The present invention relates to compounds of formula I wherein R1, L, R2, R3, R4, and Y are as defined in the specification, or to a pharmaceutically acceptable salt or acid addition salt, to a racemic mixture, or to its corresponding enantiomer and/or optical isomer and/or stereoisomers thereof.The compounds may be used for the treatment of Parkinson’s disease, anxiety, emesis, obsessive compulsive disorder, autism, neuroprotection, cancer, depression and diabetes type 2.本發明係關於式I化合物其中R1、L、R2、R3、R4及Y係如說明書中所定義，或其醫藥上可接受的鹽或酸加成鹽、外消旋混合物或其相應的對映異構體及/或光學異構體及/或立體異構體。該等化合物可用於治療帕金森氏病(Parkinson's disease)、焦慮、嘔吐、強迫症、自閉症、神經保護、癌症、抑鬱及2型糖尿病。
