Synthesis of 1,2-benzisothiazoles by the oxidative ring contraction of 2-aryl- and 4-aryl-3,4-dihydro-2H-1,3-benzothiazines
作者:János Szabó、Erzsébet Szűcs、Lajos Fodor、Gábor Bernáth、Pál Sohár
DOI:10.1016/s0040-4020(01)80102-2
日期:1989.1
4-aryl isomers of the latter (11a, b) furnished 2-substituted 1,2-benzisothiazolidine 1-oxides (7a-c) and their 3-aryl analogues (12a, b), respectively. The observed conversions of the 1,3-benzothiazines to 1,2-benzisothiazole and to 1,2-benzisothiazolidines are new ring transformation reactions of 3,4-dihydro-1,3-benzothiazines, representing a new route for the synthesis of 1,2-benzisothiazoles and
6,7-二甲氧基-2-芳基-3,4-二氢-2H-1,3-苯并噻嗪(1a-e)的高碘酸钠氧化得到5,6-二甲氧基-1,2-苯并噻唑(4)。N-取代的类似物(6a-c)和后者的4-芳基异构体(11a,b)提供了2-取代的1,2-苯并噻唑烷1-氧化物(7a-c)及其3-芳基类似物(12a, b)分别。观察到的1,3-苯并噻嗪向1,2-苯并噻唑并向1,2-苯并噻唑烷的转化是3,4-二氢-1,3-苯并噻嗪的新环转化反应,代表了1的合成新途径,2-苯并噻唑及其氢化衍生物。