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101.
Conformational isomerism has been studied by ab initio methods (RHF/6-31+G*, MP2/6-31+G*) for CH2=CHCH2X heteroallyl and CH3CH=CHX heteropropenyl systems (X = H, Me, NMe2, OMe, PMe2, SMe, ONCH2). In 3-heteroprop-1-enes, substituents preferably occupy the AC position relative to the C=C double bond. The E isomers of 1-methylthio- and 1-methoxyprop-1-enes, which are thermodynamically more stable, have two stable forms, SP and AC; for 1-dimethylamino- and 1-imethylphosphinoprop-1-enes, the stable forms are AP and SC. The molecule of the E isomer of formoxime propenyl ether exists in two stable rotamer forms, SC and AP, the latter being predominant. The Z isomers preferably exist in the form of AC (X = CH3O, CH3S) and AP (X = (CH3)2N, (CH3)2P, CH2=NO) conformations. Migration of the double bond toward an heteroatom in formoxime allyl ether, forming the E and Z isomers, is energetically favorable, the Z isomer being thermodynamically preferable. 相似文献
102.
Nina A. Nedolya Nataly I. Schlyakhtina Lyudmila V. Klyba Igor A. Ushakov Sergei V. Fedorov Lambert Brandsma 《Tetrahedron letters》2002,43(52):9679-9681
Reaction of lithiated methoxyallene, 1-ethoxyethoxyallene, 1-(methylthio)propyne and 2-butyne with methoxymethyl isothiocyanate, MeOCH2N=C=S followed by methylation affords the imidothioates H2C=C=C(R)C(SMe)=NCH2OMe [R=Me, OMe, OCH(Me)OEt, SMe]. Rearrangement to the fully conjugated systems H2C=CH---C(R)=C(SMe)---N=CHOMe and subsequent electrocyclisation of these compounds leads to the 5-substituted 6-(methylthio)-2-methoxy-2,3-dihydropyridines with good to excellent yields. In the presence of acidic catalysts or by heating at elevated temperatures these dihydropyridines eliminate methanol to afford 3-substituted 2-(methylthio)pyridines. The aroma compound 2-(methylthio)-3-pyridinol was obtained by acid-catalysed treatment of 3-(1-ethoxyethoxy)-2-(methylthio)pyridine. 相似文献
103.
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107.
V. Yu. Vshivtsev E. P. Levanova V. A. Grabel’nykh E. A. Sukhomazova A. I. Albanov L. V. Klyba E. R. Zhanchipova N. V. Russavskaya N. A. Kochervin 《Russian Journal of General Chemistry》2008,78(4):608-613
Ethylene chlorohydrin when reacted with elemental chalcogens or dimethyl dichalcogenides in the hydrazine hydrate-alkali system forms chalcogen-containing analogs of ethylene glycol and its derivatives (dichalcogenated β-diglycols, chalcogenated ethanols, and chalcogenated methyl cellosolves). 相似文献
108.
L. V. Klyba N. A. Nedolya O. A. Tarasova E. R. Zhanchipova O. G. Volostnykh 《Russian Journal of Organic Chemistry》2009,45(4):596-608
The electron impact mass spectra of previously unknown 2-alkyl-6-alkoxy-, 2,3-trimethylene-6-alkoxy- and 2-alkyl-6-aryl(hetaryl)-3H-azepines were studied. All compounds give rise to stable molecular ions (I
rel = 44–100%) whose fragmentation pattern is determined mainly by the substituent on C6. Decomposition of the molecular ions derived from 6-alkoxy derivatives (R1 = MeO, EtO, i-PrO) follows general relations typical of alkyl ethers. The main characteristic peaks in the mass spectra of 2-methyl-6-aryl-
and 2-methyl-6-hetaryl-3H-azepines (R1 = Ph, 1H-pyrrol-1-yl, 5-methylthiophen-2-yl) belong to even-electron rearrangement ions [M − H]+ and [M − Me]+, which have conjugated bi- and tricyclic structures, and products of their subsequent decomposition. Substituents in positions
2 (R2) and 3 (R4) [R4 = H, R2 = Me, Et; R2R4 = (CH2)3] bring some specificity to the fragmentation pattern, but their contribution is not crucial.
Original Russian Text ? L.V. Klyba, N.A. Nedolya, O.A. Tarasova, E.R. Zhanchipova, O.G. Volostnykh, 2009, published in Zhurnal
Organicheskoi Khimii, 2009, Vol. 45, No. 4, pp. 610–621.
For communication VII, see [1]. 相似文献
109.
110.
E. P. Levanova V. A. Grabel’nykh V. S. Vakhrina N. V. Russavskaya A. I. Albanov L. V. Klyba N. A. Korchevin I. B. Rozentsveig 《Russian Journal of Organic Chemistry》2014,50(1):6-12
The direction of the reaction of propane-1,3-dichalcogenolates with 2,3-dichloroprop-1-ene in the system hydrazine hydrate-KOH depends not only on the conditions but to a greater extent on the chalcogen nature. Dipotassium propane-1,3-dithiolate and propane-1,3-diselenolate give rise to products of substitution of the chlorine atom on the sp 3-carbon atom, which are capable of undergoing further transformations (domino reaction). Dipotassium propane-1,3-ditellurolate promotes elimination of both chlorine atoms with formation of allene. 相似文献