PURPOSE: To prepare a new heterocyclic compd. effective for a wide range of diseases caused by the excess of tachykinin, particularly of P substance such as troubles in the central nervous system, nerve degenerative troubles or the like and useful as tachykinin antagonists.

CONSTITUTION: The compd. of formula I [Q is phenyl halide, naphthyl, indolyl, benzthiophene, benzofuranyl, benzyl or the like; R1 is H, an alkyl or alkenyl; R2 is an alkyl, alkenyl, alkinyl or the like; Z is O, S or NR8 (R8 is H, an alkyl, phenyl or the like), etc.] or the salt or prodrug thereof such as 3-(3,5-bistri- fluoromethylbenzyl)-5-(indole-3-ylmethylene)oxazolidine. The compd. in which Z is O, S or NR8 among the compds. of the formula I is obtd. by reacting an intermediate of formula II with phosgene or the body eqivalent to phosgene (such as carbonylimidazole).