Azetidinones of formula (I) [R=OH, alkoxy, aralkoxy, NR5R6 (R5,R6=H, alkyl, hydroalkyl, alkoxyalkyl, cycloalkyl, aryl, aminoalkyl, acyloxyalkyl; NR5N6=5-or 6-membered ring which may contain O, S or another N); R1,R3,R4=H, alkyl; R2=(un)substd. imidazoyl; n=0-30 x=CH2, CH2CH2, O,S! were prepd. Thus, H-His-ProNH2.2HBr(II.HBr) was treated with Et3N in DMF to yield II, which was coupled with (S)-2- azetidinone-4-carboxylic acid(III) by DCC/1-hydroxybenzotriazole in DMF to give IV. (I) have CNS activity stronger than thyrotopin- releasing hormone and are useful for improving disturbance of conciousness in schizophrenia etc.
PROCESS FOR PREPARING 4-SUBSTITUTED-2-AZETIDINONE COMPOUNDS