The invention relates to novel compounds of formula I where R1, R2, R3, R4, R5, R6, R7, R8, Q1, Q2 and Q3 are each as defined below. The compounds of formula I have antithrombotic activity and inhibit especially protease-activated receptor 1 (PAR1). The invention further relates to a process for preparing the compound of formula I and to the use thereof as a medicament.