2-Aminomethyleneindanone analgesic agents

A method of alleviating pain comprising the administration to a pain afflicted host of a pain alleviating effective amount of a compound of the formula:

• ##STR6## or a pharmaceutically-acceptable acid addition salt thereof, wherein R is hydrogen, lower alkyl or phenyl;
• ##STR7## wherein R.sub.3 and R.sub.4 are each hydrogen or lower alkyl, R.sub.5 and R.sub.6 are lower alkyl and n is integer of from 1 to 5;
• R.sub.1 and R.sub.2 are hydrogen lower alkyl;
• R.sub.7 and R.sub.8 are each hydrogen, fluoro or chloro;
• and R.sub.9 is hydrogen or fluoro.