Compounds of the invention, which may be useful in inhibiting thrombin and associated thrombotic occlusions, have the following structure: or a pharmaceutically acceptable salt thereof, wherein m is 0 or 1； R is a heterocycle, &mdash；(CR8R9)1-2NH2, or &mdash；(CR8R9)1-2OH, wherein R8 and R9, each time in which they occur, are independently H, C1-6 alkyl, &mdash；CH2F, &mdash；CHF2, CF3 or &mdash；CH2OH； W is a) &mdash；CHR1R2, where R1 is &mdash；C(CH3)3, and R2 is &mdash；(CH2)1-2OH, b) a 5- or 6-membered unsubstituted or substituted heterocycle having 1 or 2 heteroatoms selected from N and O, wherein substituted heterocycle is substituted with R3, c) a 9- or 10-membered unsubstituted or substituted heterocycle having 1 or 2 heteroatoms selected from N, O and S, wherein substituted heterocycle is mono-substituted with R3, or disubstituted with R3 and R4, or d) a 3-, 4-, or 5-membered carbocyclic ring which is unsubstituted, mono-substituted with R3, di-substituted with R3 and R4, or tri-substituted with R3, R4 and R5； R3 is &mdash；CF3, &mdash；COOH, &mdash；COOR7, &mdash；C(O)R6, &mdash；CH(OH)R6, &mdash；CH2R6, R6, =O, halogen, R7, &mdash；OH, &mdash；NH2, or &mdash；NHSO2R7； and R10 is H or C1-6 alkyl.
