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1.
Some bridgehead nitrogen compounds possessing the CH(Me)-bridgehead N? C(O) system have been synthesised and their configurations assigned. The chemical shifts of the proton geminal to the methyl group provides evidence for the existence of a deformed chair conformation for the methyl substituted ring. 相似文献
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A. S. Gazizov M. S. Khakimov A. R. Burilov M. A. Pudovik D. B. Krivolapov I. A. Litvinov A. I. Konovalov 《Russian Chemical Bulletin》2009,58(1):238-240
The reaction of 1-(2,2-dimethoxyethyl)-1,3,3-trimethylurea with 2-methylresorcinol in dioxane in the presence of trifluoromethanesulfonic
acid affords a new type of imidazolidin-2-ones, viz., 5-(2,4-dihydroxy-3-methylphenyl)-1,1,3-trimethyl-2-oxoimidazolidinium triflate containing an endocyclic ammonium nitrogen
atom. 相似文献
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[reaction: see text] A fused four-membered ring has a powerful directing ability in effecting the regioselective reactions of benzyne with ketene silyl acetal, nucleophile, and alpha-alkoxyfuran. 相似文献
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Conclusions The selectivity of the nitrosation of cholinelike alkylureas is explained in terms of the theory of boundary orbitals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 369–371, February, 1985. 相似文献
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Ernest L. Eliel William H. Pearson Linda M. Jewell Anthony G. Abatjoglou William R. Kenan 《Tetrahedron letters》1980,21(4):331-334
Neighboring group participation via four-membered ring intermediates resulting in complete rearrangement occurs in the methanolysis of R1R2C(SCH2C6H5)CH2CH(R3)OTs when R1=R2=R3=Me and when R1=R2=Me, R3=H. No rearrangement is found for R1=R2=R3=H or R1=R2=H, R3=Me. The case of R1=Me, R2=R3=H is intermediate. 相似文献
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Tang RY Xie YX Xie YL Xiang JN Li JH 《Chemical communications (Cambridge, England)》2011,47(48):12867-12869
The first example of molecular sieve-promoted TBHP-mediated direct oxidative thiolation of an sp(3) C-H bond adjacent to a nitrogen atom with disulfides under metal-free conditions, which allows for preparation of numerous S,N-containing compounds, is presented. Moreover, diverse benzothiazoles and a fipronil analog can be synthesized through this strategy. 相似文献
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Jitsuo Kiji Susumu Yoshikawa Eiichi Sasakawa Satoshi Nishimura Junji Furukawa 《Journal of organometallic chemistry》1974,80(2):267-274
Reaction of butadiene with strained ring olefins such as norbornene, dicyclopentadiene etc. Gives an exo-methylene- and methyl-substituted four-membered cyclic compound (II). The effective catalysts are (n-Bu3P)2NiBr2/NaBH4 or /alkoxide syn-π-crotylbis(triethyl phosphite)nickel hexafluorophosphate (IV), and tetrakis(triethyl phosphite)nickel/CF3COOH . π-Crotyl complex IV reacts with the strained ring olefins to give the corresponding product similarly. It is concluded that the active species for this catalytic reaction is a nickel hydride and that this reaction proceeds through π-crotyl intermediate. 相似文献
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Pyrolytic conversion of [1,2,4]triazino[3,4-b][1,3,4]thiadiazin-4-ones, [1,3,4]thiadiazino[2,3-b]quinazolin-10-ones and [1,2,4]triazolo[3,4-b][1,3,4]thiadiazines into their corresponding pyrazolo[5,1-c][1,2,4]triazin-4-ones, pyrazolo[4,3-b]quinazolin-9-ones and pyrazolo[5,1-b][1,2,4]triazoles via desulfurization ring contraction is described. The starting condensed 1,3,4-thiadiazines were prepared from the corresponding readily available 4-amino-3-thioxo-1,2,4-triazin-5(4H)-ones, 3-amino-2,3-dihydro-2-thioxoquinazolin-4(1H)-one and 4-amino-3(2H)-thioxo-1,2,4-triazoles upon reaction with the appropriate α-haloketones in two steps, or directly in one step in ethylpyridinium tetrafluoroborate (ionic liquid, IL). 相似文献
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A number of cyclobutane derivatives containing one or more double bonds in endo- or exocyclic positions have been studied by the molecular mechanics method within the context of the MM2 force field. Generally speaking, the structures and energies of these compounds are well calculated in cases in which they are known experimentally and are predicted in others. Examples are shown of the use of the moments of inertia of molecules, which are known from microwave studies, in conjunction with molecular mechanics calculations to yield better structures than could be obtained by either method alone. Compounds examined include cyclobutene, methylenecyclobutane, Dewar benzene, and related compounds. 相似文献
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G. E. Trukhan Ya. R. Tymyanskii Yu. P. Andreichikov M. I. Knyazhanskii G. N. Dorofeenko 《Chemistry of Heterocyclic Compounds》1978,14(9):990-993
Nitro and amino derivatives of pyrido[1,2-f]phenanthridinium perchlorate were synthesized by the Pschorr method and by photocyclodehydrogenation from N-(nitrophenyl)-or N-(aminophenyl)pyridinium perchlorates. The mechanism of the photoconversion was investigated.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1226–1229, September, 1978. 相似文献
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The cyclization of (4-quinazolinylthio)phenylacetic and acetic acids gives extremely reactive thiazolo[3,2-c]quinazolinium 3-oxides, which, depending on the structure of the mesoionic ring, react with either electrophilic or nucleophilic reagents.See [1] for Communication 16.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 408–412, March, 1989. 相似文献
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Very low pressure vapor phase pyrolysis (flash thermolysis) of four-membered ring compounds was followed by microwave spectroscopic detection of the reaction products. The molecules studied included substituted cyclobutanes, thietanes, oxetane and azetidine. Microwave spectroscopy is well suited not only to observe stable reaction products but also to detect unstable species formed during pyrolysis. The investigation provided a wealth of information on typical decomposition patterns during pyrolysis of four-membered ring compounds. In addition, new methods were found for producing some unstable molecules with improved efficiency. 相似文献