The present patent application discloses compounds having the formula ##STR1## or a pharmaceutically acceptable salt thereof wherein one R.sup.21 and R.sup.22 is alkyl and the other is hydrogen or both of R.sup.21 and R.sup.22 are hydrogen; and R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.11, R.sup.12, R.sup.13, and R.sup.14 each independently are hydrogen, halogen, CF.sub.3, CN, or NO.sub.2 ; provided that at least one of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.11, R.sup.12, R.sup.13, and R.sup.14 are different from hydrogen The compounds are useful as in vivo active glutamate antagonists.