NEW MATERIAL: A (+)-cis compound, (-)-cis-enantiomer or (±)cis racemic modification of formula I [wherein R is a lower alkyl; R1 is pyridyl, phenyl which may have 1-3 substituents (NO2, OH, halogens, lower alkoxyls or lower alkanoyloxys), a group of any one of formulas II to VI or the like] and acid adducts thereof.

EXAMPLE: (±)-Cis-3-[(3,4-diemthoxybenzoyl)oxy]-2,3-dihydro[2-(dimethylamino) ethyl]-2-(4-methoxyphenyl)naphtho[1.2-b][1.4]thiazepin-4(5H)-one.

USE: A calcium antagonist useful for the inhibition or prevention of ischemia or hypertension or an inhibitor against the formation of lipid peroxides.

PREPARATION: A compound having the correspondign configuration and represented by formula VII is reacted with an acylating agent which imparts R1CD to obtain a compound of formula I.