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1.
Liquid-phase synthesis of 2-substituted benzimidazoles, benzoxazoles and benzothiazoles 总被引:1,自引:0,他引:1
A novel acid fluoride for use in the liquid-phase synthesis of substituted benzimidazoles, benzoxazoles and benzothiazoles was developed. Its synthetic utility is exemplified by a structurally diverse set of aromatic heterocycles. Final cleavage is achieved by treatment with sodium methoxide in methanol for 12 h. The corresponding benzimidazoles, benzoxazoles and benzothiazoles were obtained in good isolated yields (22-62%, four steps). 相似文献
2.
Solvent-free oxidative synthesis of benzimidazoles, benzoxazoles, and benzothiazoles from aromatic primary amines and o-phenylenediamine, o-aminophenol, and o-aminothiophenol has been achieved by using Fe(NO3)3 and TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxyl). This reaction can use air as an economical and green oxidant, and a wide variety of derivatives were obtained in good to excellent yields. The reaction mechanism was proposed and this method provides a direct, practical, and efficient approach for the preparation of substituted benzimidazoles, benzoxazoles, and benzothiazoles. 相似文献
3.
Ying Guo Dr. Wei David Wang Shengyu Li Yin Zhu Xiaoyu Wang Xiao Liu Prof. Dr. Yuan Zhang 《化学:亚洲杂志》2021,16(22):3689-3694
The properties of high stability, periodic porosity, and tunable nature of ordered mesoporous polymers make these materials ideal catalytic nanoreactors. However, their application in organocatalysis has been rarely explored. We report herein for the first time the incorporation of a versatile organocatalyst, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), into the pores of an FDU-type mesoporous polymer via a pore surface engineering strategy. The resulting FDU-15-TEMPO possesses a highly ordered mesoporous organic framework and enhanced stability, and shows excellent catalytic activity in the selective oxidation of alcohols and aerobic oxidative synthesis of 2-substituted benzoxazoles, benzimidazoles and benzothiazoles. Moreover, the catalyst can be easily recovered and reused for up to 7 consecutive cycles. 相似文献
4.
Robert Faure Jean-Pierre Galy Emile-Jean Vincent Jos Elguero 《Journal of heterocyclic chemistry》1977,14(8):1299-1304
The substituent effects on azido/tetrazole equilibrium on a series of 2-substituted thiazoles, benzothiazoles, thiadiazoles, benzoxazoles and isoxazoles has been studied by proton magnetic resonance in two solvents (DMSO-d6 and deuteriochloroform). For thiazole an excellent Hammett relationship was found, both for the 4 and 5 positions. 相似文献
5.
Solvent‐free oxidative synthesis of benzimidazoles, benzoxazoles and benzothiazoles from aromatic alcohols and o‐phenylenediamine, o‐aminophenol and o‐aminothiophenol has been achieved by using CuCl, 2,2′‐bipyridine and TEMPO (2,2,6,6‐tetramethylpiperidine‐1‐oxyl). The reaction proceeds via a dehydrogenation in open air at room temperature, and a wide variety of derivatives were obtained in good to excellent yields. The reaction mechanism was proposed and this method provides a mild and efficient access to substituted benzimidazoles, benzoxazoles and benzothiazoles. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
6.
A highly efficient palladium-catalyzed direct desulfitative arylation of azoles at C2-position has been developed using sodium arylsulfinates as aryl sources. Azoles including benzoxazoles, benzothiazoles, oxazoles, thiazoles, and 1,3,4-oxadiazoles reacted with sodium arylsulfinates smoothly to generate the corresponding products in good to excellent yields, and various substitution patterns were tolerated toward the reaction. 相似文献
7.
Nadale K. Downer-Riley 《Tetrahedron》2007,63(41):10276-10281
Synthesis of benzothiazoles by reaction of iodine with thiobenzamides, which do not possess an ortho alkoxy or ester group, is described. The unlikely synthesis of benzoxazoles from reaction of 2-alkoxythiobenzamides with iodine is also reported. 相似文献
8.
《Journal of heterocyclic chemistry》2017,54(6):3490-3497
New heterocycles containing 2‐aminopyrimidine moiety linked with pyrazino[1,2‐c ]pyrimidines, thieno[2,3‐d ]pyrimidines, benzimidazoles, benzothiazoles, and benzoxazoles have been prepared by an efficient method starting from N ‐(pyrimidin‐2‐yl)cyanamides. 相似文献
9.
A series of substituted benzimidazoles, benzothiazoles, and benzoxazoles was synthesized by combining 1,2-phenylenediamine, 2-aminothiophenol, or 2-aminophenol with aryl, heteroaryl, aliphatic, α,β-unsaturated aldehydes in the presence of nano ceria (CeO2) as an efficient heterogeneous catalyst. 相似文献
10.
The mass spectra of twenty-eight N-substituted 2-aminobenzoxazoles and 2-aminobenzothiazoles have been recorded and the identity of various ions in the mass spectra have been established by high resolution measurement. The molecular compound of series, benzoxazole, undergoes loss of hydrogen cyanide and carbon monoxide from the molecular ion as the most important decomposition pathways. The mass spectra of N-substituted benzothiazoles showed a similar fragmentation as that of N-substituted benzoxazoles. 相似文献
11.
Electrochemical Synthesis of Benzazoles from Alcohols and o‐Substituted Anilines with a Catalytic Amount of CoII Salt
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Yin‐Long Lai Prof. Dr. Jian‐Shan Ye Prof. Dr. Jing‐Mei Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(15):5425-5429
An electrochemical synthesis of benzazoles directly from alcohols and o‐substituted anilines has been developed. The reaction conditions have been optimized by varying the composition of the electrolyte and the metal salt used as catalyst. The cyclization proceeds smoothly with a catalytic amount of a cobalt salt under air at room temperature to afford 2‐substituted benzimidazoles, benzothiazoles, and benzoxazoles in good to excellent yields with a wide substrate scope. 相似文献
12.
We report the simple and efficient synthesis of 2-arylbenzothiazoles (‘BTA’) and 2-arylbenzoxazoles by direct coupling of benzothiazoles or benzoxazoles with aryl bromides. This method permits direct one-step access to precursors of radiolabeled BTA-1 and BTA-2 and their 6-methoxy analogues, used for in vivo imaging of β-amyloid plaques with positron emission tomography (PET). 相似文献
13.
Hideaki Hioki Kimihito Matsushita Miwa Kubo Kenichi Harada Mitsuaki Kodama Yoshiyasu Fukuyama 《Tetrahedron》2007,63(46):11315-11324
New methodology for the solid-phase synthesis of benzothiazoles, benzimidazoles, and benzoxazoles has been developed by using a traceless 4-alkoxy-aniline linker. The desired products were released from the polymer support by imine-exchange process coupled with air oxidation. Combinatorial library consisting of 36 members has been synthesized using this linker. The yields are low to good, which highly depend on the building blocks. Recycling of the polymer support was also investigated. 相似文献
14.
Vijaya Babu Kummari Kalavakuntla Chiranjeevi Alleni Suman Kumar Rathod Aravind Kumar 《合成通讯》2013,43(23):3335-3342
An efficient method for the synthesis of benzoxazoles and benzothiazoles via montmorillonite KSF clay catalyzed condensation reaction between 2-aminophenols or 2-aminothiophenols and β-diketones is reported. The efficiency of the reaction reflects from the wide substrate scope with electronic differentiation on aryls. The reaction is metal free and proceeds without the exclusion of air or moisture, and further the catalyst can be recycled up to 3–5 catalytic cycles. 相似文献
15.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(6):1552-1556
An iridium‐catalyzed intramolecular asymmetric allylic dearomatization reaction of benzoxazoles, benzothiazoles, and benzimidazoles was developed. The reaction was found to be compatible with a wide range of five‐membered‐ring electron‐deficient heteroaromatic compounds and furnished the corresponding dearomatized heterocycles in high yield with excellent enantioselectivity. 相似文献
16.
《Tetrahedron letters》2019,60(40):151082
The irdium-catalyzed intramolecular arylcarbon-hetero cross-coupling reactions with o-haloarylamides or o-haloarylamidine have been effectively achieved using KOAc and just 1 mol% catalyst. The [Ir(cod)Cl]2 was proved to be more potential for smoothly assembling functional structures benzimidazoles, benzoxazoles and benzothiazoles, which was superior to Cu- and Pd-catalyzed systems. Simultaneously, a concise and efficient synthesis of tafamidis was developed in 5-g scale. 相似文献
17.
Julia H. Spatz Thorsten Bach Julien Bardin Christoph Burdack 《Tetrahedron letters》2007,48(51):9030-9034
A combinatorial synthetic route yielding benzoxazoles and benzothiazoles is described. The use of o-halophenylisocyanides in the Ugi reaction (U-4CR) followed by a copper-catalyzed cyclization affords the benzoxazole as well as the benzothiazole moiety in good yield and high diversity. 相似文献
18.
A facile synthetic route for benzimidazoles, benzothiazoles and benzoxazoles comprising the reaction of corresponding o-phenylenediamine, o-aminothiophenol and o-aminophenol with various aldehydes using silica supported nano-copper (II) oxide as a catalyst has been described. The catalyst exhibited a clean reaction profile with excellent yields in a short reaction time. The catalyst can be recycled effectively after use. 相似文献
19.
《Angewandte Chemie (International ed. in English)》2017,56(6):1530-1534
An iridium‐catalyzed intramolecular asymmetric allylic dearomatization reaction of benzoxazoles, benzothiazoles, and benzimidazoles was developed. The reaction was found to be compatible with a wide range of five‐membered‐ring electron‐deficient heteroaromatic compounds and furnished the corresponding dearomatized heterocycles in high yield with excellent enantioselectivity. 相似文献
20.
《Green Chemistry Letters and Reviews》2013,6(2):139-145
Abstract An efficient and mild protocol has been developed for the preparation of benzimidazoles, benzoxazoles, and benzothiazoles from reactions of aldehydes with o-substituted aminoaromatics in the presence of catalytic amount of Indion 190 resin. Short reaction time, ambient conditions, simple work-up procedure, high yield, easy availability, reusability, and use of an eco-friendly catalyst are some of the striking features of the present protocol. 相似文献