Stereoselective synthesis of 2-acyl-3,4-dihydro-1,4-benzothiazines.
作者:Saverio Florio、Erbana Epifani、Ludovico Ronzini、Giovanna Gasparri Fava、Giorgio Pelosi、Vittorio Lucchini
DOI:10.1016/s0040-4020(01)90415-6
日期:1994.4
2-Benzylidene-4-methyl-3-oxo-2H-1,4-benzothiazine 2 undergoes 1,2-addition with MeMgI and allylic magnesium halides to give 2-acyl-4-methyl-3-phenyl-3,4-dihydro-2H-1,4-benzothiazines 3a-d. Lithiation of 3a and subsequent reaction with Mel and PhCH(2)Br leads to compounds 3e, 3f, 3h and 3i. In contrast, the reaction of lithiated 3a with benzaldehyde and 2,6-dichlorobenzaldehyde furnished compounds 3k and 31 respectively.