Cyclohexyl amine derivatives and their use as tachykinin antagonists

A compound of formula (I), or a salt or prodrug thereof:

• ##STR9## wherein X represents O or S;
• R.sup.1 represents phenyl optionally substituted by 1, 2 or 3 groups selected from C.sub.1-6 alkyl, C.sub.2-6 alkenyl, C.sub.2-6 alkynyl, halo, cyano, nitro, trifluoromethyl, trimethylsilyl, --OR.sup.a, SR.sup.a, SOR.sup.a, SO.sub.2 R.sup.a, --NR.sup.a R.sup.b, --NR.sup.a COR.sup.b, --NR.sup.a CO.sub.2 R.sup.b, --CO.sub.2 R.sup.a or --CONR.sup.a R.sup.b ;
• R.sup.2 represents phenyl optionally substituted by C.sub.1-6 alkyl, C.sub.1-6 alkoxy, halo or trifluoromethyl;
• R.sup.3 and R.sup.4 each independently represent H, COR.sup.a, CO.sub.2 R.sup.a or C.sub.1-6 alkyl optionally substituted by a group selected from (CO.sub.2 R.sup.a, CONR.sup.a R.sup.b, hydroxy, cyano, COR.sup.a, NR.sup.a R.sup.b, and phenyl optionally substituted by C.sub.1-6 alkyl, C.sub.1-6 alkoxy, halo or trifluoromethyl);
• R.sup.5 represents H or XCH.sub.2 R.sup.6 wherein R.sup.6 represents phenyl optionally substituted by 1, 2 or 3 groups selected from C.sub.1-6 alkyl, C.sub.2-6 alkenyl, C.sub.2-6 alkynyl, halo, cyano, nitro, trifluoromethyl, trimethylsilyl, --OR.sup.a, SR.sup.a, SOR.sup.a, SO.sub.2 R.sup.a, --NR.sup.a R.sup.b, --NR.sup.a COR.sup.b, --NR.sup.a CO.sub.2 R.sup.b, --CO.sub.2 R.sup.a or --CONR.sup.a R.sup.b and X is as previously defined;
• R.sup.7 and R.sup.8 each independently represent H or C.sub.1-6 alkyl;
• and
• R.sup.a and R.sup.b each independently represent H, C.sub.1-6 alkyl, phenyl or trifluoromethyl
• with the exception of 2-amino-2-phenyl-1-benzyloxycyclohexane.