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991.
M. S. Yusubov G. A. Zholobova I. L. Filimonova Ki-Whan Chi 《Russian Chemical Bulletin》2004,53(8):1735-1742
Treatment of alkenes and alkynes with diacetoxyiodobenzene activated by mineral and organic acids predominantly results in oxidative rearrangement. 1,4-Diphenylbutadiene in MeOH gives 3,4-dimethoxy-1,4-diphenylbut-1-ene.Published in Russian in Izvestiya Akademii Nauk.
Seriya Khimicheskaya, No. 8, pp. 1669–1675, August, 2004. 相似文献
992.
The reaction of cyclopentylidenecyanothiocetamide with cyanothioacetamide andN-methylmorpholine gaveN-methylmorpholinium 6-amino-3,5-dicyano-1,4-dihydropyridine-4-spirocyclopentane-2-thiolate, which was used in the syntheses
of substituted 2-alkylthiodihydropyridines and pyrazolodihydropyridine.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1849–1851, October. 1997. 相似文献
993.
The regioselective Claisen rearrangement of resorcinol allyl ethers with boron trichloride was achieved with good selectivity (ca. 13:1) to afford the 6-isomer as major product. 相似文献
994.
Ayako Torikai Takuya Mitsuoka Kenji Fueki 《Journal of polymer science. Part A, Polymer chemistry》1993,31(11):2785-2788
Bisphenol A polycarbonate (PC) was irradiated with monochromatic light of wavelengths 260, 280, 300, 320, 340, 400, and 500 nm by use of the Okazaki large spectrograph (OLS). The quantum yield of main-chain scission (?cs), efficiency of photo-Fries rearrangement (Er), and effects of wavelength on ?cs and Er were investigated. It was found that photodegradation and photo-Fries rearrangement of PC took place by the irradiation of 260–300 nm light, but did not by the irradiation at λ ≧ 320 nm. The ?cs has a maximum value in the case of the irradiation with 260 nm light, while Er was found to have a maximum value by the irradiation of 280 nm light. © 1993 John Wiley & Sons, Inc. 相似文献
995.
A new optically active diisocyanate was prepared from the reaction of l-leucine and pyromellitic dianhydride (PMDA) and subsequent transformation of intermediate imide-containing diacid to diisocyanate via Weinstock modification of Curtius rearrangement. Solution polycondensation reaction of the prepared diisocyanate with PMDA, 3,3,4,4-benzophenonetetracarboxylic dianhydride, and hexafluoroisopropylidene 2,2-bis(phthalic anhydride) resulted in the preparation of novel optically active polyimides. The optimal conditions for polyimidations (reaction duration and temperature programming) were obtained via study of the model compound. The monomer, model compound and polymers were characterized by FTIR, 1HNMR, mass spectroscopy and elemental analysis and their optical and physical properties were studied as well. 相似文献
996.
1-Substituted 1,2,3,4-tetrahydroisoquinoline systems were prepared by reaction of cotarnine with the NH-and CH-acids methyl-
and acyl derivatives of pyrazole and 1,3-dicarbonyl reagents. Depending on the structure and reaction conditions, bifunctional
pyrazole nucleophiles can give substitution products at the N atom, methyl, or acyl group; 1,3-diketones, at the terminal
methyl. Rearrangements occurring during the reaction of cotarnine with bifunctional substrates were studied.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 360–364, July–August, 2005. 相似文献
997.
A concise synthetic strategy toward cyclic α,α-disubstituted α-amino acids, 1-substituted 4-aminopiperidine-4-carboxylic acids have been developed. The synthetic route is a reductive amination of dimethyl bis(dioxolanemethyl)malonate with various amines, followed by Curtius rearrangement. This synthetic route is capable of synthesizing 4-aminopiperidine-4-carboxylic acids bearing a bulky substituent and optically active ones bearing a pendent chiral substituent, by the change of condensed amines. 相似文献
998.
Gonzalo Blay 《Tetrahedron》2005,61(46):10853-10860
The synthesis of the spirocyclic sesquiterpenes (−)-gleenol and (−)-axenol in enantiomerically pure form has been achieved starting from R-(−)-carvone. The key step is the silicon guided acid-promoted rearrangement of a 9-trimethylsilyl-5,6-epoxy-noreudesmane prepared from 3-trimethylsilyldihydrocarvone in several steps involving Robinson annulation, enone deconjugation and epoxidation. Acid treatment of the epoxy-noreudesmane gave a norspiroaxane as the main product, which was used as intermediate for the synthesis of two naturally occurring sesquiterpenes gleenol and axenol. 相似文献
999.
对比了不同孔径的钛硅分子筛催化剂Ti-MCM-41(Si/Ti摩尔比=27)和TS-1(Si/Ti摩尔比=25)对环己酮肟气相贝克曼重排反应的催化性能,分析了它们在重排反应中的积碳量和孔体积的变化.结果表明,这些钛硅分子筛催化剂的失活主要是由积碳引起的,且积碳速率受催化剂孔径的制约.在重排反应过程中,TS-1催化剂微孔孔道内的积碳量随反应时间线性增加,微孔体积随反应时间线性下降;而二次孔内的积碳量随反应时间呈指数增加,孔体积随反应时间呈指数递减. 相似文献
1000.
Ryabova S. Yu. Alekseeva L. M. Lisitza E. A. Shashkov A. S. Chernyshev V. V. Tichomirova G. B. Goyzman M. S. Granik V. G. 《Russian Chemical Bulletin》2001,50(8):1449-1456
The possibility of transformation of 3-cyano-1-p-nitrophenyl--carbolin-2-one into 2-amino-3-cyano-1-p-nitrophenyl-1H-pyrido[3,2-b]indole derivatives and 2-imino-3-cyano-1-p-nitrophenyl-5H-pyrido[3,2-b]indole derivatives (-carbolines) is demonstrated. Methylation of 1-p-nitrophenyl-2-piperidino-1H--carboline followed by treatment with acetone in an alkaline medium yields 4-acetonyl-5-methyl-1,4-dihydro-5H-pyrido[3,2-b]indole derivative. The rearrangement of 2-arylimino-3-cyano-1-p-nitrophenyl-5H-pyrido[3,2-b]indoles into 2-(aryl)nitrophenylamino-3-cyano-5H-pyrido[3,2-b]indoles was accomplished on heating above the melting point or on treatment with potassium tert-butoxide. The structures of the resulting compounds were proved by 1H and 13C NMR spectroscopy and X-ray diffraction analysis. 相似文献