One-Pot Syntheses of 2-(2-Sulfanyl-4H-3,1-benzothiazin-4-yl) acetic Acid Derivatives via Reactions of 3-(2-Isothiocyanatophenyl)prop-2-enoic Acid Derivatives with Thiols or Sodium Sulfide
One-Pot Syntheses of 2-(2-Sulfanyl-4H-3,1-benzothiazin-4-yl) acetic Acid Derivatives via Reactions of 3-(2-Isothiocyanatophenyl)prop-2-enoic Acid Derivatives with Thiols or Sodium Sulfide
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DOI：
10.1002/hlca.201000340
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发表时间：
2011-01-01
影响因子：
1.8
通讯作者：
Kobayashi, Kazuhiro
中科院分区：
文献类型：
--
作者：
Fukamachi, Shuhei;Konishi, Hisatoshi;Kobayashi, Kazuhiro
本文报道了两种在温和条件下合成2-（2-硫烷基-4H-3，1-苯并噻嗪-4-基）乙酸衍生物3的有效方法。第一种方法是基于3（2-异硫氰酸根合苯基）丙-2-烯酸酯1a - 1c与硫醇在Et（3）N存在下在THF中于室温下反应，得到相应的二硫代氨基甲酸酯中间体2，其在相同温度下通过S-原子攻击1中的丙-2-烯酰基部分而进行自发环化，4-加成方式（Michael加成），在一锅中得到2-（2-硫烷基-4H-3，1-苯并噻嗪-4-基）乙酸酯。第二种方法涉及用Na（2）S处理3-（2-异硫氰酸根合苯基）丙-2-烯酸衍生物1b - 1d，通过类似的加成/环化顺序形成2-（2-钠硫基-4H-3，1-苯并噻嗪-4-基）乙酸中间体5，然后使其与烷基或芳基卤化物反应，得到衍生物3。省略卤化物的加入，可以得到2-（2-硫代-4H-3，1-苯并噻嗪-4-基）乙酸衍生物6。
Two efficient methods for the preparation of 2-(2-sulfanyl-4H-3,1-benzothiazin-4-yl) acetic acid derivatives 3 under mild conditions have been developed. The first method is based on the reaction of 3( 2-isothiocyanatophenyl) prop-2-enoates 1a - 1c with thiols in the presence of Et(3)N in THF at room temperature, leading to the corresponding dithiocarbamate intermediates 2, which underwent spontaneous cyclization at the same temperature by an attack of the S-atom at the prop-2-enoyl moiety in a 1,4-addition manner (Michael addition) to give 2-(2-sulfanyl-4H-3,1-benzothiazin-4-yl)acetates in one pot. The second method involves treatment of 3-(2-isothiocyanatophenyl)prop-2-enoic acid derivatives 1b - 1d with Na(2)S leading to the formation of 2-(2-sodiosulfanyl-4H-3,1-benzothiazin-4-yl)acetic acid intermediates 5 by a similar addition/cyclization sequence, which are then allowed to react with alkyl or aryl halides to afford derivatives 3. 2-(2-Thioxo-4H-3,1-benzothiazin-4-yl)acetic acid derivatives 6 can be obtained by omitting the addition of halides.