1,2,5-Trimethyl-4-allyl(propargyl)-4-aryl(hetaryl)aminopiperidines

Individual geometrical isomers of some 1,2,5-trimethyl-4-allyl-4-aryl(hetaryl)aminopiperidines were isolated, and their structures were established. 1,2,5-Trimethyl-4-propargyl-4-aryl(aralkyl)aminopiperidines were obtained from 1,2,5-trimethyl-4-aryliminopiperidines and propargylmagnesium bromide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 942–946, July, 1991.     

Synthesis and three-dimensional structures of geometrical isomers of some 4-substitute d 1,2,5-trimethyl-4-acetoxy- and 1,2,5-trimethyl-4-benzoxypiperidines

Stereoisomers of the corresponding 4-substituted 1,2,5-trimethyl-4-acetoxy- and 1,2,5-trimethyl-4-benzoxypiperidines were obtained by acylation of the geometrical isomers of 1,2, 5-trimethyl-4-piperidol and its 4-ethynyl, 4-ethyl, and 4-phenyl-substituted derivatives. The preferred conformations of the investigated esters were elucidated by means of the PMR and IR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No.1, pp. 50–55, January, 1973.     

Diastereoisomeric 1,2,5-trimethyl-4-mtolylpiperidin-4-ols and 2,5-dimethyl-4-m-tolylpyridine

The preparation of 1,2,5-trimethyl-4-m-tolypiperidin-4-ol and the isolation of three of its diastereoisomers are described. The passage from this piperidinol to 2,5-dimethyl-4-m-tolylpyridine has been effected. Some derivatives of the latter compound have been obtained.Translated from Khimiya Geterotsiklicheskikh Soedinii, Vol. 6, No. 6, pp. 782–786, June, 1970.     

Asymmetric synthesis,stereochemistry, and absolute configuration of 1,2-5-trimethyl-5-(2-cyanoethyl)- and 1,2,5-trimethyl-4-piperidinones

The asymmetric Michael alkylation of (–)-1,2,5-trimethyl-4-(1S-phenylethylimino)piperidine by electrondeficient alkenes proceeds with the formation of(+)-cis-(2S,5S)- and (–)-trans-(2R,5S) diastereomers of 1,2,5-trimethyl-5-(2-cyanoethyl)- and 1,2,5-trimethyl-5-(2-methoxycarbonylethyl)-4-piperidinones containing a chiral quaternary center C(₅). The spatial structure of these new chiral 4-piperidinones has been established on the basis of ¹H and ¹³C NMR spectroscopic data. The absolute configuration of the C(₂) and c(₅) chiral centers in the diastereomers has been determined by stereochemical correlation on the basis of circular dichroism data.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1369–1378, October, 1992.     

1,2,5-Trimethyl-4-aminopiperidine and 3, 6-dimethyl-4-phenyl-2-aminopyridine

1,2,5-Trimethylpiperid-4-one is used to prepare 1, 2, 5-trimethyl-4-aminopiperidine, which is then converted to 1, 2, 5-trimethyl-4-(diethylaminoacetylamino)piperidine. Amination of 2, 5-dimethyl-4-phenylpyridine is effected, and 3, 6-dimethyl-4-phenyl-2-aminopyridine is thereby obtained.     

Synthesis of 2,5-dimethyl- and 1,2,5-trimethyl-4-dimethoxyphosphinylpiperid-4-ols

Dimethyl phosphite is condensed with 2,5-dimethyl- and 1,2,5-trimethylpiperid-4-ones in the presence of alkali metal alkoxides. It is shown that 2,5-dimethyl- and 1,2,5-trimethyl-4-dimethoxyphosphinyl-piperid-4-ols are formed in both cases in the same stereoisomeric forms and in high yields. Methylation of the piperidol isomer which was not substituted at the nitrogen atom indicated that the two piperidols formed had the same configuration.     

Condensation of 1,2,5-trimethyl-4-piperidone with ethyl- and naphthylacetylenes and synthesis of substituted pyridines

The Favorskii reaction with 1,2,5-trimethyl-4-piperidone and ethyl- and naphthylacetylenes gave the corresponding piperidols, the hydrogenation of which gave 1,2,5-trimethyl-4-nbutyl(or 2-naphthylethyl)-4-piperidols. 4-Phenyl- and 4-butyl-2,5-dimethylpyridine were condensed with formaldehyde, and some of the transformations of the resulting-hydroxyethyl derivatives were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 349–352, March, 1973.     

Synthesis of 1,2,5-trimethyl-4-ethoxycarbonylmethyl-4-hydroxypiperidine and its homologs

1,2,5-Trimethyl-4-ethoxycarbonylmethyl-4-hydroxypiperidine was obtained by the Reformatsky reaction between 1,2,5-trimethyl-4-piperidone and ethyl bromoacetate. Homologs were obtained from the same piperidone and ethyl -bromo--alkylacetates. Some further reactions of these hydroxypiperidines were studied.     

1,2,5-Trimethyl-4-(p-hydroxyaryl)-δ3-tetrahydropyridines and their spatial structure

The condensation of 1,2,5-trimethylpiperidine-4-one with phenol and isomeric cresols yields 1,2,5-trimethyl-4-(p-hydroxyphenyl)- and (p-hydroxytolyl)-³-tetrahydropyridines, the structure and conformation of which have been studied by proton NMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1367–1370, October, 1986.     

Cyanoethylation of some n-substituted 2,5-dimethyl-4-piperidones

1,2,5-Trimetnyl- and 1-(-chlorocrotyl)-2,5-dimethyl-5-(-cyanoethyl)-4-piperidones were synthesized and separated into individual isomers. The corresponding isomeric 5-(-carboxyethyl)-4-piperidones were obtained by hydrolysis. The isomeric 1,2,5-trimethyl-3,5-bis(-cyanoethyl)- and 1,2,5-trimethyl-3,3,5-tris(-cyanoethyl)-4-piperidones were synthesized by subsequent cyanoethylation of the individual 1,2,5-trimethyl-5-(-cyanoethyl)-4-piperidone isomers.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 479–481, April, 1971.     

Synthesis and three-dimensional structure of the benzoates and p-nitrobenzoates of the geometrical isomers of substituted 4-hydroxypiperidines

The corresponding stereoisomeric p-nitrobenzoates were obtained by reaction of the geometrical isomers of 1,3-dimethyl-, 1,2,5-trimethyl-, and 1-tert-butyl-3-methyl-4-hydroxypiperidines with p-nitrobenzoyl chloride. The stereoisomers of the corresponding benzoates were also synthesized from the geometrical isomers of 1,3-dimethyl-4-hydroxypiperidines. The primary conformations of the investigated compounds in solution were established by means of their PMR spectra.     

N-substituted 2, 5-dimethyl-4-ethynyl(vinyl)piperid-4-ols

They -isomers of 1-(3-chlorobuten-2-yl)- and 1-benzyl-2,5-dimethyl-4-ethynylpiperid-4-ols (I, II) and of 1-(3-chlorobuten-2-yl)-2,5-diemethyl-4-vinylpiperid-4-ol (III) and the quaternary salts of compounds I–III and of the -isomers of the 1,2,5-trimethyl-4-ethynyl-(vinyl)piperid-4-ols [1] have been synthesized.     

Synthesis and nitration of NH- and N-vinyl-4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridines

It has been shown that the most efficient catalysts for the synthesis of 4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridine from 1,2,5-trimethylpyridin-4-one and acetylene under Trofimov conditions are rubidium and potassium hydroxides. Use of Triton B or a mixture of trimethylbenzylammonium chloride with rubidium hydroxide as catalyst gives O-alkylated oxime. Their configurations and conformations were established through separation of the individual isomers of 1-vinyl-4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridines. Acetyl nitrate nitration of the cis isomer of this compound gave the 2- and 3-nitro derivatives. Similar nitration of 4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridine gave the 2-nitro-7-hydroxy derivative.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1375–1380, October, 1991.     

Asymmetric synthesis and absolute configuration of 1-α-phenylethyl-2,5-dimethyl-4-piperidone isomers

Reaction of the methyl iodide of trans-1,2,5-trimethyl-4-piperidone with S--phenylethylamine proceeds asymmetrically and leads in 66% optical yield to the formation of the cis- and trans-diastereomeric pair of 1-(-phenylethyl)-2,5-dimethyl-4-piperidone, in which the new asymmetric centers possess the 2S,5S- and 2S,5R-configurations, respectively. According to x-ray structural analysis, the minor trans-1-(-phenylethyl)-2,5-dimethyl-4-piperidone component possesses the 2R,5S-configuration. The occurrence of asymmetric synthesis accompanying transamination was confirmed via the preparation of enantiomers of trans-2,5- and trans-1,2,5-trimethyl-4-piperidones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1641–1648, December, 1986.     

(1,2,5-Trimethyl-4-piperidylidene)-α-naphthylamines in the synthesis of 9-methylnaphtho [1, 2-b ] [1, 6 ]naphthyridine and 2,3-dimethyl-4- azaphenanthrene

9-Methylnaphtho[1,2-b][1,6]naphthyridine and 2,3-dimethyl-4-azaphenanthrene were obtained by the catalytic dehydrocyclization of (1,2,5-trimethyl-4-piperidylidene)--naphthylamine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 378–382, March, 1972.     

7,8,9-trimethyl-1-phenyl-3<Emphasis Type="Italic">H</Emphasis>-pyrrolo[2,1-<Emphasis Type="Italic">d</Emphasis>][1,2,5]triazepin-4(5<Emphasis Type="Italic">H</Emphasis>)-one. Synthesis and reactions

A strategy was developed for the synthesis of 7,8,9-trimethyl-1-phenyl-3H-pyrrolo[2,1-d][1,2,5]-triazepin-4(5H)-one, reactions of its functionalization at the С⁴ atom and aza rings fusion at the С⁴?N³ bond were explored. The formation mechanism of the pyrrolo-1,2,5-triazepinone scaffold was suggested.     

1,4-bis(4′-hydroxy-1′,2′,5′-trimethyl-4-piperidyl)-1,3-butadiyne and its derivatives

1.4-Bis(4-hydroxy-1,2,5-trimethyl-4-piperidyl)-1.3-butadiyne has been synthesized from the individual isomers of 4-ethynyl-1,2,5-trimethyl-4-piperidol. Hydrogenation, bromination, and cleavage have given, respectively, 1,4-bis(4-hydroxy-1,2,5-trimethyl-4-piperidyl)butane, 1,4-bis(4-nydroxy-1,2,5-trimethyl-4-piperidyl)-1,2,3,4-tetrabromo-1, 3-butadiene, and 4-(1,3-butadiynyl)-1,2,5-trimethyl-4-piperidol.     

PMR studies of N-substituted-2,5-dimethyl-4-piperidones

PMR characteristics of some isomeric 1-substituted-2,5-dimethyl-4-piperidones are reported and major isomers shown to have a trans 2,5-dimethyl configuration. Differences between benzylic methylene signals of isomeric 1-benzyl analogs provide evidence of the preferred conformation of the cis derivative. Evidence of the D/H exchange of α-protons in 1,2,5-trimethyl-4-piperidone base and of addition of D₂O to the carbonyl group of the corresponding hydrochloride and methiodide salts is also demonstrated. The effect of a 2-methyl substituent upon the chemical shifts of N-methyl groups in some piperidine methiodides is discussed.     

1H and 13C NMR spectra and three-dimensional structures of 1,2,5-trimethyl-4-phenylaminopiperidine isomers

The three-dimensional structures of two isomers of 1,2,5-trimethyl-4-phenylaminopiperidine were established on the basis of an analysis of their ¹H and ¹³C NMR spectra. The piperidine ring has a chair conformation in both isomers. The isomer has the 1,2e,5a, trimethyl-4e-phenylaminopiperidine structure, while the isomer has the 1,2e,5e-trimethyl-4e-phenylaminopiperidine structure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1512–1515, November, 1982.     

Properties of 4H-[1]benzopyrano[3,4-c]-[1,2,5]-selenodiazol-4-one

4H-[1]benzopyrano[3,4-c][1,2,5]selenodiazol-4-one has been synthesized by the reaction of 3,4-diaminocoumarin with selenous acid and its reaction with several nucleophiles (alkali, ammonia, amines, hydrazine hydrate) and its nitration have been studied. Using PMR spectroscopy, a comparative kinetic study of the opening of the lactone ring in 6,8-dinitro-4H-[1]benzopyrano[3,4-c][1,2,5]seleno- and thiadiazol-4-ones has been carried out.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 128–133, January, 1991.