The invention relates to the use of a compound of formula I wherein A1 is phenyl or a five or six membered hereroaryl group, containing 1, 2 or 3 heteroatoms, selected from N or S; R1 is hydrogen, lower alkyl, halogen, lower alkyl substituted by halogen or cycloalkyl; A2 is phenyl; R2 is halogen, lower alkyl, lower alkyl substituted by halogen, lower alkoxy substituted by halogen, cyano, S-lower alkyl substituted by halogen, S(O)2-lower alkyl substituted by halogen; n is 1 or 2; or a pharmaceutically acceptable acid addition salt, or a racemic mixture or its corresponding enantiomer and/or optical isomers thereof, for the treatment of autism, stress, including post traumatic stress disorder, anxiety, including anxiety disorders and depression, schizophrenia, psychiatric disorders and memory loss, alcohol withdrawal, drug addiction and for the treatment of Prader-Willi Syndrome.