NEW MATERIAL:A compound expressed by formula I (R1 is H or lower alkoxyl; R2 is lower alkyl, phenyl or phenyl substituted by a lower alkyl or nitro; R3 is lower alkylaminoalkyl or morpholino lower alkyl).

EXAMPLE: 2-( 4-Methoxyphenyl )-3-( 4-chlorobenzenesulfonyloxy )-5-(2-dimethylaminoethyl)-1,5-benzothiazepin-4(5H)-one.

USE: Medicines having low toxicity and pharmacological action such as central nervous system regulating action, coronary vasodilator action, antiarrhythmic action, local anesthetic action, analgesic action, anti-inflammatory action and diuretic action.

PREPARATION: A novel 2-phenyl- or 2-(substituted phenyl)-2,3-dihydro-5-substituted-1,5-benzothiazepine-3,4(5H)-dione expressed by formula II or an acid addition salt thereof is reacted with a substituted sulfonyl halide to afford the aimed compound expressed by formula I .