Mitotic kinesin inhibitors

1. The compound of the formula II:

or a pharmaceutically acceptable salt or stereoisomer thereof, wherein

one of X and Y is N and the other of X and Y is CH;

a is 0 or 1;

b is 0 or 1;

p is 0 to 3;

r is 0 or 1;

s is 0 or 1;

R 2 is selected from:

1) hydrogen,

2) C 1 -C 10 alkyl,

said alkyl is optionally substituted with one or more substituents selected from R 5 ;

R 3 is independently selected from:

1) (C═O) a O b C 1 -C 10 alkyl,

2) (C═O) a O b aryl,

3) halo,

4) OH,

5) O b C 1 -C 6 perfluoroalkyl,

6) (C═O) a NR 6 R 7 ,

7) CN,

8) (C═O) a O b C 3 -C 9 cycloalkyl,

9) (C═O) a O b heterocyclyl,

10) SO 2 NR 6 R 7 , and

11) SO 2 C 1 -C 10 alkyl,

said alkyl, aryl, cycloalkyl, and heterocyclyl is optionally substituted with one or more substituents selected from R 5 ;

R 4 is independently selected from:

1) H;

2) (C═O) a O b C 1 -C 10 alkyl,

3) (C═O) a O b aryl,

4) halo,

5) OH,

6) O b C 1 -C 6 perfluoroalkyl,

7) O a (C═O) b NR 6 R 7 ,

8) (C═O) a O b C 3 -C 8 cycloalkyl,

9) SO 2 C 1 -C 10 alkyl, and

10) SO 2 NR 6 R 7 ,

said alkyl, aryl and cycloalkyl optionally substituted with one or more substituents selected from R 5 ;

R 5 is selected from:

1) (C═O) r O s (C 1 -C 10 )alkyl,

2) O r (C 1 -C 3 )perfluoroalkyl,

3) (C 0 -C 6 )alkylene-S(O) m R a ,

4) oxo,

5) OH,

6) halo,

7) CN,

8) (C═O) r O s (C 2 -C 10 )alkenyl,

9) (C═O) r O s (C 2 -C 10 )alkynyl,

10) (C═O) r O s (C 3 -C 6 )cycloalkyl,

11) (C═O) r O s (C 0 -C 6 )alkylene-aryl,

12) (C═O) r O s (C 0 -C 6 )alkylene-heterocyclyl,

13) (C═O) r O s (C 0 -C 6 )alkylene-N(R b ) 2 ,

14) C(O)R a ,

15) (C 0 -C 6 )alkylene-CO 2 R a ,

16) C(O)H,

17) (C 0 -C 6 )alkylene-CO 2 H, and

18) C(O)N(R b ) 2 ,

said alkyl, alkenyl, alkynyl, cycloalkyl, aryl, and heterocyclyl is optionally substituted with up to three substituents selected from R b , OH, (C 1 -C 6 )alkoxy, halogen, CO 2 H, CN, O(C═O)C 1 -C 6 alkyl, oxo, and N(R b ) 2 ;

R 6 and R 7 are independently selected from:

1) H,

2) (C═O)O b C 1 -C 10 alkyl,

3) (C═O)O b C 3 -C 8 cycloalkyl,

4) (C═O)O b aryl,

5) (C═O)O b heterocyclyl,

6) C 1 -C 10 alkyl,

7) aryl,

8) C 2 -C 10 alkenyl,

9) C 2 -C 10 alkynyl,

10) heterocyclyl,

11) C 3 -C 8 cycloalkyl,

12) SO 2 R a , and

13) (C═O)NR b 2 ,

said alkyl, cycloalkyl, aryl, heterocylyl, alkenyl, and alkynyl is optionally substituted with one or more substituents selected from R 5 , or

R 6 and R 7 can be taken together with the nitrogen to which they are attached to form a monocyclic or bicyclic heterocycle with 4-7 members in each ring and optionally containing, in addition to the nitrogen, one or two additional heteroatoms selected from N, O and S, said monocyclic or bicyclic heterocycle optionally substituted with one or more substituents selected from R 5 ;

R a is (C 1 -C 6 )alkyl, (C 3 -C 6 )cycloalkyl, aryl, or heterocyclyl; and

R b is H, (C 1 -C 6 )alkyl, (C 1 -C 6 )alkyl-NR a 2 , (C 1 -C 6 )alkyl-NH 2 , (C 1 -C 6 )alkyl-NHR a , aryl, heterocyclyl, (C 3 -C 6 )cycloalkyl, (C═O)OC 1 -C 6 alkyl, (C═O)C 1 -C 6 alkyl or S(O) 2 R a .

2. A compound which is:

N-(3-amino-2-(R,S)-fluoropropyl)-N-[1-(3-benzyl-4-oxo-3,4-dihydropyrido[3,4-d]pyrimidin-2-yl)-2-(R,S)-methylpropyl]-4-methylbenzamide

or a pharmaceutically acceptable salt thereof.

3. A pharmaceutical composition that is comprised of a compound in accordance with claim 1 and a pharmaceutically acceptable carrier.

4. A pharmaceutical composition that is comprised of a compound in accordance with claim 2 and a pharmaceutically acceptable carrier.