PURPOSE: To provide a novel thieno[3,2-C]benzoxepin and naphtho[2,3- b]thiophene useful as an analgesic agent.

CONSTITUTION: This compd. is represented by formula I and formula II (R is lower alkyl, aryl lower alkyl; X, Y are each H, lower alkyl, halogen, lower alkoxy, CF3; W is CH2, CHOH, C=0; (n) is 1, 2), the optical isomer and pharmaceutically permissible salt thereof; for example, 7-fluoro-4-(1-methyl-4-piperidinyl)) thieno[3,2-C][1] benzoxepin-10(4H)-one. The compd. of the formula I is obtd. by treating the compd. of formula V obtd. by condensing the compd. of formula III with the compd. of formula IV (Hal is Cl, Br) with alkaline metal alkoxide in an etheric solvent.