从适当取代的异噻唑二胺合成了新的咪唑并[4,5- d ]异噻唑环系的几种衍生物。3-甲基-4,5-二氨基异噻唑(4a)与二乙氧基乙酸甲酯的反应产生了低产率的3-甲基咪唑并[4,5- d ]异噻唑(5a)。然而,4,5-二氨基异噻唑(4b)与二乙氧基甲基乙酸酯的类似反应未能产生母体咪唑并[4,5- d ]异噻唑环系统。二胺4a和4b易于与硫代羰基二咪唑环合,得到不稳定的硫酮6a和6b,它们被烷基化了原位得到相应的5-甲基硫代咪唑并[4,5- d ]异噻唑7a和7b的良好产率。通过用阮内镍处理,这些化合物都不能还原为相应的5-未取代的衍生物。据我们所知,这是咪唑并[4,5- d ]异噻唑环系统的首次报道。
从适当取代的异噻唑二胺合成了新的咪唑并[4,5- d ]异噻唑环系的几种衍生物。3-甲基-4,5-二氨基异噻唑(4a)与二乙氧基乙酸甲酯的反应产生了低产率的3-甲基咪唑并[4,5- d ]异噻唑(5a)。然而,4,5-二氨基异噻唑(4b)与二乙氧基甲基乙酸酯的类似反应未能产生母体咪唑并[4,5- d ]异噻唑环系统。二胺4a和4b易于与硫代羰基二咪唑环合,得到不稳定的硫酮6a和6b,它们被烷基化了原位得到相应的5-甲基硫代咪唑并[4,5- d ]异噻唑7a和7b的良好产率。通过用阮内镍处理,这些化合物都不能还原为相应的5-未取代的衍生物。据我们所知,这是咪唑并[4,5- d ]异噻唑环系统的首次报道。
The Synthesis of Substituted Imidazo[4,5-d]isothiazoles via the Ring Annulation of Isothiazole Diamines: An Investigation of the Chemical, Physical, and Biological Properties of Several Novel 5:5 Fused Analogs of the Purine Ring System
作者:Eric E. Swayze、Leroy B. Townsend
DOI:10.1021/jo00125a016
日期:1995.10
A series of imidazo[4,5-d]isothiazoles have been prepared from isothiazole precursors via a strategy employing ring annulation of the appropriate isothiazole diamine. In this manner, several 4,5-diaminoisothiazoles were converted into the corresponding 5-(alkylthio)imidazo[4,5-d]isothiazoles via a two-step, one-pot procedure in good yield. This methodology proved quite general and allows for the introduction of various substituents onto the 3-, 5-, and 6-positions of this ring system. Reaction with Raney nickel destroyed the ring system, presumably through removal of the sulfur at the 1-position, and the 5-mercapto substituent could not be removed selectively. Ring annulation with diethoxymethyl acetate provided the 5-unsubstituted imidazo[4,5-d]isothiazoles but was less general, and only the 3-methyl derivatives could be prepared. Imidazo[4,5-d]isothiazoles bearing no substituents on nitrogen readily underwent alkylation to afford mixtures of the N-4- and N-6-substituted compounds. The chemical and physical properties of these novel heterocycles were studied in detail, and the structure of 3-methyl-5-methanesulfonyl-6-(phenylmethyl)imidazo[4,5-d] isothiazole was verified by single crystal X-ray diffraction studies.