共查询到20条相似文献,搜索用时 15 毫秒
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Conclusions Depending on the conditions, 3-methoxy-1,3,5(10)-8,14-secoestratriene-14,17-dione (III) under the influence of acid agents is cyclized to estradiol, equilenol, 18-norequilenane, and cyclopentanophenanthrene derivatives. As a result, the spatial factor determines the course of the reaction even if the 9(11)-double bond, which activates the H atoms at C7, is absent.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1628–1632, July, 1973. 相似文献
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The acylation of the (±)-spiro-γ-lactone 1 lithium enolate (3 equiv) by the O-TBDMS methyl (−)-(S)-lactate, the O-TBDMS methyl (+)-(S)-mandelate, or the diacetone-d-glucose carbonate (1 equiv each) occurs with a kinetic resolution. The (S,S)-enolate is the most reactive with the lactate and it is the (R,R)-enolate, which selectively reacts with the mandelate or the DAG carbonate. After alkylation of the resulting acyl lactones with 4- or 5-methoxy-1-iodobenzocyclobutene and heating, title compounds were obtained and, after deprotection, the structures of the optically pure new steroids were ascertained by single crystal X-ray analysis. 相似文献
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Kuznetsov Yu. V. Levina I. S. Shashkov A. S. Zavarzin I. V. 《Russian Chemical Bulletin》2018,67(11):2112-2120
Russian Chemical Bulletin - An efficient preparative method for the synthesis of 3-methoxy-19-norpregna-1,3,5(10), 16-tetraen-20-one was suggested. This compound is a key intermediate product in... 相似文献
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V. V. Bakharev A. A. Gidaspov E. V. Golovin 《Russian Journal of General Chemistry》2007,77(8):1426-1429
Fragmentation of 6-fluoro(chloro, bromo)dinitromethyl-, 6-trinitromethyl-, 6-(1,1-dinitroethyl)-, and 6-(2-hydroxy-1,1-dinitroethyl)-2-dimethylamino-4-methoxy-1,3,5-triazines under electron impact was studied. The stability of the molecular ions and main fragmentation pathways are discussed. 相似文献
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The twelve tri-N-sulphonylhexahydro-1,3,5-triazines (R = alkyl or aryl) exhibit a common fragmentation pattern; most of the fragments are directly or indirectly generated from the [M ? RSO2]+ ion. Tri-N-Benzylsulphonylhexahydro-1,3,5-triazine (R = PhCH2) departs from the others mainly because the key ion [M ? RSO2]+ suffers a skeletal rearrangement with loss of SO2. The rationalizations presented are supported by metastable evidence, accurate mass measurements and deuterium labelling. 相似文献
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This paper reports the mass spectrum of vinyltrimethylsilane over the range of electron-impact energy of 9 to 70 eV as determined with a quadrupole mass spectrometer. Less extensive data obtained with magnetic spectrometers are included for comparison as well as the spectrum of vinyl-tri(methyl-d3)silane. Plots of ion intensity as a function of electron energy, nominal appearance potentials and metastable ion transitions are given. The primary ionization results in an electron deficiency on the silicon atom, followed by loss of either ·CH3, C2H4 or ·C2H3 to give fragments of mass 85, 73 or 72, respectively. The primary fragment of mass 85 loses C2H2 to give the mass 59 ion. The primary fragment of mass 73 loses successively C2H4 and H2 to give first the mass 45 ion and then the mass 43 ion. At 15 eV, the relative intensities of the ions are 85 > 72 > 100 > 59 > 73. At 70 eV, the relative intensities are 59 > 85 > 43 > 45 > 73 > 72 > 100. 相似文献
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Monotransmetallation of 2,5-bis(trimethylstannyl)thiophene followed by the addition of estrone 3-methyl ether and iodine yields 3-methoxy-17α,-(5-iodothien-2-yl)estra-1,3,5(10)trien-17β-ol. 相似文献
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Zh. K. Torosyan S. D. Mikhno V. A. Zamureenko N. S. Kulachkina R. G. Kostyanovskii V. M. Berezovskii 《Chemistry of Heterocyclic Compounds》1976,12(4):391-396
The mass spectra of cis- and trans-4-acylamino-3-hydroxy(or acyloxy)thiophans were investigated. The general principles of fragmentation under the influence of electron impact were established. A difference in the intensities of the peaks of the fragments formed at an ionizing-electron energy of 14 eV was observed for some of the cis and trans isomers of 3,4-substituted thiophans.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 466–471, April, 1976. 相似文献
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The first total synthesis of 3-aza-11-thia-1,3,5(10)-trieno steroids was achieved via an intramolecular Diels-Alder cycloaddition of o-quinodimethanes as the key step. 相似文献
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[reaction: see text] Novel two-dimensional octupoles containing donors at the core and acceptors at the edge of peripheral groups were synthesized by Horner-Wittig reactions. These chromophores show very large first hyperpolarizability and good thermal stability and are attractive candidates for nonlinear optical materials. 相似文献