The present invention concerns new heterocyclic compounds of the formula: ##SPC1## Wherein R.sub.1 and R.sub.2 are inter alia alkyl, chlorine or methoxy, R.sub.3 is hydroxy, alkylcarboxy or monoalkylcarbamoyloxy, and A is protected or unprotected carbonyl. The compounds possess analgesic and central nervous system depressant properties.