The invention relates to compounds of formula (I), wherein R1 is hydrogen, lower alkyl or cycloalkyl R2 is hydrogen or R1 and R 2 may form together with the N and C atom to which they are attached a pyrrolidine ring optionally substituted by one or two F-atoms or by hydroxy, or may form an azetidine or a piperazine ring R3 is hydrogen, lower alkyl, lower alkyl substituted by hydroxy, -(CH2)2C(O)NH2, benzyl, phenyl, -CH2-five membered aromatic heterocyclic group, CH2-indolyl, -CH2-cycloalkyl, cycloalkyl or -(CH2)2-S-lower alkyl R3 is hydrogen or lower alkyl or X is -C(0)-CHR4-CHR4 -C(0)-NH-CH2- R4/R4 are hydrogen or one of R4 or R4 is amino: o is 0 or 1 or to pharmaceutically acceptable acid addition salt, to a racemic mixture or to its corresponding enantiomer and/or optical isomers thereof. It has been found that the present compounds are oxytocin receptor agonists for the treatment of autism, stress, including post traumatic stress disorder, anxiety, including anxiety disorders and depression, schizophrenia, psychiatric disorders and memory loss, alcohol withdrawel, drug addiction and for the treatment of Prader-Willi Syndrom.La présente invention concerne des composés de formule (I), dans laquelle R1 est hydrogène, alkyle inférieur ou cycloalkyle R2 est hydrogène ou R1 and R 2 peuvent former conjointement avec latome N et C auxquels ils sont liés un cycle pyrrolidine facultativement substitué par un ou deux atomes F ou par hydroxy, ou peuvent former un cycle azétidine ou pipérazine R3 est hydrogène, alkyle inférieur, alkyle inférieur substitué par hydroxy, -(CH2)2C(O)NH2, benzyle, phényle, -CH2-(groupe hétérocyclique aromatique à cinq chaînons), CH2-indolyle, -CH2-cycloalkyle, cycloalkyle ou -(CH2)2-S-(alkyle inférieur) R3 est hydrogène ou alkyle inférieur ou X est -C(O)-CHR4-CHR4 -C(O)-NH-CH2- R4/R4 sont hydrogène ou lun de R4 ou R4 est amino: o est 0 ou 1 ou un sel daddition dacide pharmaceutiquement acceptable, un mélange racémique ou son énantiomère co
