Compounds and methods for inhibiting mitotic progression

Abstract

This invention relates to compounds and methods for the treatment of cancer. In particular, the invention provides compounds that inhibit Aurora kinase, pharmaceutical compositions comprising the compounds, and methods of using the compounds for the treatment of cancer.

1 . A compound of formula (A):  
       
         
           
           
               
               
           
         
       
       or a pharmaceutically acceptable salt thereof;  
       wherein: 
 R f1  is hydrogen, or R f1  and R f2  together form a bond;  
 R f2  is hydrogen, or R f2  forms a bond with either R f1  or R x ;  
 each of R x  and R y  independently is hydrogen, fluoro, or an optionally substituted C 1-6  aliphatic; or R x  and R y , taken together with the carbon atom to which they are attached, form an optionally substituted 3- to 6-membered cycloaliphatic ring; or R x  and R f2  together form a bond;  
 G is hydrogen, an optionally substituted aliphatic or Ring B when R f1  is hydrogen; and G is hydrogen, —OR 5 , —N(R 4 ) 2 , —SR 5 , an optionally substituted aliphatic, or Ring B when R f1  and R f2  together form a bond;  
 Ring A is a substituted or unsubstituted 5- or 6-membered aryl, heteroaryl, cycloaliphatic, or heterocyclyl ring;  
 Ring B is a substituted or unsubstituted aryl, heteroaryl, heterocyclyl, or cycloaliphatic ring;  
 Ring C is a substituted or unsubstituted aryl, heteroaryl, heterocyclyl, or cycloaliphatic ring;  
 R a  is hydrogen, —C(O)R 1 , —CO 2 R 1 , —SO 2 R 1 , or a C 1-3  aliphatic having 0-2 substituents independently selected from R 3  or R 7 ;  
 R e  is hydrogen, —OR 5 , —N(R 4 ) 2 , —SR 5 , —NR 4 C(O)R 5 , —NR 4 C(O)N(R 4 ) 2 , —NR 4 CO 2 R 6 , —N(R 4 )SO 2 R 6 , —N(R 4 )SO 2 N(R 4 ) 2 , or a C 1-3  aliphatic optionally substituted with R 3  or R 7 ;  
 R 1  is C 1-6  aliphatic or an optionally substituted aryl, heteroaryl, or heterocyclyl group;  
 each R 1  independently is selected from the group consisting of -halo, —OH, —O(C 1-3  alkyl), —CN, —N(R 4 ) 2 , —C(O)(C 1-3  alkyl), —CO 2 H, —CO 2 (C 1-3  alkyl), —C(O)NH 2 , and —C(O)NH(C 1-3  alkyl);  
 each R 4  independently is hydrogen or an optionally substituted aliphatic, aryl, heteroaryl, or heterocyclyl group; or two R 4  on the same nitrogen atom, taken together with the nitrogen atom, form an optionally substituted 5- to 6-membered heteroaryl or 4- to 8-membered heterocyclyl ring having, in addition to the nitrogen atom, 0-2 ring heteroatoms selected from N, O, and S;  
 each R 5  independently is hydrogen or an optionally substituted aliphatic, aryl, heteroaryl, or heterocyclyl group;  
 each R 6  independently is an optionally substituted aliphatic or aryl group; and  
 each R 7  independently is an optionally substituted aryl, heterocyclyl, or heteroaryl group.  
 
     
     
         2 . The compound of  claim 1 , having formula (A-1):  
       
         
           
           
               
               
           
         
       
       or a pharmaceutically acceptable salt thereof;  
       wherein: 
 Ring A is a substituted or unsubstituted 5- or 6-membered aryl, heteroaryl, cycloaliphatic, or heterocyclyl ring;  
 Ring B is a substituted or unsubstituted aryl, heteroaryl, cycloaliphatic, or heterocyclyl ring;  
 Ring C is a substituted or unsubstituted aryl, heteroaryl, heterocyclyl, or cycloaliphatic ring;  
 R e  is hydrogen, —OR 5 , —N(R 4 ) 2 , —SR 5 , or a C 1-3  aliphatic optionally substituted with R 3  or R 7 ;  
 each of R x  and R y  independently is hydrogen, fluoro, or an optionally substituted C 1-6  aliphatic; or R x  and R y , taken together with the carbon atom to which they are attached, form an optionally substituted 3- to 6-membered cycloaliphatic ring;  
 each R 3  independently is selected from the group consisting of -halo, —OH, —O(C 1-3  alkyl), —CN, —N(R 4 ) 2 , —C(O)(C 1-3  alkyl), —CO 2 H, —CO 2 (C 1-3  alkyl), —C(O)NH 2 , and —C(O)NH(C 1-3  alkyl);  
 each R 4  independently is hydrogen or an optionally substituted aliphatic, aryl, heteroaryl, or heterocyclyl group; or two R 4  on the same nitrogen atom, taken together with the nitrogen atom, form an optionally substituted 5- to 6-membered heteroaryl or 4- to 8-membered heterocyclyl ring having, in addition to the nitrogen atom, 0-2 ring heteroatoms selected from N, O, and S;  
 each R 5  independently is hydrogen or an optionally substituted aliphatic, aryl, heteroaryl, or heterocyclyl group; and  
 each R 7  independently is an optionally substituted aryl, heterocyclyl, or heteroaryl group.  
 
     
     
         3 . The compound of  claim 2 , having formula (C):  
       
         
           
           
               
               
           
         
       
       or a pharmaceutically acceptable salt thereof, wherein: 
 Ring B is substituted with 0-2 independently selected R c  and 0-3 independently selected R 2c  or C 1-6  aliphatic groups;  
 each R c  independently is selected from the group consisting of C 1-6  aliphatic, R 2c , R 7c , —T 1 —R 2c , and —T 1 —R 7c ;  
 T 1  is a C 1-6  alkylene chain optionally substituted with R 3  or R 3b , wherein T 1  or a portion thereof optionally forms part of a 3- to 7-membered ring;  
 R 2c  is -halo, —NO 2 , —CN, —C(R 5 )═C(R 5 ) 2 , —C(R 5 )═C(R 5 )(R 10 ), —C≡C—R 5 , —C≡C—R 10 , —OR 5 , —SR 6 , —S(O)R 6 , —SO 2 R 6 , —SO 2 N(R 4 ) 2 , —N(R 4 ) 2 , —NR 4 C(O)R 5 , —NR 4 C(O)N(R 4 ) 2 , —NR 4 CO 2 R 6 , —O—CO 2 R 5 , —OC(O)N(R 4 ) 2 , —O—C(O)R 5 , —CO 2 R 5 , —C(O)—C(O)R 5 , —C(O)R 5 , —C(O)N(R 4 ) 2 , —C(═NR 4 )—N(R 4 ) 2 , —C(═NR 4 )—OR 5 , —N(R 4 )—N(R 4 ) 2 , —N(R 4 ) C(═NR 4 )—N(R 4 ) 2 , —N(R 4 )SO 2 R 6 , —N(R 4 )SO 2 N(R 4 ) 2 , —P(O)(R 5 ) 2 , or —P(O)(OR 5 ) 2 ;  
 each R 7c  independently is an optionally substituted aryl, heterocyclyl, or heteroaryl group;  
 Ring C is substituted with 0-2 independently selected R d  and 0-3 independently selected R 2d  or C 1-6  aliphatic groups;  
 each R d  independently is selected from the group consisting of C 1-6  aliphatic, R 2d , R 7d , —T 1 —R 2d , —T 2 —R 7d , —V—T 3 —R 2d , and —V—T 3 —R 7d ;  
 T 2  is a C 1-6  alkylene chain optionally substituted with R 3  or R 3b , wherein the alkylene chain optionally is interrupted by —C(R 5 )═C(R 5 )—, —C≡C—, —O—, —O—, —S—, —S(O)—, —S(O) 2 —, —SO 2 N(R 4 )—, —N(R 4 )—, —N(R 4 )C(O)—, —NR 4 C(O)N(R 4 )—, —N(R 4 )CO 2 —, —C(O)N(R 4 )—, —C(O)—, —C(O)—C(O)—, —CO 2 —, —OC(O)—, —OC(O)O—, —OC(O)N(R 4 )—, —N(R 4 )—N(R 4 )—, —N(R 4 )SO 2 —, or —SO 2 N(R 4 )—, and wherein T 2  or a portion thereof optionally forms part of a 3-7 membered ring;  
 T 3  is a C 1-6  alkylene chain optionally substituted with R 3  or R 3b , wherein the alkylene chain optionally is interrupted by —C(R 5 )═C(R 5 )—, —C≡C—, —O—, —S—, —S(O)—, —S(O) 2 —, —SO 2 N(R 4 )—, —N(R 4 )—, —N(R 4 )C(O)—, —NR 4 C(O)N(R 4 )—, —N(R 4 )CO  2 —, —C(O)N(R 4 )—, —C(O)—, —C(O)—C(O)—, —CO 2 —, —OC(O)—, —OC(O)O—, —OC(O)N(R 4 )—, —N(R 4 )—N(R 4 )—, —N(R 4 )SO 2 —, or —SO 2 N(R 4 )—, and wherein T 3  or a portion thereof optionally forms part of a 3-7 membered ring;  
 V is —C(R 5 )═C(R 5 )—, —C≡C—, —O—, —S—, —S(O)—, —S(O) 2 —, —SO 2 N(R 4 )—, —N(R 4 )—, —N(R 4 )C(O)—, —NR 4 C(O)N(R 4 )—, —N(R 4 )CO 2 —, —C(O)N(R 4 )—, —C(O)—, —C(O)—C(O)—, —CO 2 —, —OC(O)—, —OC(O)O—, —OC(O)N(R 4 )—, —C(NR 4 )═N—, —C(OR 5 )═N—, —N(R 4 )—N(R 4 )—, —N(R 4 )SO 2 —, —N(R 4 )SO 2 N(R 4 )—, —P(O)(R 5 )—, —P(O)(OR 5 )—O—, —P(O)—O—, or —P(O)(NR 5 )—N(R 5 )—;  
 R 2d  is -halo, —NO 2 , —CN, —C(R 5 )═C(R 5 ) 2 , —C(R 5 )═C(R 5 )(R 10 ), —C≡C—R 5 , —C≡C—R 10 , —OR 5 , —SR 6 , —S(O)R 6 , —SO 2 R 6 , —SO 3 R 5 , —SO 2 N(R 4 ) 2 , —N(R 4 ) 2 , —NR 4 C(O)R 5 , —NR 4 C(O)N(R 4 ) 2 , —NR 4 CO 2 R 6 , —O—CO 2 R 5 , —OC(O)N(R 4 ) 2 , —O—C(O)R 5 , —CO 2 R 5 , —C(O)—C(O)R 5 , —C(O)R 5 , —C(O)N(R 4 ) 2 , —C(O)N(R 4 )C(═NR 4 )—N(R 4 ) 2 , —N(R 4 )C(═NR 4 )—N(R 4 )—C(O)R 5 , —C(═NR 4 )—N(R 4 ) 2 , —C(═NR 4 )—OR 5 , —N(R 4 )—N(R 4 ) 2 , —N(R 4 )C(═NR 4 )—N(R 4 ) 2 , —N(R 4 )SO 2 R 6 , —N(R 4 )SO 2 N(R 4 ) 2 , —P(O)(R 4 ) 2 , or —P(O)(OR 5 ) 2 ;  
 each R 3  independently is an optionally substituted aryl, heterocyclyl, or heteroaryl group;  
 each R 3  independently is selected from the group consisting of -halo, —OH, —O(C 1-3  alkyl), —CN, —N(R 4 ) 2 , —C(O)(C 1-3  alkyl), —CO 2 H, —CO 2 (C 1-3  alkyl), —C(O)NH 2 , and —C(O)NH(C 1-3  alkyl);  
 each R 3b  independently is a C 1-3  aliphatic optionally substituted with R 3  or R 7 , or two substituents R 3b  on the same carbon atom, taken together with the carbon atom to which they are attached, form a 3- to 6-membered carbocyclic ring;  
 each R 4  independently is hydrogen or an optionally substituted aliphatic, aryl, heteroaryl, or heterocyclyl group; or two R 4  on the same nitrogen atom, taken together with the nitrogen atom, form an optionally substituted 5- to 6-membered heteroaryl or 4- to 8-membered heterocyclyl ring having, in addition to the nitrogen atom, 0-2 ring heteroatoms selected from N, O, and S; each R 5  independently is hydrogen or an optionally substituted aliphatic, aryl, heteroaryl, or heterocyclyl group;  
 each R 6  independently is an optionally substituted aliphatic or aryl group;  
 each R 7  independently is an optionally substituted aryl, heterocyclyl, or heteroaryl group; and  
 each R 10  independently is —CO 2 R 5  or —C(O)N(R 4 ) 2 .  
 
     
     
         4 . The compound of  claim 2 , wherein Ring A is a substituted or unsubstituted ring selected from the group consisting of furano, thieno, pyrrolo, oxazolo, thiazolo, imidazolo, pyrazolo, isoxazolo, isothiazolo, triazolo, benzo, pyridino, pyridazino, pyrimidino, and pyrazino.  
     
     
         5 . The compound of  claim 2 , having formula (B):  
       
         
           
           
               
               
           
         
       
       or a pharmaceutically acceptable salt thereof;  
       wherein: 
 Ring A is substituted with 0-3 R b ;  
 Ring B is a substituted or unsubstituted aryl, heteroaryl, heterocyclyl, or cycloaliphatic ring; and  
 Ring C is a substituted or unsubstituted aryl, heteroaryl, heterocyclyl, or cycloaliphatic ring.  
 
     
     
         6 . The compound of  claim 5 , wherein: 
 Ring B is a mono- or bicyclic aryl, heteroaryl, heterocyclyl, or cycloaliphatic ring;    each substitutable saturated ring carbon atom in Ring B is unsubstituted or is substituted with ═O, ═S, ═C(R 5 ) 2 , or R c ;    each substitutable unsaturated ring carbon atom in Ring B is unsubstituted or is substituted with R c ;    each substitutable ring nitrogen atom in Ring B is unsubstituted or substituted with R 9c ;    each R c  independently is selected from the group consisting of C 1-6  aliphatic, R 2c , R 7c , —T 1 —R 2c , and —T 1 —R 7c ;    T 1  is a C 1-6  alkylene chain optionally substituted with R 3  or R 3b , wherein T 1  or a portion thereof optionally forms part of a 3- to 7-membered ring;    R 2c  is -halo, —NO 2 , —CN, —C(R 5 )═C(R 5 ) 2 , —C(R 5 )═C(R 5 )(R 10 ), —C≡C—R 5 , —C≡C—R 10 , —OR 5 , —SR 6 , —S(O)R 6 , —SO 2 R 6 , —SO 2 N(R 4 ) 2 , —N(R 4 ) 2 , —NR 4 C(O)R 5 , —NR 4 C(O)N(R 4 ) 2 , —NR 4 CO 2 R 6 , —O—CO 2 R 5 , —OC(O)N(R 4 ) 2 , —O—C(O)R 5 , —CO 2 R 5 , —C(O)—C(O)R 5 , —C(O)R 5 , —C(O)N(R 4 ) 2 , —C(═NR 4 )—N(R 4 ) 2 , —C(═NR 4 )—OR 5 , —N(R 4 )—N(R 4 ) 2 , —N(R 4 )C(═NR 4 )—N(R 4 ) 2 , —N(R 4 )SO 2 R 6 , —N(R 4 )SO 2 N(R 4 ) 2 , —P(O)(R 5 ) 2 , or —P(O)(OR 5 ) 2 ;    each R 7c  independently is an optionally substituted aryl, heterocyclyl, or heteroaryl group;    each R 9c  independently is —C(O)R 5 , —C(O)N(R 4 ) 2 , —CO 2 R 6 , —SO 2 R 6 , —SO 2 N(R 4 ) 2 , or a C 1-4  aliphatic optionally substituted with R 3  or R 7 ; and    Ring C is a mono- or bicyclic aryl, heteroaryl, heterocyclyl, or cycloaliphatic ring;    each substitutable saturated ring carbon atom in Ring C is unsubstituted or is substituted with ═O, ═S, ═C(R 5 ) 2 , or R d ;    each substitutable unsaturated ring carbon atom in Ring C is unsubstituted or is substituted with R d ;    each substitutable ring nitrogen atom in Ring C is unsubstituted or is substituted with R 9d ;    each R d  independently is selected from the group consisting of C 1-6  aliphatic, R 2d , R 7d , —T 2 —R 2d , —T 2 —R 7d , —V—T 3 R 2d , and —V—T 3 —R 7d ;    T 2  is a C 1-6  alkylene chain optionally substituted with R 3  or R 3b , wherein the alkylene chain optionally is interrupted by —C(R 5 )═C(R 5 )—, —C≡C—, —O—, —S—, —S(O)—, —S(O) 2 —, —SO 2 N(R 4 )—, —N(R 4 )—, —N(R 4 )C(O)—, —NR 4 C(O)N(R 4 )—, —N(R 4 )CO 2 —, —C(O)N(R 4 )—, —C(O)—, —C(O)—C(O)—, —CO 2 , —OC(O)—, —OC(O)O—, —OC(O)N(R 4 )—, —N(R 4 )—N(R 4 )—, —N(R 4 )SO 2 —, or —SO 2 N(R 4 )—, and wherein T 2  or a portion thereof optionally forms part of a 3-7 membered ring;    T 3  is a C 1-6  alkylene chain optionally substituted with R 3  or R 3b , wherein the alkylene chain optionally is interrupted by —C(R 5 )═C(R 5 )—, —C≡C—, —O—, —S—, —S(O)—, —S(O) 2 —, —SO 2 N(R 4 )—, —N(R 4 )—, —N(R 4 )C(O)—, —NR 4 C(O)N(R 4 )—, —N(R 4 ) CO 2 —, —C(O)N(R 4 )—, —C(O)—, —C(O)—C(O)—, —CO 2 —, —OC(O)—, —OC(O)O—, —OC(O)N(R 4 )—, —N(R 4 )—N(R 4 )—, —N(R 4 )SO 2 —, or —SO 2 N(R 4 )—, and wherein T 3  or a portion thereof optionally forms part of a 3-7 membered ring;    V is —C(R 5 )═C(R 5 )—, —C≡C—, —O—, —S—, —S(O)—, —S(O) 2 —, —SO 2 N(R 4 )—, —N(R 4 )—, —N(R 4 )C(O)—, —NR 4 C(O)N(R 4 )—, —N(R 4 )CO 2 —, —C(O)N(R 4 )—, —C(O)—, —C(O)—C(O)—, —CO 2 —, —OC(O)—, —OC(O)O—, —OC(O)N(R 4 )—, —C(NR 4 )═N—, —C(OR 5 )═N—, —N(R 4 )—N(R 4 )—, —N(R 4 )SO 2 —, —N(R 4 )SO 2 N(R 4 )—, —P(O)(R 5 )—, —P(O)(OR 5 )—O—, —P(O)—O—, or —P(O)(NR 5 )—N(R 5 )—;    R 2d  is -halo, —NO 2 , —CN, —C(R 5 )═C(R 5 ) 2 , —C(R 5 )═C(R 5 )(R 10 ), —C≡C—R 5 , —C≡C—R 10 , —OR 5 , —SR 6 , —S(O)R 6 , —SO 2 R 6 , —SO 3 R 5 , —SO 2 N(R 4 ) 2 , —N(R 4 ) 2 , —NR 4 C(O)R 5 , —NR 4 C(O)N(R 4 ) 2 , —NR 4 CO 2 R 6 , —O—CO 2 R 5 , —OC(O)N(R 4 ) 2 , —O—C(O)R 5 , —CO 2 R 5 , —C(O)—C(O)R 5 , —C(O)R 5 , —C(O)N(R 4 ) 2 , —C(O)N(R 4 )C(═NR 4 )—N(R 4 ) 2 , —N(R 4 )C(═NR 4 )—N(R 4 )—C(O)R 5 , —C(═NR 4 )—N(R 4 ) 2 , —C(═NR 4 )—OR 5 , —N(R 4 )—N(R 4 ) 2 , —N(R 4 )C(═NR 4 )—N(R 4 ) 2 , —N(R 4 )SO 2 R 6 , —N(R 4 )SO 2 N(R 4 ) 2 , —P(O)(R 5 ) 2 , or —P(O)(OR 5 ) 2 ;    each R 7d  independently is an optionally substituted aryl, heterocyclyl, or heteroaryl group; and    each R 9d  independently is —C(O)R 5 , —C(O)N(R 4 ) 2 , —CO 2 R 6 , —SO 2 R 6 , —SO 2 N(R 4 ) 2 , or a C 1-4  aliphatic optionally substituted with R 3  or R 7 .    
     
     
         7 . The compound of  claim 1 , having formula (II):  
       
         
           
           
               
               
           
         
       
       or a pharmaceutically acceptable salt thereof;  
       wherein: 
 R e  is hydrogen or a C 1-3  aliphatic optionally substituted with R 3  or R 7 ;  
 Ring A is substituted with 0-3 R b ; 
 each R b  independently is selected from the group consisting of C 1-6  aliphatic, R 2b , R 7b , —T 1 —R 2b , and —T 1 —R 7b ; 
 each R 2b  independently is -halo, —NO 2 , —CN, —C(R 5 )═C(R 5 ) 2 , —C≡C—R 5 , —OR 5 , —SR 6 , —S(O)R 6 , —SO 2 R 6 , —SO 2 N(R 4 ) 2 , —N(R 4 ) 2 , —NRR 4 C(O)R 5 , —NR 4 C(O)N(R 4 ) 2 , —NR 4 CO 2 R 6 , —O—CO 2 R 5 , —OC(O)N(R 4 ) 2 , —O—C(O)R 5 , —CO 2 R 5 , —C(O)—C(O)R 5 , —C(O)R 5 , —C(O)N(R 4 ) 2 , —C(═NR 4 )—N(R 4 ) 2 , —C(═NR 4 )—OR 5 , —N(R 4 )—N(R 4 ) 2 , —N(R 4 )C(═NR 4 )—N(R 4 ) 2 , —N(R 4 )SO 2 R 6 , —N(R 4 )SO 2 N(R 4 ) 2 , —P(O)(R 5 ) 2 , or —P(O)(OR 5 ) 2 ;  
 each R b  independently is an optionally substituted aryl, heterocyclyl, or heteroaryl group;  
 
 
 Ring B is an aryl or heteroaryl ring substituted with 0-2 independently selected R c  and 0-3 independently selected R 2c  or C 1-6  aliphatic groups; 
 each R c  independently is selected from the group consisting of C 1-6  aliphatic, R 2c , R 7c , —T—R 2c , and —T 1 —R 7c ; 
 each R 2c  independently is -halo, —NO 2 , —CN, —C(R 5 )═C(R 5 ) 2 , —C≡C—R 5 , —OR 5 , —SR 6 , —S(O)R 6 , —SO 2 R 6 , —SO 2 N(R 4 ) 2 , —N(R 4 ) 2 , —NR 4 C(O)R 5 , —NR 4 C(O)N(R 4 ) 2 , —NR 4 CO 2 R 6 , —O—CO 2 R 5 , —OC(O)N(R 4 ) 2 , —O—C(O)R 5 , —CO 2 R 5 , —C(O)—C(O)R 5 , —C(O)R 5 , —C(O)N(R 4 ) 2 , —C(═NR 4 )—N(R 4 ) 2 , —C(═NR 4 )—OR 5 , —N(R 4 )—N(R 4 ) 2 , —N(R 4 )C(═NR 4 )—N(R 4 ) 2 , —N(R 4 )SO 2 R 6 , —N(R 4 )SO 2 N(R 4 ) 2 , —P(O)(R 5 ) 2 , or —P(O)(OR 5 ) 2 ;  
 each R 7c  independently is an optionally substituted aryl, heterocyclyl, or heteroaryl group;  
 
 
 T 1  is a C 1-6  alkylene chain optionally substituted with R 3  or R 3b , wherein T 1  or a portion thereof optionally forms part of a 3- to 7-membered ring;  
 Ring C is aryl or heteroaryl ring substituted with 0-2 independently selected R d  and 0-3 independently selected R 2d  or C 1-6  aliphatic groups; 
 each R d  independently is selected from the group consisting of C 1-6  aliphatic, R 2d , R 7d , —T 1 —R 2d , —T 2 —R 7d , —V—T 3 —R 2d , and —V—T 3 —R 7d ;  
 T 2  is a C 1-6  alkylene chain optionally substituted with R 3  or R 3b , wherein the alkylene chain optionally is interrupted by —C(R 5 )═C(R 5 )—, —C≡C—, —O—, —S—, —S(O)—, —S(O) 2 —, —SO 2 N(R 4 )—, —N(R 4 )—, —N(R 4 )C(O)—, —NR 4 C(O)N(R 4 )—, —N(R 4 )CO 2 —, —C(O)N(R 4 )—, —C(O)—, —C(O)—C(O)—, —CO 2 —, —OC(O)—, —OC(O)O—, —OC(O)N(R 4 )—, —N(R 4 )—N(R 4 )—, —N(R 4 )SO 2 —, or —SO 2 N(R 4 )—, and wherein T 2  or a portion thereof optionally forms part of a 3-7 membered ring;  
 T 3 is a C 1-6  alkylene chain optionally substituted with R 3  or R 3b , wherein the alkylene chain optionally is interrupted by —C(R 5 )═C(R 5 )—, —C≡C—, —O—, —S—, —S(O)—, —S(O) 2 —, —SO 2 N(R 4 )—, —N(R 4 )—, —N(R 4 )C(O)—, —NR 4 C(O)N(R 4 )—, —N(R 4 )CO 2 —, —C(O)N(R 4 )—, —C(O)—, —C(O)—C(O)—, —CO 2 —, —OC(O)—, —OC(O)O—, —OC(O)N(R 4 )—, —N(R 4 )—N(R 4 )—, —N(R 4 )SO 2 —, or —SO 2 N(R 4 )—, and wherein T 3  or a portion thereof optionally forms part of a 3-7 membered ring;  
 V is —C(R 5 )═C(R 5 )—, —C≡C—, —O—, —S—, —S(O)—, —S(O) 2 —, —SO 2 N(R 4 )—, —N(R 4 )—, —N(R 4 )C(O)—, —NR 4 C(O)N(R 4 )—, —N(R 4 )CO 2 —, —C(O)N(R 4 )—, —C(O)—, —C(O)—C(O)—, —CO 2 —, —OC(O)—, —OC(O)O—, —OC(O)N(R 4 )—, —C(NR 4 )═N—, —C(OR 5 )═N—, —N(R 4 )—N(R 4 )—, —N(R 4 )SO 2 —, —N(R 4 )SO 2 N(R 4 )—, —P(O)(R 5 )—, —P(O)(OR 5 )—O—, —P(O)—O—, or —P(O)(NR 5 )—N(R 5 )—;  
 R 2d  is -halo, —NO 2 , —CN, —C(R 5 )═C(R 5 ) 2 , —C≡C—R 5 , —OR 5 , —SR 6 , —S(O)R 6 , —SO 2 R 5 , —SO 2 N(R 4 ) 2 , —N(R 4 ) 2 , —NR 4 C(O)R 5 , —NR 4 C(O)N(R 4 ) 2  —NR 4 CO 2 R 6 , —O—CO 2 R 5 , —OC(O)N(R 4 ) 2 , —O—C(O)R 5 , —CO 2 R 5 , —C(O)—C(O)R 5 , —C(O)R 5 , —C(O)N(R 4 ) 2 , —C(═NR 4 )—N(R 4 ) 2 , —C(═NR 4 )—OR 5 , —N(R 4 )—N(R 4 ) 2 , —N(R 4 )C(═NR 4 )—N(R 4 ) 2 , —N(R 4 )SO 2 R 6 , —N(R 4 )SO 2 N(R 4 ) 2 , —P(O)(R 5 ) 2 , or —P(O)(OR 5 ) 2 ; and  
 each R 7d  independently is an optionally substituted aryl, heterocyclyl, or heteroaryl group.  
 
 each R 3  independently is selected from the group consisting of -halo, —OH, —O(C 1-3  alkyl), —CN, —N(R 4 ) 2 , —C(O)(C 1-3  alkyl), —CO 2 H, —CO 2 (C 1-3  alkyl), —C(O)NH 2 , and —C(O)NH(C 1-3  alkyl);  
 each R 3b  independently is a C 1-3  aliphatic optionally substituted with R 3  or R 7 , or two substituents R 3b  on the same carbon atom, taken together with the carbon atom to which they are attached, form a 3- to 6-membered carbocyclic ring;  
 each R 4  independently is hydrogen or an optionally substituted aliphatic, aryl, heteroaryl, or heterocyclyl group; or two R 4  on the same nitrogen atom, taken together with the nitrogen atom, form an optionally substituted 5- to 8-membered heteroaryl or heterocyclyl ring having, in addition to the nitrogen atom, 0-2 ring heteroatoms selected from N, O, and S;  
 each R 5  independently is hydrogen or an optionally substituted aliphatic, aryl, heteroaryl, or heterocyclyl group;  
 each R 6  independently is an optionally substituted aliphatic or aryl group; and  
 each R 7  independently is an optionally substituted aryl, heterocyclyl, or heteroaryl group.  
 
     
     
         8 . The compound of  claim 7 , wherein Ring B is a substituted or unsubstituted mono- or bicyclic aryl or heteroaryl ring selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, thiadiazolyl, phenyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, indolizinyl, indolyl, isoindolyl, indazolyl, benzo[b]furanyl, benzo[b]thienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolyl, isoquinolyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, and pteridinyl.  
     
     
         9 . The compound of  claim 7 , wherein Ring B is a substituted or unsubstituted phenyl or pyridyl ring.  
     
     
         10 . The compound of  claim 9 , having formula (IIa):  
       
         
           
           
               
               
           
         
       
       wherein: 
 Ring A is substituted with 0-2 independently selected R b ; and  
 Ring B is substituted with 0-2 independently selected R c .  
 
     
     
         11 . The compound of  claim 10 , characterized by at least one of the following features: 
 (a) each R b  independently is selected from the group consisting of C 1-3  aliphatic,R 2b , R 7b , —T 1 —R 2b , and —T 1 —R 7b , where T 1  is a C 1-3  alkylene chain optionally substituted with fluoro, and each R 2b  independently is selected from the group consisting of -halo, —NO 2 , —C(R 5 )═C(R 5 ) 2 , —C≡C—R 5 , —C≡C—R 5 , —OR 5 , —N(R 4 ) 2 , —CO 2 R 5 , and —C(O)N(R 4 ) 2 ;    (b) each R c  independently is selected from the group consisting of C 1-3  aliphatic, R 2c , R 7c , —T 1 —R 2c , and —T 1 —R 7c , where T 1  is a C 1-3  alkylene chain optionally substituted with fluoro, and each R 2c  independently is selected from the group consisting of -halo, —NO 2 , —C(R 5 )═C(R 5 ) 2 , —C≡C—R 5 , —OR 5 , and —N(R 4 ) 2 ; and    (c) R e  is hydrogen.    
     
     
         12 . The compound of  claim 11 , having formula (IIIa):  
       
         
           
           
               
               
           
         
       
       wherein: 
 each of R b2  and R b3  independently is hydrogen or R b ; 
 R b  is selected from the group consisting of C 1-3  aliphatic, C 1-3  fluoroaliphatic, and R 2b ;  
 R 2b  is selected from the group consisting of -halo, —NO 2 , —C(R 5 )═C(R 5 ) 2 , —C≡C—R 5 , —OR 5 , —N(R 4 ) 2 , —CO 2 R 5 , —C(O)N(R 4 ) 2 ;  
 
 each of R c1  and R c5  independently is hydrogen or R c ; 
 R c  is selected from the group consisting of C 1-3  aliphatic, C 1-3  fluoroaliphatic, and R 2c ; and  
 R 2c  is selected from the group consisting of -halo, —NO 2 , —C(R 5 )═C(R 5 ) 2 , —C≡C—R 5 , —OR 5 , and —N(R 4 ) 2    
 
 
     
     
         13 . The compound of  claim 12 , wherein: 
 R e  is hydrogen;    each of R b2  and R b3  independently is selected from the group consisting of hydrogen, -halo, C 1-3  aliphatic, C 1-3  fluoroaliphatic, and —OR 5 , where R 5  is hydrogen or C 1-3  aliphatic; and    each of R c1  and R c5  independently is selected from the group consisting of hydrogen, -halo, C 1-3  aliphatic, C 1-3  fluoroaliphatic, and —OR 5 , where R 5  is hydrogen or C 1-3  aliphatic.    
     
     
         14 . The compound of  claim 7 , having formula (IV):  
       
         
           
           
               
               
           
         
       
       wherein: 
 Ring A is substituted with 0-2 R b ;  
 Ring B is a mono- or bicyclic aryl or heteroaryl ring, which is substituted with 0-2 independently selected R c  and 0-2 independently selected R 2c  or C 1-6  aliphatic groups;  
 R e  is hydrogen or a C 1-3  aliphatic optionally substituted with R 3  or R 7 ;  
 R g  is selected from the group consisting of hydrogen, C 1-6  aliphatic, and R 2d ;  
 each of R h  and R k  independently is hydrogen or R d ;  
 each R d  independently is selected from the group consisting of C 1-3  aliphatic, R 2d , R 7d , —T 2 —R 2d , —T 2 —R 7d , —V—T 3 —R 2d , and —V—T 3 —R 7d ; and  
 each R 2d  independently is selected from the group consisting of -halo, —OR 5 , —CO 2 R 5 , —C(O)N(R 4 ) 2  —SO 2 N(R 4 ) 2 , —C(═NR 4 )N(R 4 ) 2 , —C(O)N(R 4 )C(═NR 4 )—N(R 4 ) 2 , —N(R 4 )C(═NR 4 )—N(R 4 )—C(O)R 5 , and —NR 4 C(O)R 5 .  
 
     
     
         15 . The compound of  claim 14 , wherein each of R g  and R k  is hydrogen, and R h  is —CO 2 R 5 , —C(O)N(R 4 ) 2 , —C(═NR 4 )N(R 4 ) 2 , or —N(R 4 )C(O)R 5    
     
     
         16 . The compound of  claim 7 , having formula (Va):  
       
         
           
           
               
               
           
         
       
       wherein: 
 R e  is hydrogen;  
 each of R b2  and R b3  independently is selected from the group consisting of hydrogen, -halo, C 1-3  aliphatic, C 1-3  fluoroaliphatic, and —OR 5 , where R 5  is hydrogen or C 1-3  aliphatic; and  
 each of R c1  and R c5  independently is selected from the group consisting of hydrogen, -halo, C 1-3  aliphatic, C 1-3  fluoroaliphatic, and —OR 5 , where R 5  is hydrogen or C 1-3  aliphatic;  
 R g  is selected from the group consisting of hydrogen, C 1-6  aliphatic, and R 2d ; and  
 each of R h  and R k  independently is hydrogen or R d .  
 
     
     
         17 . A pharmaceutical composition comprising a compound according to  claim 1  and a pharmaceutically acceptable carrier.  
     
     
         18 . A method for inhibiting Aurora kinase activity in a cell, comprising contacting a cell in which inhibition of Aurora kinase is desired with a compound according to  claim 1 .  
     
     
         19 . A method for treating cancer in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of a compound according to  claim 1.