Compounds of the invention are useful in inhibiting thrombin and associated thrombotic occlusions having the following structure:or a pharmaceutically acceptable salt thereof, wherein Q is CH2, NR4, O, S, S(O) or S(O2), wherein R4 is H, C1-6 alkyl, aryl, or C3-8 cycloalkyl R1 is a heterocycle or —(CR5R6)1-2NH2, wherein R5 and R6, each time in which they occur, are independently H, C1-6 alkyl, —CH2F, —CHF2, CF3 or —CH2OH R2 is OH, NH2 or NHSO2CH3 R3 is C1-6 alkyl.
