Synthesis and spatial configuration of certain 1-methyl-4-phenyl-4-piperidols

Summary The synthesis of certain 1-methyl-4-phenyl-4-piperidols is described and suggestions are made regarding their possible spatial configuration.The present investigation was carried out under the direction of Academician I. N. Nazarov.     

Synthesis and three-dimensional structures of the cis and trans isomers of 3-methyl-1-tert-butyl-4-acetyl- and 3-methyl-1-tert-butyl-4-carbomethoxy-4-piperidols

The cis and trans isomers of 3-methyl-1-tert-butyl-4-acetyl- and 3-methyl-1-tertbutyl-4-carbomethoxy-4-piperidols, the three-dimensional configurations of which were established by means of their IR and UV spectra, were synthesized in order to study the interrelationship between the structure and reactivity of stereoisomeric piperidines.Translated from Khimiya Geterotsiklicheskikh Soedinenni, No.12, pp. 1659–1665, December, 1973.     

Cyanoethylation of 2,5-dimethyltetrahydro-4-thiopyranone isomers and selective reduction of 2,5-dimethyl-5-(β-cyanoethyl)tetrahydro-4-thiopyranone and — 4-pi pe ridone

It has been found that only the cis isomer (liquid) of 2,5-dimethyltetrahydro-4-thiopyranone is cyanoethylated under the usual conditions. 2,5-Dimethyl-5-(-carboxyethyl)tetrahydro-4-thiopyranone was synthesized by the acid hydrolysis of 2,5-dimethyl-5-(-cyanoethyl)-tetrahydro-4-thiopyranone. The selective reduction with aluminum isopropoxide of 2,5-dimethyl-5-(-eyanoethyl) tetrahydro-4-thiopyranone and of the individual isomers of 2,5-dimethyl-5-(-cyanoethyl)-4-piperidone gave the isomeric 2,5-dimethyl-5-(-cyanoethyl)-tetrahydro-4-thiopyranols and -4-piperidols. The reaction of the isomeric 5-cyanoethyl-4-piperidols with allyl bromide gave the corresponding 1-allyl-2,5-dimethyl-5(-cyanoethyl)-4-piperidols.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 12–14, January, 1972.     

Synthesis of substituted 4-acetylamino-4-phenylpiperidines from the corresponding 4-piperidols under Ritter reaction conditions

The reaction of substituted 4-phenyl-4-piperidols with acetonitrile under Ritter reaction conditions leads to formation of mixtures of the corresponding 4-acetylamino-4-phenylpiperidines and 1,2,5,6-tetrahydropyridines, from which we isolated the target amides by fractional crystallization.M. V. Lomonosov State Academy of Fine Chemical Technology, Moscow 117571. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 776–780, June, 1997.     

Synthesis of 4-hydroxy-1,2,5-trimethyl-4-piperidyl carbinols

Spatial directivity of reactions of the geometrical isomers of 4-acetyl-, 4-propionyl-, and 4-benzoyl-1,2,5-trimethyl-4-piperidols with Grignard reagents and lithium aluminum hydride has been studied. Stereospecific synthesis of some stereoisomeric 4-hydroxy-1,2,5-trimethyl-4-piperidyl carbinols has been effected and their probable spatial configurations have been discussed.     

Synthesis and three-dimensional structures of substituted 4-silyl-4-piperidols

1,2 5-Trimethyl-4-(methyldiphenylsilyl)- and 4-(dimethylphenyl)silyl-4-piperidols were obtained. The isomers of these piperidols of the series, which exist in the chair conformation, have all of their substituents, except the hydroxyl group, equatorially oriented. The isomers of the series exist in solution in the form of an equilibrium mixture of chair and boat conformations, and all of the substituents, except the silyl grouping, are equatorially oriented in the chair conformation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 502–505, April, 1976.     

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 and configuration of diastereomeric 1-(β-dimethylaminoethyl)-2,5-dimethyl-4-plperidols

Diastereomeric 1-(-dimethylaminoethyl)-2,5-dimethyl-4-piperidols were synthesized and their configurations were studied. The spatial orientation of the substituents in the , , and isomers of 2,5-dimethyl-4-piperidol was established, and the stereochemistry of the reduction of 2,5-dimethyl-4-piperidone with sodium in alcohol, with lithium aluminum hydride, and by catalysis on Raney nickel was studied by PMR spectroscopy. A series of transformations at the nitrogen atom of the piperidine ring do not change the configuration of 2,5-dimethyl-4-piperidols, but the stereochemistry of the reduction of the keto group in 2,5-dimethyl-4-piperidones with lithium aluminum hydride depends markedly on the character of the substituent attached to the piperidine nitrogen.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1374–1378, October, 1973.     

First asymmetric synthesis of 4-piperidones. Preparation of optically active diastereomers of 1-α-phenylethyl-2-methyl-4-piperidone

The fundamental possibility of carrying out the asymmetric synthesis of 4-piperidones on the basis of the transamination of 1-substituted 2-methyl-4-piperidone methiodides by optically active -phenylethylamine was demonstrated; the optical yield of the asymmetric transamination is 50%. The occurrence of asymmetric synthesis was confirmed by the isolation of enantiomers of 2-methyl-4-piperidol by reduction of the individual diastereomers of 1--phenyl-ethyl-2-methyl-4-piperidone to the corresponding 4-piperidols with subsequent removal of the chiral substituent attached to the nitrogen atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1378–1382, October, 1985.     

Synthesis and structure of 1-benzoyl-2,5-dimethyl- and 1,2,5-trimethyl-4-arylpiperideins

Isomeric 1-benzoyl-2,5-dimethyl-³-piperidein and 1-benzoyl-2,5-dimethyl-⁴-piperidein were prepared from disubstituted -piperidols and were hydroxylated with osmium tetroxide. The isomeric 1,2,5-trimethyl-4-(p-nitrophenyl)-³- and-⁴-piperideins were obtained from trisubstituted -piperidols.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1200–1206, September, 1986.In conclusion, the authors would like to thank Yu. T. Struchkov and N. I. Lebedev for carrying out the x-ray structural study.     

Asymmetric synthesis of cycloalkano-2,3-piperid-4-ols

A new method for the asymmetric synthesis of cycloalkano-2,3-piperid-4-ols by the reaction of a number of chiral enamino ketones with sodium borohydride is proposed. It is shown that the reduction proceeds via 1,4-hydride addition and leads to the formation of primarily one diastereomeric pair of cycloalkano-2,3-piperidols and their dehydration products. The asymmetric synthesis was confirmed by the production of optically active nitrogen-unsubstituted cycloalkano-2,3-piperid-4-ols when the chiral substituent was removed.Communication 49 from the series Stereochemical Studies. See [1] for Communication 48.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 101–104, January, 1980.     

Synthesis and spectral characteristics of 2-aryl-6-methyl-and 2-aryl-6-benzyl-4,8a-diphenylperhydro[1,3,2]dioxaborinino[5,4-c]pyridines

Aryl-N-methyl-and aryl-N-benzyl-B-substituted 4,8a-diphenylperhydro[1,3,2]dioxaborinino[5,4-c]pyridines, which are representatives of a new class of bicyclic compounds containing four heteroatoms, were synthesized from N-methyl-and N-benzyl-3-(α-hydroxybenzyl)-4-phenyl-γ-piperidols by cyclocondensation with arylboronic acids. The ¹H NMR and mass spectra of these compounds were examined as well as mass spectra of previously obtained analogs. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1253–1259, August, 2008.     

Synthesis of pyridine bases from piperidine derivatives

The corresponding substituted pyridines are obtained in 40–90% yields when N-alkyl-substituted piperidines, gD⁴-piperideines, and secondary and tertiary -piperidols are heated at 240–270C with pyridine N-oxide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 787–789, June, 1977.     

Synthesis and properties of podands with 4-antipyryliminomethine groups

Novel podands with 4-antipyryliminomethine groups on benzenes and various numbers of ethers are prepared. According to UV spectroscopy, these compounds form complexes with alkali, alkaline earth, and transition metals. Extraction of metal picrates demonstrated that the podands selectively form extractable complexes with these salts. A lead-selective electrode with an electrode function 22–24 mV/pPb is based on 1,8-bis[2-(4-antipyryliminomethine)phenoxy]-3,6-dioxaoctane. This enables 1·10^–6–1·10^–2 M Pb to be determined in the pH range 3.5–5.5. The electrode is highly selective for Pb in the presence of alkali and alkaline earth metals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2099–2102, September, 1990.     

Separation of capsular polysaccharide K4 and defructosylated K4 derived disaccharides by high-performance capillary electrophoresis and high-performance liquid chromatography

A rapid, highly sensitive and reproducible high-performance capillary electrophoresis (HPCE) method (electrokinetic chromatography with sodium dodecyl sulfate) is described for the determination of disaccharides present in the polysaccharide from the uropathogenic Escherichia coli K4 bacteria (05:K4:H4) and its defructosylated product. Following chondroitinase digestion of K4 and its derivative, the two disaccharides, DeltaHexAFrc-GalNAc for K4 and deltaHexA-GalNAc for defructosylated K4, are separated and readily determined within 20 min on an uncoated fused-silica capillary using normal polarity at 20 kV and detection at 230 nm. Comparison was made by separation of these two disaccharides in isocratic strong-anion exchange HPLC. A linear relationship was found for the two unsaturated disaccharides over a wide range of concentrations, from approximately 0.5 to 5 micro g for high-performance liquid chromatography (HPLC) and from approximately 0.06 to 0.3 micro g for HPCE. The HPCE separation produced a greater detection sensitivity (about 10 times greater) than HPLC. The described methods were used to evaluate the defructosylation process of K4 under drastic acid conditions. Good correspondence was found for the amount of unsaturated disaccharides for the two techniques.     

MC-SCF and CI calculations on the Si4H4 system

The lowest singlet along with selected high spin states of three isomers of Si₄H₄ have been investigated, using highly correlated wave functions in conjunction with a local pseudopotential approach. Tetrasilabicyclo[1.1.0]but-1(3)-ene 1 and tetrasilatetrahedrane 3a are established as true minima by means of the harmonic vibrational frequencies. The local minimum for tetrasilacyclobutadiene is not a planar 2a but a puckered conformer 2b . Isomer 1 was found to be the most stable of the investigated isomers lying 1.96 eV below 3a and 1.04 eV below 2b . A previously examined bond stretch isomer of tetrasilatetrahedrane 3b lies only 0.2 eV above isomer 1 . The Si? Si bond energies of 2b, 3a , and 3b are determined as 208, 124, and 228 kJ/mol, respectively. An explanation of the bonding situation in 1 is given.     

Determination of 4-ethylguaiacol and 4-ethylphenol in red wines using headspace-solid-phase microextraction-gas chromatography

A method for analysing 4-ethylguaiacol and 4-ethylphenol in the aroma of red wines using headspace-solid-phase microextraction is presented. The fibres used were coated with 100 microm of polydimethylsiloxane. Parameters like ionic strength, agitation of the sample, sample volume, temperature of the sample and adsorption/desorption times were studied and optimised to obtain the best extraction results. The linearity of the response was studied in the usual concentration ranges in wines (4-ethylguaiacol, 40-400 microg/l; 4-ethylphenol, 200-1800 microg/l). Repeatability of the method was determined, and the relative standard deviation was about 10%. Limits of detection and limits of quantification were also determined, and the values found were 1 and 5 microg/l for 4-ethylguaiacol and 2 and 5 microg/l for 4-ethylphenol, respectively. All these values were under the sensory thresholds established for these volatile phenols. The presence of interferences due to the matrix composition implies the use of the standard addition technique for both compounds quantification.     

Separation of capsular polysaccharide K4 and defructosylated K4 by high-performance capillary electrophoresis

A rapid, highly sensitive and reproducible high-performance capillary electrophoresis (HPCE) method (electrokinetic chromatography with sodium dodecyl sulfate) is described for the determination of the polysaccharide from the uropathogenic Escherichia coli K4 bacteria (05:K4:H4) and its defructosylated product. The two polyanions, K4 and defructosylated K4, are separated and readily determined within 30 min on an uncoated fused-silica capillary using normal polarity at 20 kV and detection at 200 nm. A linear relationship was found for the two polysaccharides over a wide range of concentrations, from approximately 30 ng (0.5 microg/microL) to 210 ng (3.5 microg/microL). The described method was used to evaluate the defructosylation process of K4 under drastic acid conditions.     

Liquid crystalline properties and photochromism of 4-alkyl-N-(4-alkloxysalicylidene)anilines

Eight new homologous series of 4-alkyl-N-(4-alkloxysalicylidene)anilines were synthesized. The phase transitions of these homologues were determined using differential scanning calorimetry and polarizing optical microscopy. The homologues began to exhibit liquid crystalline phases as the terminal alkyl or alkoxyl chains were lengthened. In addition, some members of these homologues series exhibited photochromism in the solid state.     

Synthesis,DNA and Photocleavage Studies of Ru(II) Polypyridyl Complexes: [Ru(dppz)(pyz)4](ClO4)2 and [Ru(dppz)(dmpyz)4](ClO4)2 Complexes

In view of the growing interest for the synthesis of metal complexes and their interaction with DNA, we have synthesized and characterized two complexes containing ruthenium as metal center. The complexes are of the type [Ru(dppz)L₄](ClO₄)₂ where L are biologically important ligands such as pyrazole and dimethylpyrazole. The characterization of these complexes is done by ¹H NMR, ¹³C NMR, elemental analysis and mass spectroscopy. The interaction of these complexes with CT DNA was monitored and binding constants were determined using absorption and fluorescence spectroscopy. The mode of binding was found to be intercalative for both complexes and was determined using hydrodynamic viscosity studies. The complexes were further studied for photocleavage studies with supercoiled plasmid pBR322 DNA.