3,4-dihydro-2-(2-hydroxy-5-methoxyphenyl)-4-methyl-2-methylthio-3-oxo-2H-1,4-benzothiazine 、 beta-Chloropropionaldehyde diethyl acetate 、
N-methyl-2-(3,4-dimethoxyphenyl)propylamine hydrochloride 以to give 4.7 g (64.9%) of 2-[2-(3,3-diethoxypropoxy)-5-methoxyphenyl]-3,4-dihydro-4-methyl-2-methylthio-3-oxo-2H-1,4-benzothiazine (compound No. 21, (IR: neat, cm-1) 1660, 1555, 1048, 750), 2.8 g (72.0%) of 3,4-dihydro-2-[5-methoxy-2-(3-oxopropoxy)phenyl]-4-methyl-2-methylthio-3-oxo-2H-1,4-benzothiazine (compound No. 22, (IR: neat, cm-1) 1722, 1658, 1588, 1036, 748) and 0.6 g (12.8%) of the titled compound (mp. 153°-156.5° C. (dec.))的产率得到2-[2-(3,3-diethoxypropoxy)-5-methoxyphenyl]-3,4-dihydro-4-methyl-2-methylthio-3-oxo-2H-1,4-benzothiazine