Heterocyclic-NMDA antagonists

A compound of the formula:

• ##STR36## in which R.sub.1 is represented by hydrogen, C.sub.1-4 alkyl or CF.sub.3 ;
• M is represented by O, N--O--R.sub.4 or ##STR37## in which R.sub.4 is represented by hydrogen, C.sub.1-4 alkyl or phenyl (C.sub.1-3 alkyl);
• A is represented by:
• ##STR38## in which R.sub.2 is represented by hydrogen, C.sub.1-4 alkyl, cyclopentyl, cyclohexyl, ##STR39## phenyl, substituted phenyl in which the phenyl moiety is substituted with up to 3 substituents with each substituent being independently selected from the group consisting of halogens, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxyl, CF.sub.3, OCF.sub.3, OH, CN, COOR.sub.6 and CONR.sub.6 R.sub.7, phenyl (C.sub.1-3 alkyl) in which the phenyl moiety may be optionally substituted;
• R.sub.5 is represented by hydrogen, linear C.sub.1-4 alkyl, or phenyl (C.sub.1-3 alkyl);
• R' is represented by hydrogen, C.sub.1-4 alkyl, phenyl, phenyl (C.sub.1-3 alkyl), or cyclohexylmethyl;
• R.sub.6 and R.sub.7 are each represented by hydrogen or a C.sub.1 -C.sub.4 alkyl;
• in which n is represented by an integer from 2-4 and Alk and Alk.sub.1 are each represented by a C.sub.1-4 alkyl;
• or a pharmaceutically acceptable salt thereof.