Prototropic isomerization of trans-4-benzamido-3-hydroxy-2-(4-carbomethoxybutylidene)thiophan to cis- and trans-4-benza mido-3-oxo-2-(4-carbomethoxybutyl) thiophan

trans-4-Benzamido-3-hydroxy-2-(4-carbomethoxybutylidene)thiophan (I) was prototropically isomerized in the presence of hydrogen chloride. It is shown that the two possible isomers cis- and trans-4-benzamido-3-oxo-2-(4-carbomethoxybutyl)thiophan — are formed in the process.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No, 2, pp. 175–177, February, 1973.     

Diene condensation of cis- and trans-2-cyclododecenone

Conclusions In the diene condensation of the cis- and trans-2-cyclododecenones with butadiene only the transisomer reacts, with the formation of trans-bicyclo [10. 4. 0]-14(15)-hexadecen-2-one, which when treated with t-C₄H₃OK is isomerized completely to cis-bicyclo[10. 4. 0]-14(15)-hexadecen-2-one.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2157–2159, September, 1973.     

Synthesis of 2-alkylthio-5-acetyl-2-oxazolines

The reaction of 2-acetyloxiranes with alkyl thiocyanates in the presence of Lewis acids (BF₃, AlCl₃) has given 2-alkylthio-5-acetyl-2-oxazolines (yields 40–60%). It has been shown that the reaction of trans-2-acetyl-3-methyloxirane and of trans-2-acetyl-3-methyloxirane and of trans-2-acetyl-2,3-dimethyloxirane with alkyl thiocyanates takes place stereospecifically and leads to cis-2-alkylthio-5-acetyl-2-oxazolines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 468–471, April, 1980.     

Synthesis of the sex pheromone of the grain moth Ephestia elutella

A most convenient synthesis of tetradeca-9Z,12E-dien-l-ol and its acetate — components of the sex pheromone of the grain moth — has been carried out on the basis of a scheme for obtaining a cis-1,trans-4-dienic system.A. S. Sadykov Institute of Bioorganic Chemistry, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, Vol. 6, pp. 834–840, November–December, 1989.     

cis — trans isomerism in the octahydrobenzofuran series

The transformations of cis-2-methyl- and 2,2-dimethyloctahydrobenzofurans on acid catalysts — Al₂O₃ and ZnCl₂/Al₂O₃ — were studied. cis-2-Methyloctahydrobenzofuran undergoes cis-trans isomerization and is dehydrogenated to 2-methyl-2,3,4,5,6,8-hexahydrobenzofuran.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 147–148, February, 1973.     

Reaction of 2,4-disubstituted 1,3-dioxolanes with dihalocarbenes

The insertion of dihalocarbenes into the C₍₂₎-H bond of cis- and trans-2-alkyl-4-propyl-1,3-dioxolanes leads to mixtures of stereoisomers.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1030–1031, August, 1991.     

Formation of hexenes from 1-pentanol in the presence of cupric chloride

Conclusions The dehydration of 1-pentanol in the presence of CuCl₂ at 140–200 and a pressure of 5–80 atm, in either a CO or a N₂ atmosphere, is accompanied by the formation, along with pentenes, of large amounts of hexenes (mainly cis- and trans-2-hexene).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1886–1887, August, 1973.     

Oxy acids of the seed oil of the cotton plant of variety Tashkent-1

Summary Seven oxy acids have been isolated from cottonseed oil of variety Tashkent-1 for the first time and their structures have been shown: cis-12,13-epoxyoctadec-cis-9-enoic, cis-9,10-epoxyoctadec-cis-12-enoic, cis-9,10-epoxyoctadecanoic, 9,10:12,13-diepoxyoctadecanoic, 9-hydroxyoctadeca-trans,cis-10,12-dienoic, 13-hydroxyoctadeca-cis,trans-9,11-dienoic, and 11-hydroxyoctadeca-cis,trans (trans,cis)-9,12-dienoic (unstable).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 710–716, November–December, 1976.     

Reaction of 1-alkyl-2-aryl-3-(2-methyl-2,3-epoxypropionyl)aziridines with boron trifluoride etherate in methanol

The reaction of boron trifluoride etherate in methanol with trans-1-methyl(ethyl)-or cis-1-cyclohexyl-2-aryl-3-(2-methyl-2,3-epoxypropionyl)aziridines leads to the formation of the corresponding boron fluoride complexes on the nitrogen atom of the aziridine ring. Reaction with trans-1-cyclohexyl-2-phenyl-3-(2-methyl-2,3-epoxypropionyl)aziridines occurs with stereospecific opening of the aziridine ring to give diastereomeric 2-methyl-5-methoxy-5-phenyl-4-cyclohexylamino-1,2-epoxypen-tan-3-ones, as well as products from the opening of the epoxide and aziridine rings — tetrahydrofuranones and tetrahydropyranones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 596–600, May, 1986.     

Synthesis,crystal structure and magnetic properties of a two-dimensional mixed-valence assembly [Fe(salen)]2[Fe(CN)5NO]

A cyanide-bridged Fe^III–Fe^II mixed-valence assembly, [Fe^III(salen)]₂[Fe^II(CN)₅NO] [salen = N,N-ethylenebis(salicylideneiminato)dianion], prepared by slow diffusion of an aqueous solution of Na₂[Fe(CN)₅NO] · 2H₂O and a MeOH solution of [Fe(salen)NO₃] in an H tube, has been characterized by X-ray structure analysis, i.r. spectra and magnetic measurements. The product assumes a two-dimensional network structure consisting of pillow-like octanuclear [—Fe^II—CN—Fe^III—NC—]₄ units with dimensions: Fe^II—C = 1.942(7) Å, C—N = 1.139(9) Å, Fe^III—N = 2.173(6) Å, Fe^II—C—N = 178.0(6)°, Fe^III—N—C = 163.4(6)°. The Fe^II—N—O bond angle is linear (180.0°). The variable temperature magnetic susceptibility, measured in the 4.8–300 K range, indicates the presence of a weak intralayer antiferromagnetic interaction and gives an Fe^III–Fe^III exchange integral of –0.033 cm^–1.     

Synthesis,stereochemistry, and isomeric transformations of cis- and trans-1,2-dimethyl-4-aryl-5-aroyl-2-imidazolines

The corresponding trans- and cis-1,2-dimethyl-4-aryl-5-aroyl-2-imidazolines were obtained from complexes of cis- and trans-1-methyl-2-aryl-3-aroylaziridines with BF₃ by heating with acetonitrile. The reaction proceeds with inversion of the configuration of the starting 3-aroylaziridines. In the presence of bases the complexes of cis-1,2-dimethyl-4-aryl-5-aroyl-2-imidazolines readily undergo isomerization to the corresponding trans analogs. The structures of the products were established on the basis of the IR, PMR, and mass spectra and the results of elementary analysis. The configurations of the compounds were determined by means of the Overhauser nuclear effect.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 952–957, July, 1981.     

Chemical transformations of 6-[(1-methyl-4-nitro-5-imidazolyl)-thio]purine (azathioprine)

The chemical transformations of 6-[(1-methyl-4-nitro-5-imidazolyl)thio]purine (azathiopurine) —hydrogenation, acetylation, alkylation by lower alkyl halides at positions 7 and 9 of the purine ring, hydrolytic cleavage at the C₍₆₎–S and S–C₍₅₎ bonds— were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 372–379, March, 2000.     

Chemometric deconvolution of gas chromatographic unresolved conjugated linoleic acid isomers triplet in milk samples

A generally known problem of GC separation of trans-7;cis-9; cis-9,trans-11; and trans-8,cis-10 CLA (conjugated linoleic acid) isomers was studied by GC–MS on 100 m capillary column coated with cyanopropyl silicone phase at isothermal column temperatures in a range of 140–170 °C. The resolution of these CLA isomers obtained at given conditions was not high enough for direct quantitative analysis, but it was, however, sufficient for the determination of their peak areas by commercial deconvolution software. Resolution factors of overlapped CLA isomers determined by the separation of a model CLA mixture prepared by mixing of a commercial CLA mixture and CLA isomer fraction obtained by the HPLC semi-preparative separation of milk fatty acids methyl esters were used to validate the deconvolution procedure. Developed deconvolution procedure allowed the determination of the content of studied CLA isomers in ewes’ and cows’ milk samples, where dominant isomer cis-9,trans-11 is eluted between two small isomers trans-7,cis-9 and trans-8,cis-10 (in the ratio up to 1:100).     

Insect pheromones and their analogues. XVI. Practical synthesis of hexadec-9Z-enal — A component of the sex pheromone of the cotton bollwormHeliothis armigera

A synthesis of hexadec-9Z-enal — a component of the sex pheromone of the cotton boll-wormHeliothis armigera (Hübner) — based on cyclooctene (I) is proposed. Through a solution of 22 g of (I), 250 ml of cyclohexane, and 40 ml of MeOH is passed (at 5°C) 0.2 M O₃/O₂, the solution is decanted off, and the precipitated ozonide is dissolved in 200 ml of MeOH and is reduced with 19 g of NaBH₄ (40°C) with the isolation, after the usual working up, of 23.4 g of octane-1,8-diol (II). From 0.5 mole of (II) and 0.6 mole of 45% HBr 8-bromooctan-1-ol (III) is obtained and this is converted into 1-(2-THPL)oxy)-8-bromooctane (IV). The condensation of (IV) with oct-1-yne (Ar, LiNH₂, HMPTA, 10°C, 1 h, and then 55°C, 10 h) leads to 1-(2-THPL-oxy)hexadec-9-yne (V) the hydrolysis of which (MeOH, H₂O, p-TsOH, 20°C for 20 h) yields hexadec-9-yn-ol (VI). The reduction of (VI) (Et₂O, iso-BuMgBr, Cp₂TiCl₂, 0°C, 15 min, then 20°C, 1 h) yieldshexadec-9Z-en-l-ol (VII). The oxidation of (VII) (PyHCrO ₃ ⁺ Cl^–, CH₂Cl₂, 20°C, 2 h) gives hexadex-9Z-enal (VIII). Characteristics of the compounds (yield (%), n _D ^{20 (25)}: (II) – 80, mp 61–62°C; (III) – 75, 1.4807; (IV) – 99, —; (V) – 52, 1,4650; (VI) – 85, 1.4657; (VII) – 99, 1.4650; (VIII) – 98, 1.4600. Characteristics of the IR and PMR spectra of compounds (V–VII) are given.Institute of Chemistry, Bashkir Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 286–289, March–April, 1987.     

Synthesis,stereochemistry, and isomeric transformations of 4-aryl-5-aroyl-2-methylthio-2-imidazolines

The corresponding 4-aryl-5-aroyl-2-methylthio-2-imidazolines were obtained by the reaction of complexes of cis- and trans-3-aroylaziridines and boron trifluoride with methyl thiocyanate. It is shown on the basis of spectral data that the aziridine ring is opened regiospecifically at the C(₂) atom and stereospecifically with inversion of the configuration.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1484–1488, November, 1988.     

Alkylation and reduction reactions in the isoquino[2,3-a]quinazoline series

Protonation and methylation of 5-oxo-7,12-dihydro-5H-isoquino[2,3-a]quinazoline occur at the N₍₆₎ atom, while methylation of 5-oxo- and 6-methyl-5-oxo-6,6a,7,12-tetrahydro-5H-isoquino[2,3-a]quinazolines takes place at the N₍₁₃₎ atom; the degree of stereoselectivity varies depending on the presence of a substituent attached to N₍₁₃₎. Based on PMR spectral analysis utilizing the nuclear Overhauser effect, we have established the structure and studied the conformational behavior of the tosylate derivatives of cis-13-methyl-, trans-13-methyl-, and cis-6,13-dimethyl-5-oxo-6,6a,7-12-tetrahydro-5H-isoquino[2,3-a]quinazolinium ions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 389–394, March 1991,     

Linear oligomerization of 1,3-pentadiene in presence of catalytic system CoCl2-PPh3-NaBH4

Conclusions The system CoCl₂-PPh₃₂-NaBH₄ catalyzes the oligomerization of trans-1,3-pentadiene to 4-methyl-2,5,7-nonatriene and the 1,3-pentadiene trimer. 4-Methyl-2,5,7-nonatriene is formed predominantly at 95°, while the trimer is the predominant product at 120°. This system does not catalyze the oligomerization of cis-1,3-pentadiene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, 1423–1425, June, 1978.     

B—Z bond dissociation energies of <Emphasis Type="Italic">para</Emphasis>-substituted phenylboranes: a problem for Nau's definition of polar ground-state effects

UB3LYP/6-311++g(2df,p) and RMP2/6-311++g(d,p) methods were used to calculate B—Z bond dissociation energies (BDE) of para-substituted phenylboranes (X—C₆H₄—BH—Z). It was found that the slopes () of regressions between B—Z BDEs and substituent _p constants increase in the order B—Cl (between –0.24 and 0.21 kcal/mol) < B—H (0.06-0.33 kcal/mol) < B—F (0.48-0.78 kcal/mol) < B—CH₃ (0.83–1.28 kcal/mol) < B—Li (2.62-3.73 kcal/mol). Since all the homolysis reactions give the same boron radical, the large variation of indicates that the substituent effects on energies of the ground-state molecules are important for the substituent effects on BDEs. However, the ground-state stabilization energies, calculated using either Nau's method or our method, do not show any correlation with the polarization of the B—Z bond as defined by the electronegativity difference between the group X—C₆H₄—BH and Z. Therefore, the theory that the remote substituent effects on Y—Z BDEs are dependent on the Y—Z polarity should be discarded.     

Komplexboride in den Systemen Hf−Mo−B und Hf−W−B

Zusammenfassung In den Dreistoffen: Hf–{Mo, W}–B werden ternäre Boride Hf₉Mo₃B_2-x und (Hf, W)₁₂B_2-x aufgefunden und strukturell charakterisiert. Gitterparameter und Atomparameter der K (Kappa)-Carbid-ähnlichen Phasen werden bestimmt. Die Schmelzgleichgewichte im System Hf–Mo–B werden fast vollständig ermittelt. Hafnium läßt sich in Hf₉Mo₃B_2-x etwa zur Hälfte durch Zirkonium ersetzen.

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Complex borides in the systems hafnium —(molybdenum, tungsten)—boron

Complex borides of formula Hf₉Mo₃B_2-x and (Hf, W)₁₂B_2-x have been detected within the ternary systems: Hf–{Mo, W}–B. The lattice and atomic parameters of the K (Kappa) carbide like phases have been determined. Most of the reaction equilibria of the ternary system: Hf–Mo–B have been derived. Hafnium can be substituted by zirconium within Hf₉Mo₃B_2-x up to (Hf_0.5Zr_0.5)₉Mo₃B_2-x .

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