic acids

Russian Journal of Organic Chemistry - A convenient procedure was developed for the synthesis of 2-azidobicyclo[2.2.1]heptane whose click reaction with phenylacetylene afforded...     

Synthesis and Properties of 6-Amino-7-hetaryl-5-R-5H-pyrrolo[2,3-b]pyrazine-2,3-dicarbonitriles

We have established that when 5-chloro-6-[cyano(2,3-dihydro-1-R-benzo[d]azol-2-yl)methyl]-2,3-pyrazinedicarbonitriles are reacted with nucleophilic reagents (aliphatic and aromatic amines, hydrogen sulfide), annelation of the five-membered ring occurs on the [b] face of the pyrazine with formation of 6-amino-7-hetaryl-5-R-5H-pyrrolo[2,3-b]pyrazine-2,3-dicarbonitriles and 6-amino-7-(1H-benzo[d]imidazol-2-yl)thieno[2,3-b]pyrazine-2,3-dicarbonitrile respectively. Further heating with excess of acylating reagent leads to formation of a novel heterocyclic system 1H-benzo[4,5]imidazo[1,2-c]pyrazino[2',3':4,5]pyrrolo[3,2-e]pyrimidine. Reaction of vicinal dinitriles with hydrazine hydrate leads to the novel system 1H-pyrrolo[2',3':5,6]pyrazino[2,3-d]pyridazine.     

9-R-10-Telluroniaanthracene perchlorates

10-Telluroniaanthracene perchlorates with various substituents in the 9 position were obtained by the action of 70% HClO₄, on 9-R-10-tellura-9-anthracenols and of trityl perchlorate on 9-R-10-tellura-9-anthracenols and 9-R-9H-10-telluraanthracenes. The IR, UV, and PMR spectral characteristics of the products' were investigated.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 343–346, March, 1981.     

Synthesis of 5-R-3-Diphenylmethylene-2,3-dihydro-2-furanones from 5-Substituted 2,3-Dihydro-2,3-furandiones and Phenylbenzoyldiazomethane

3-Reactions of 5-aryl, 5-heteryl, and 5-styryl-2,3-dihydro-2,3-furandiones with phenylbenzoyldiazomethane gave rise to 5-substituted 3-dipenylmethylene-2,3-dihydro2-furanones. The possible intermediates and reaction products were investigated by semiempirical SCF MO LCAO method in AM1 approximation.     

Electronic structures and electrophilic substitution in 2-(4-R-2-quinolyl)thiophenes and 5-(4-R-2-quinolyl)-2,2′-dithienyls

The electronic structures and reactivity indexes (RI) of 2-(4-R-2-quinolyl)thiophenes and 5-(4-R-2-quinolyl)-2,2-dithienyls (R = H, COOH, COOC₂H₅, and NHCOCH₃) and their protonated forms were calculated by the Pariser-Parr-Pople (PPP) method. The peculiarities of the geometrical and -electron structures were established. The calculated reactivity indexes are compared with experimental data on the electrophilic substitution reactions of the investigated compounds. A qualitative agreement between the calculated values and the experimental data was established. It is shown that quinoline derivatives of thiophene are less reactive than the corresponding dithienyl compounds in electrophilic substitution reactions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 751–754, June, 1979.     

Reactivity of the A-CH=N-NR-CX-B system. 4-R-5-hydroxy-5-phenyl-2,3,4,5-letrahydro-1,2,4-triazine-3-thiones

The behaviour of phenylglyoxal thiosemicarbazones towards aqueous sodium hydroxide have been studied. Examples of addition compounds, 5-hydroxy-5-phenyl-2,3,4,5-tetrahydro-1,2,4-triazine-3-thiones, are reported.     

Synthesis and reactions of 1-R-3-benzoyl-5-ethoxycarbonyl-6-oxo-1,2,3,6-tetrahydropyridine-2-thiones

Cycloacylation of N-R-3-oxo-3-phenylpropanethioamides by diethyl ethoxymethylenemalonate occurs selectively to form 1-R-3-benzoyl-5-ethoxycarbonyl-6-oxo-1,2,3,6-tetrahydropyridine-2-thiones which are convenient starting materials for the synthesis of bi-and tricyclic hetero systems including the previously unknown 9-R-7-ethoxycarbonyl-5-phenyl-8,9-dihydropyrido[2,3-d][1,2,4]triazolo[1,5-a]-pyrimidin-8-ones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1660–1669, November, 2007.     

Chichibabin-type condensation of cyclic ketones with 3-R-1,2,4-triazin-5(4H)-ones

Reactions between substituted 1,2,4-triazines and ketones were investigated. General procedures for one-pot synthesis of hydrogenated derivatives of such polycyclic systems as benzo[c][1,2,4]triazino[1,6-a][2]azecine, [1,2,4]triazino[1,6-f]phenantridine, and dicyclopenta[b,d]pyrido[1,2-f][1,2,4]triazine are described.