Iminium carbonic acid derivative salts.<b>IX</b>. Synthesis of<i>N,S</i>-containing heterobicycles from<i>N</i>-protected 2-methylthio-1,3-thiazinium and 2-methylthiothiazolium salts part 1. Preparation of<i>N</i>-protected 2-methylthio-1,3-thiazinium and 2-methylthiothiazolium salts and their reaction with CH-acidic compounds
by methyl iodide or trimethyloxonium tetrafluoroborate. This activated species were reacted with CH-acidic compounds forming ketene-N,S-acetals. The protection group was removed with trifluoracetic acid to yield the N-unsubstituted ketene-N,S-acetals.
N -Boc保护的1,3-噻嗪-2-硫酮和噻唑烷-2-硫酮通过甲基碘或四氟硼酸三甲基氧鎓转化为相应的2-甲硫基-1,3-噻嗪鎓盐和2-甲基硫代噻唑鎓盐。该活化的物质与CH-酸性化合物反应形成烯酮-N,S-乙缩醛。用三氟乙酸除去保护基,得到N-未取代的烯酮-N,S-乙缩醛。