Compounds of the formula I in which R1, X and Y have the meanings indicated in Claim 1, are inhibitors of Tankyrase, and can be employed, inter alia, for the treatment of diseases such as cancer, cardiovascular diseases, central nervous system injury and different forms of inflammation.本發明提供式I化合物其中R1、X及Y具有如技術方案1中指示之意義,該等化合物為端錨聚合酶(Tankyrase)之抑制劑,且尤其可用於治療疾病,諸如癌症、心血管疾病、中樞神經系統損傷及不同形式發炎。