The present invention provides for compounds of formula (I): wherein R1-R4 and n are defined herein. The present invention also provides for pharmaceutical compositions and combinations comprising a compound of formula (I) as well as for the use of such compounds as tankyrase inhibitors and in the treatment of Wnt signaling and tankyrase 1 and 2 signaling related disorders which include, but are not limited to, cancer.本発明は、式(I)の化合物を提供する。本発明はまた、式(I)の化合物を含む医薬組成物及び組合せ並びにタンキラーゼ阻害剤としての、また、癌を含むが、これに限定されないWntシグナル伝達並びにタンキラーゼ1及び2シグナル伝達関連障害の治療におけるそのような化合物の使用を提供する。