排序方式: 共有7条查询结果,搜索用时 15 毫秒
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Trost BM Jaratjaroonphong J Reutrakul V 《Journal of the American Chemical Society》2006,128(9):2778-2779
The use of imines bearing a hydrolyzable nitrogen substituent in direct asymmetric Mannich reactions with alpha-hydroxyketones is developed. Previous work focused on the use of N-arylimines or nonenolizable imines, and the latter with only methoxy-substituted alpha-hydroxyacetophenones. Using a dinuclear catalyst devised from 2,6-di-(S)-2'-diphenylhydroxymethylpyrrolidino-N-methyl)-4-methylphenol and diethylzinc, a broad array of hydroxyacetylated aromatics, including phenyl, 2-furyl, 1-naphthyl, and 2-naphthyl, react well. In addition, the reactions focused on the use of enolizable imines. With the N-diphenylphosphinoyl, the reactions are anti selective with enantiomeric excesses ranging from 83 to 99%, except for the reaction of the 2-methoxy-2'-hydroxyacetylbenzene. With the N-Boc-imines, the reactions were syn selective with enantiomeric excesses from 90 to 94%. The dependence of the diastereoselectivity on the nature of the N-substituent presumably arises from the steric demands of the diphenylphosphinoyl group. 相似文献
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Paul Jaray 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1958,9(5-6):382-388
Summary The importance of aerodynamics in mechanical engineering is discussed. The influence on the design of vehicles, especially
automobiles, is considered in detail. The danger of carbon monoxide poisoning is pointed out. This occurs in vehicles of poor
aerodynamic form and is due to bad ventilation. Many advances in mechanical engineering rendered possible by the application
of aerodynamics are also discussed.
相似文献
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Jaray Jaratjaroonphong Suppachai Krajangsri Vichai Reutrakul 《Tetrahedron letters》2012,53(19):2476-2479
Iodine is shown to be an efficient catalyst for a one-step, three-component aza-Friedel–Crafts reaction of activated arenes or heteroarenes with benzyl or tert-butyl carbamates in combination with a wide variety of aldehydes in toluene under ‘open-flask’ and mild conditions. In the presence of 5 mol % of iodine in toluene at room temperature, the reaction gives the corresponding N-CBz or N-Boc protected α-branched amines, selectively, in good to excellent yields. 相似文献
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Surisa Tuengpanya Chayamon Chantana Uthaiwan Sirion Wipada Siritanyong Klaokwan Srisook Jaray Jaratjaroonphong 《Tetrahedron》2018,74(33):4373-4380
A convenient, practical and highly efficient one-pot method has been developed for the synthesis of triaryl- and triheteroarylmethane derivatives by Bi(OTf)3-catalyzed Friedel-Crafts alkylation of trialkyl orthoformates in combination with a wide variety of arenes/heteroarenes at room temperature under solvent-free conditions and in an air atmosphere. The methodology offers an operational simplicity, high atom economy and environmentally benign procedure. Furthermore, selected compound 3k showed promising anti-inflammatory activity with inhibition nitric oxide and did not exhibit significant cytotoxic effects on macrophage cells. 相似文献
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Darunee Soorukram Jaray PanmuangPatoomratana Tuchinda Chutima KuhakarnVichai Reutrakul Manat Pohmakotr 《Tetrahedron》2014
A stereoselective approach to secolignans is described. The key synthetic strategy involves an asymmetric aldol reaction to control the creation of the stereogenic center at the β-carbon of the target secolignans. In the present work, peperomin C and its analogues, i.e., 2,6-didehydropeperomin C and 2-epi-peperomin C were successfully synthesized in good yields with high stereoselectivities. 相似文献
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Jaray Jaratjaroonphong Supaporn Sathalalai Vichai Reutrakul 《Tetrahedron letters》2009,50(44):6012-3245
Iodine is shown to be an efficient catalyst for the Friedel-Crafts alkylation of arenes with a wide variety of aldehydes in toluene under ‘open-flask’ and mild conditions. In the presence of 10 mol % of iodine, the reaction of arenes with aromatic aldehydes gives the corresponding triarylmethane derivatives (TRAMs), regioselectively, in good to excellent yields. On the other hand, a series of diarylalkane derivatives is synthesized smoothly by the reaction with aliphatic aldehydes. 相似文献
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Warapong Senapak Rungnapha Saeeng Jaray Jaratjaroonphong Vinich Promarak Uthaiwan Sirion 《Tetrahedron》2019,75(26):3543-3552
A novel efficient method for the selective synthesis of 2-substituted benzimidazoles is described through condensation reaction of o-phenylenediamines with a wide rang of aliphatic, aromatic and heteroaromatic aldehyde substrates using Brönsted acidic ionic liquid as a reusable catalyst under metal-free conditions at ambient temperature. Notably, Dodecylimidazolium hydrogen sulfate ([DodecIm][HSO4]) is the most efficient catalyst for good to excellent yields of the corresponding products (up to 98%). Subsequently, this protocol was successfully applied for the preparation of N-alkylated 1,2-disubstituted benzimidazoles in high to excellent yields via sequential one-pot reaction. In addition, catalysts are recycled at least four times without significant loss in activity. 相似文献
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