Abstract: Phenyl-2-pyrrolidinones of the formula ##SPC1##Wherein R is a halogen or trifluoromethyl, R.sub.1 is lower alkyl, lower alkenyl, lower alkynyl, phenyl or halogen-substituted phenyl, R.sub.2 is hydrogen, lower alkyl or phenyl and R.sub.3 is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, cyclopentyl or benzyl, as well as the cis and trans diastereoisomers thereof, are active on the central nervous system. In particular they have valuable anxiolytic and antidepressive properties. Processes for their preparation are given.

Abstract: A process for the preparation of 2H-3-isoquinolones having the formula ##SPC1##Wherein R.sub.1 and R.sub.2 are each hydrogen, halogen, lower alkyl, lower alkoxy, aryl, haloaryl, alkylaryl or alkoxyaryl; R.sub.3 and R.sub.4 are each hydrogen, lower alkyl, lower alkoxyalkyl, lower alkenyl, lower alkynyl, cycloalkyl, aryl, aralkyl, or halo-aralkyl, which comprises cyclizing an N-formyl-2-phenyl-acetamide of the formula ##SPC2##Wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 have the same meaning as above, with a cyclodehydration agent. Said 2H-3-isoquinolones are useful as starting materials e.g. in the synthesis of 1,4-dihydro-1,4-etheno-isoquinolin-3(2H)-ones which are valuable chemotherapeutic agents in the treatment of disorders of the central nervous system, such as troubles of wakefulness, disorders of equilibrium and vertigo.