Substituted pyridines. Syntheses based on 2, 5-dimethyl-4-phenyl (β-phenylethyl)pyridine

Condensation of the methyl groups of 2, 5-dimethyl-4-phenylpyridine and 2, 5-dimethyl-4--phenylethylpyridine with some aromatic aldehydes is investigated. The cyclization of 2, 5-dimethyl-4-phenylpyridine to 3-methyl-2-azafluorene and some derivatives of the latter is effected.     

Substituted pyridines. 2, 5-diaroyl-4-phenylpyridines and 2, 5-diamino-4-phenylpyridines

2, 5-Dibenzoyl(di-p-toluoyl, di-p-anisoyl)-4-phenylpyridines, 2, 5-dimethyl-4-acetyl(propionyl)phenylpyridine N-oxides, and 2, 5-diamino-4-phenylpyridine have been obtained.     

Substituted pyridines. 2, 5-Dimethyl-4-p-nitrobenzylpyridine and its reactions

2, 5-Dimethyl-4-p-nitrobenzylpyridine has been prepared. Its nitro group has been reduced and its methylene group oxidized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp 1225–1227, September, 1970.     

Substituted pyridines 5-methyl-4-benzyl-2-styryl(phenylethynyl)pyridines

5-Methyl-4-benzyl-2-styrylpyridine (II), its p-dimethylaminostyryl analog IV, and 5-methyl-4-benzyl-2-(1,3-dioxo-2-hydrindenyl)pyridine (V) have been prepared. II has been converted into 5-methyl-4-benzyl-2-phenylethynylpyridine (VII), 5-methyl-4-benzylpyridine-2-carboxylic acid (VIII), and 3-styryl-6, 7-benzoisoquinoline (X).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1228–1231, September, 1970.     

Oxidation of 4-styryl- 2- phenyl-5, 6-benzoquinoline with potassium permanganate

Oxidation of 4-styryl-2-phenyl-5,6-benzoquinoline with potassium permanganate gave phenyl 2-phenyl-5,6-benzo-4-quinolyl diketone, 2-phenyl-4-formyl-5,6-benzoquinoline, 2-phenyl-5,6-benzocinchoninic acid, and benzoic acid. It is shown that phenyl 2-phenyl-5,6-benzo-4-quinolyl diketone is cleaved under the influence of OH^? ions to the corresponding aldehydes and carboxylic acids; this is explained by the decisive effect of the acidity of the media on the direction of the reaction.     

Substituted pyridines. Dehydrogenation,desamination, and n-desmethylation of 4-amino-1, 2, 5-trimethylpiperidine and (1, 2, 5-trimethyl-4-piperidyl)benzylideneamine

4-Amino-1, 2, 5-trimethylpiperidine and (1, 2, 5-trimethyl-4-piperidyl)benzylideneamine are partially converted into, -lutidine as a result of dehydrogenation, desamination, and N-desalkylation over a type K-12 dehydrogenating catalyst.     

Isomerization of 5, 5-dimethylpyrazolines. preparation and properties of 5, 5-dimethyl-Δ1-pyrazoline and 3, 4-dimethyl-Δ2-pyrazoline

Slow distillation of 5, 5, -dimethyl-²-pyrazoline isomerizes it to 5, 5-dimethyl-¹-pyrazoline, and heating the latter with hydrazine hydrochloride reconverts it to the ² isomer. This is the first experimental evidence that the ² double bond in a pyrazoline can move to the ¹ position, i. e., in a direction the reverse of that previously known. The 5, 5-dimethyl-¹ -pyrazoline described is the simplest ¹ pyrazoline hitherto isolated.The authors heartily thank A. A. Petrov for making it possible to chart the PMR spectra, and V. B. Lebedev and V. S. Stopskom for obtaining and treating the spectrograms.     

Synthesis of 2-(4-cyanophenyl)-5-(4-n-alkyl- and alkoxyphenyl) pyridines

New liquid-crystalline 2-(4-cyanophenyl)-5-(4-alkyl- and alkoxyphenyl)pyridines were obtained by condensation of 1-dimethylamino-3-dimethylimmonia-2-(4-alkyl- or alkoxyphenyl)-1-propene perchlorates with 4-cyanoacetophenone and subsequent conversion of the 1-dimethylamino-2-(p-alkyl- or alkoxyphenyl)-4-(p-cyanobenzoyl)-1,3-butadienes to 5-(4-alkyl- or alkoxyphenyl)-2-(4-cyanophenyl)pyrylium perchlorates and refluxing of the latter with ammonium acetate in acetic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1392–1394, October, 1985.     

Transformations of 2,6-dimethyl- and 2,3-dimethyl-6-ethyl-4-(2′-furyl)pyridines involving the furan and pyridine rings

Alkyl-substituted 4-(2-furyl)pyridines are brominated and nitrated in the C₅' position of the furan ring; however, they do not undergo electrophilic substitution reactions such as acetylation, formylation, and chloro- and aminomethylation. Furyl-substituted indolizines and tetrahydropyridines were obtained from quaternary salts of 2,6-dimethyl-4-(2-furyl)pyridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1665–1667, December, 1982.     

Synthesis of 5-n-alkyl-2-(trans-4-n-alkylcyclohexyl)pyridines

The cyclization of trans-1-acrylyl-4-n-alkylcyclohexanes with trans-1-N-piperidino-1-alkenes was used to synthesize 3-n-alkyl-6-(trans-4-n-alkyl-cyclohexyl)-3,4-dihydro-2-N-piperidino-2H-pyrans, which were converted under the influence of hydroxylamine to 5-n-alkyl-2-(trans-4-n-alkylcyclohexyl)-pyridines. Problems in the stereochemistry of the cyclohexane derivatives in the investigated scheme of synthesis were examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 643–647, May, 1984.     

4－羟基－2，5－二甲基－3（2H）呋喃酮的合成

总结了食品增香剂４－羟基－２．５－二甲基－３（２Ｈ）呋喃国的合成方法，包括近期的合成研究进展，对一些合成方法的优缺点作了评述。参考文献２８篇。     

Selective Synthesis of 2-, 4-, and 5-Cyano Substituted Imidazoles from Imidazole N-Oxides and Trimethylsilyl Cyanide

1-Substituted 2-, 4-, and 5-cyanoimidazoles were produced by reaction of 3-cyclohexyl or 3-p-tolylimidazole 1-oxide and trimethylsilyl cyanide in the presence of triethylamine. The product composition depended on reaction temperature and solvent polarity. By proper choice of these parameters each isomer could be obtained selectively in reasonable yield.     

Synthesis of 1-(β-cyanoethyl)-4-ethynyl-2, 5-dimethyl-4-piperidinols and the corresponding 4-vinyl compounds

Synthesis of 1-(β-cyanoethyl)-4e-ethynyl-2e, 5e-dimethylpiperidin-4a-o1 and the corresponding 4e-vinyl compounds (β-isomers), 1-β-cyanoethyl-4a-ethynyl-2e, 5e-dimethylpiperidin-4c-ol (and the corresponding 4a-vinyl compound) (γ-isomers), and l-(β-cyanoethyl)-2e, 5a-dimethyl-4a-vinylpiperidin-4e-o1 (α-isomer) have been effected.     

Polymesomorphism in a homologous series of 2-(4-alkoxyphenyl)-5-(4-methylphenyl)pyridines

A new series of 2-(4- n -alkoxyphenyl)-5-(4-methylphenyl)pyridines (CH C H C H NC HOC H , n 1-10) (APMPP), which are teraryl compounds containing a pyridine ring in n 2 m 1 the centre position of the rigid core, was synthesized and the phase transitions of the homologues were studied using DSC measurements, polarizing optical microscopy and miscibility tests with terephthalylidene-bis-4- n -pentylaniline (TBPA). Only a nematic phase was found for the shorter alkoxy homologues with n 4. The longer alkoxy homologues with n 4 showed the sequence of enantiotropic phase transitions CrG-SmF-SmC-SmA-N-I, while a monotropic CrH phase was observed for the n 5-10 homologues. Interestingly, the polymesomorphisms appear when n is larger than 4. 3 6 4 5 3 6 4     

2-氯-2-氧代(硫代)-1, 3, 2-二氧磷杂环己烷的甲醇解及其开环 异构化反应

报道了trans-2-氧代-2-氯-4-苯基-5,5-二甲基-1,3,2-二氧磷杂环己烷以及cis-2-硫代-2-氯-4-苯基-5,5-二甲基-1,3,2-二氧磷杂环己烷甲醇解反应的立体化学。结果表明,反应体系的酸碱性对前者甲醇解反应的立体化学有着重要影响。而硫代环磷酰氯在碱性条件下的甲醇解反应存在一个开环异构化过程。     

Benzylation of 2,5-dimethyl-4-phenyl(p-alkylbenzyl) pyridines

New substituted 4-phenyl-2-benzyl- and 2,4-dibenzylpyridines were obtained, and some of their transformations were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 91–94, January, 1972.