作者:Thierry Besson、Jérôme Guillard、Charles W. Rees、Valérie Thiéry
DOI:10.1039/a707801c
日期:——
cleaved by ethylmagnesium bromide in hot THF to give the corresponding isothiocyanates. The transformation 2→6→ArNCS can be performed as a ‘one-pot’ operation. The imines 2 are also converted, more slowly, into the isothiocyanates by sodium hydride in hot THF, via the cyanothioformanilides 6. Conversion of the anilides 6 into isothiocyanates is much faster under microwave irradiation in 2,6-lutidine. Mechanisms
A new, direct synthesis is described for the relatively rare but synthetically very versatile quinazoline-2-carbonitriles from antranilonitriles and 4,5-dichloro-1,2,3-dithiazolium chloride 1. Treatment of iminodithiazole 6, from 4,5-dimethoxyanthranilonitrile and the salt 1, with alcohols and a base gives 4-alkoxyquinazoline-2-carbonitriles 8 in good yield. Treatment of the parent iminodithiazole
描述了一种新的直接合成方法,该方法可从苯甲腈和4,5-二氯-1,2,3-二噻唑鎓1中相对稀少但合成用途非常广泛的喹唑啉-2-腈进行处理。由4,5-二甲氧基蒽腈处理亚氨基二噻唑6,盐1与醇和碱一起以良好的收率得到4-烷氧基喹唑啉-2-腈8。用醇和氢化钠处理母体亚氨基二噻唑2(R = H; X = CN)得到较低产率的类似喹唑啉12,尽管这些产率大大提高并且在微波辐射下缩短了反应时间。或者,可以将亚胺6转化为更具反应性的氰基硫代甲酰胺7,其在醇中短暂加热后,以高收率得到相同的喹唑啉8。
New syntheses of aryl isothiocyanates from N-arylimino-1,2,3-dithiazoles
作者:Thierry Besson、Jérôme Guillard、Charles W. Rees、Michel Thérisod
DOI:10.1039/a700551b
日期:——
Treatment of N-arylimino-1,2,3-dithiazoles 2 with
ethylmagnesium bromide (2 equiv.) gives the corresponding aryl
isothiocyanates 13, providing a very mild two-step conversion of
ArNH
2
into ArNCS avoiding hazardous reagents; alternatively the
iminodithiazoles 2 can be converted into cyanothioformanilides 11 which
rapidly give the same isothiocyanates with 1 equiv. of the Grignard
reagent.
Expeditious routes to 4-alkoxyquinazoline-2-carbonitriles and thiocarbamates via N-arylimino-1,2,3-dithiazoles using microwave irradiation
作者:Thierry Besson、Marie-Joëlle Dozias、Jérôme Guillard、Patrick Jacquault、Marie-Dominique Legoy、Charles W. Rees
DOI:10.1016/s0040-4020(98)00276-2
日期:1998.6
Conversion of N-arylimino-4-chloro-5H-1,2,3-dithiazole 11 into the 4-alkoxyquinazoline-2-carbonitriles 13a-i and of the aryl isothiocyanates 15 into aryl thiocarbamates 16a-j with sodium alkoxides in the corresponding alcohol, either by conventional thermolysis or by microwave irradiation are described and directly compared. Microwave irradiation of the solutions in open vessels in a monomode system with focused irradiation and continuous temperature control (Synthewave S402 reactor) usually gave cleaner, faster and higher yielding reactions. These reactions could be safely and beneficially scaled up to multigram quantities in a larger reactor (Synthewave S1000). (C) 1998 Elsevier Science Ltd. All rights reserved.
Besson, Thierry; Emayan, Kumaraswamy; Rees, Charles W., Journal of the Chemical Society. Perkin transactions I, 1995, # 17, p. 2097 - 2102
作者:Besson, Thierry、Emayan, Kumaraswamy、Rees, Charles W.