Regioselective one pot synthesis of 2-alkyl/aryl-4<i>h</i>-benzo[1,4] thiazine-3-one<i>via</i>microwave irradiation
作者:Sukanta Kamila、Benjamin Koh、Omair Khan、Hongming Zhang、Edward R. Biehl
DOI:10.1002/jhet.5570430632
日期:2006.11
A series of 2-alkyl/aryl-4H-benzo[1,4]thiazine-3-ones have been synthesized by microwave irradiation of ethyl-2-bromo-2-alkyl/aryl acetate and 2-amino thiophenol in the presence of 1,8-diazabicyclo-[5.4.0] undec-7-ene and N-methylpiperidine. All compounds were characterized by 1H NMR, 13C NMR and elemental analyses, and by X-ray crystallography in the case of 2-methyl-4H-benzo[1,4]thiazin-3-one.
在存在下,通过微波辐射乙基-2-溴-2-烷基/乙酸芳基酯和2-氨基苯硫酚合成了一系列2-烷基/芳基-4 H-苯并[1,4]噻嗪-3-酮1,8-二氮杂双环-[5.4.0]十一烷基-7-烯和N-甲基哌啶。对于2-甲基-4 H-苯并[1,4]噻嗪-3-酮,所有化合物的特征在于1 H NMR,13 C NMR和元素分析,以及X射线晶体学。
[Omim][NO<sub>3</sub>], a Green and Base-Free Medium for One-Pot Synthesis of Benzothiazinones at Room Temperature
Abstract A general and efficient room-temperature procedure is developed for high-yield synthesis of 2H-benzo[b][1,4]thiazin-3(4H)-onederivatives in one pot from the reaction of 2-aminothiophenols with 2-bromoalkanoates in ionicliquid [bmim]NO3 without the use of any catalyst, base, or additive. Products were obtained in good yields by simple extraction with Et2O followed by evaporation of the volatile
A solvent-free procedure was developed for the reaction of 2-aminothiophenols with 2-bromoalkanoates, where KF-Al2O3 support and ball milling cooperatively lead to a green and efficient synthesis of several benzothiazinone derivatives in good to excellent yields. The catalyst could be recycled in further reactions while maintaining its activity. (C) 2015 Elsevier Ltd. All rights reserved.