Acetyl 2-hydroxy-1,3-diaminoalkanes

Abstract

Disclosed are compounds of the formula: where variables Z, X, R 15 , R 2 , R 3 , and R c are defined herein. Compounds disclosed herein are inhibitors of the beta-secretase enzyme and are therefore useful in the treatment of Alzheimer's disease and other diseases characterized by deposition of A beta peptide in a mammal.

1 . A compound of the formula I: 
       
         
           
           
               
               
           
         
       
       or pharmaceutically acceptable salts thereof, wherein
 Z is hydrogen, or 
 Z is (C 3 -C 7  cycloalkyl) 0-1 (C 1 -C 6  alkyl)-, (C 3 -C 7  cycloalkyl) 0-1 (C 2 -C 6  alkenyl)-, (C 3 -C 7  cycloalkyl) 0-1 (C 2 -C 6  alkynyl)- or (C 3 -C 7  cycloalkyl)-, wherein each of said groups is optionally substituted with 1, 2, or 3 R z  groups, wherein 1 or 2 methylene groups within said (C 3 -C 7  cycloalkyl) 0-1 (C 1 -C 6  alkyl)-, (C 3 -C 7  cycloalkyl) 0-1 (C 2 -C 6  alkenyl)-, (C 3 -C 7  cycloalkyl) 0-1 (C 2 -C 6  alkynyl)- or (C 3 -C 7  cycloalkyl)- groups are optionally replaced with —(C═O)—;
 R z  at each occurrence is independently halogen (in one aspect, F or Cl), —OH, —SH, —CN, —CF 3 , —OCF 3 , C 1 -C 6  alkoxy, C 3 -C 7  cycloalkyl, C 3 -C 7  cycloalkoxy or —NR 100 R 101 ;
 R 100  and R 101  at each occurrence are independently H, C 1 -C 6  alkyl, phenyl, CO(C 1 -C 6 alkyl) or SO 2 C 1 -C 6  alkyl; 
 
 
 X is —(C═O)— or —(SO 2 )—; 
 R 1  is C 1 -C 10  alkyl optionally substituted with 1, 2, or 3 groups independently selected from halogen, —OH, ═O, —SH, —CN, —CF 3 , —C 3-7  cycloalkyl, —C 1 -C 4  alkoxy, amino, mono- or dialkylamino, aryl, heteroaryl, and heterocycloalkyl,
 wherein each aryl group is optionally substituted with 1, 2 or 3 R 50  groups; each heteroaryl is optionally substituted with 1 or 2 R 50  groups; and each heterocycloalkyl group is optionally substituted with 1 or 2 groups that are independently R 50  or ═O; 
 R 50  is selected from halogen, OH, SH, CN, —CO—(C 1 -C 4  alkyl), —NR 7 R 8 , —S(O) 0-2 —(C 1 -C 4  alkyl), C 1 -C 6  alkyl, C 2 -C 6  alkenyl, C 2 -C 6  alkynyl, C 1 -C 6  alkoxy and C 3 -C 8  cycloalkyl; wherein
 the alkyl, alkenyl, alkynyl, alkoxy and cycloalkyl groups are optionally substituted with 1 or 2 substituents independently selected from C 1 -C 4  alkyl, halogen, OH, —NR 5 R 6 , CN, C 1 -C 4  haloalkoxy, NR 7 R 8 , and C 1 -C 4  alkoxy; wherein
 R 5  and R 6  are independently H or C 1 -C 6  alkyl; or 
 R 5  and R 6  and the nitrogen to which they are attached form a 5 or 6 membered heterocycloalkyl ring; 
 
 R 7  and R 8  are independently selected from H; —C 1 -C 4  alkyl optionally substituted with 1, 2, or 3 groups independently selected from —OH, —NH 2 , and halogen; —C 3 -C 6  cycloalkyl; —(C 1 -C 4  alkyl)-β—(C 1 -C 4  alkyl); —C 2 -C 4  alkenyl; and —C 2 -C 4  alkynyl; 
 
 
 R 2  and R 3  are independently selected from H; F; —C 1 -C 6  alkyl optionally substituted with —F, —OH, —C≡N, —CF 3 , C 1 -C 3  alkoxy, or —NR 5 R 6 ; —(CH 2 ) 0-2 —R 17 ; —(CH 2 ) 0-2 —R 18 ; —C 2 -C 6  alkenyl or C 2 -C 6  alkynyl, wherein the alkenyl and alkynyl groups are optionally substituted with 1 or 2 groups that are independently —F, —OH, —C≡N, —CF 3  or C 1 -C 3  alkoxy; —(CH 2 ) 0-2 —C 3 -C 7  cycloalkyl, which is optionally substituted with 1 or 2 groups that are independently —F, —OH, —C≡N, —CF 3 , C 1 -C 3  alkoxy and —NR 5 R 6 ;
 R 17  at each occurrence is an aryl group (preferably selected from phenyl, 1-naphthyl, 2-naphthyl, indanyl, indenyl, dihydronaphthyl and tetralinyl) wherein said aryl group is optionally substituted with one or two groups that are independently —C 1 -C 3  alkyl; —C 1 -C 4  alkoxy; CF 3 ; —C 2 -C 6  alkenyl or —C 2 -C 6  alkynyl each of which is optionally substituted with one substituent selected from F, OH, C 1 -C 3  alkoxy; halogen; OH; —C≡N; —C 3 -C 7  cycloalkyl; —CO—(C 1 -C 4  alkyl); or —SO 2 —(C 1 -C 4  alkyl); 
 R 18  is a heteroaryl group (preferably selected from pyridinyl, pyrimidinyl, quinolinyl, indolyl, pyridazinyl, pyrazinyl, isoquinolyl, quinazolinyl, quinoxalinyl, phthalazinyl, imidazolyl, isoxazolyl, oxazolyl, thiazolyl, furanyl, thienyl, pyrrolyl, oxadiazolyl or thiadiazolyl) wherein said heteroaryl groups are optionally substituted with one or two groups that are independently —C 1 -C 6  alkyl optionally substituted with one substituent selected from OH, CF 3 , C 1 -C 3  alkoxy, and —NR 5 R 6 ; 
 
 R 15  is selected from hydrogen, C 1 -C 6  alkyl, C 1 -C 6  alkoxy, C 1 -C 6  alkoxy C 1 -C 6  alkyl, hydroxy C 1 -C 6  alkyl, halo C 1 -C 6  alkyl, each of which is unsubstituted or substituted with 1, 2, 3, or 4 groups independently selected from halogen, C 1 -C 6  alkyl, hydroxy, C 1 -C 6  alkoxy, and NH 2 , and —R 26 -R 27 ; wherein
 R 26  is selected from a bond, —C(O)—, —SO 2 —, —CO 2 —, —C(O)NR 5 —, and —NR 5 C(O)—, 
 R 27  is selected from C 1 -C 6  alkyl, C 1 -C 6  alkoxy, aryl C 1 -C 6  alkyl, heterocycloalkyl, and heteroaryl, wherein each of the above is unsubstituted or substituted with 1, 2, 3, 4, or 5 groups that are independently C 1 -C 4  alkyl, C 1 -C 4  alkoxy, halogen, haloalkyl, hydroxyalkyl, —NR 5 R 6 , or —C(O)NR 5 R 6 ; or 
 
 R 2 , R 3  and the carbon to which they are attached form a C 3 -C 7  carbocycle, wherein 1, 2, or 3 carbon atoms are optionally replaced by groups that are independently selected from —O—, —S—, —SO 2 —, —C(O)—, or —NR 7 —; 
 R c  is selected from —(CH 2 ) 0-3 —(C 3 -C 6 ) cycloalkyl wherein the cycloalkyl is optionally substituted with 1, 2, or 3 groups independently selected from —R 205 ; and —CO 2 —(C 1 -C 4  alkyl); —(CR 245 R 250 ) 0-4 -aryl; —(CR 245 R 250 ) 0-4 -heteroaryl; —(CR 245 R 250 ) 0-4 -heterocycloalkyl; —(CR 245 R 250 ) 0-4 -aryl-heteroaryl; —(CR 245 R 250 ) 0-4 -aryl-heterocycloalkyl; —(CR 245 R 250 ) 0-4 -aryl-aryl; —(CR 245 R 250 ) 0-4 -heteroaryl-aryl; —(CR 245 R 250 ) 0-4 -heteroaryl-heterocycloalkyl; —(CR 245 R 250 ) 0-4 -heteroaryl-heteroaryl; —CHR 245 —CHR 250 -aryl; —(CR 245 R 250 ) 0-4 —(CR 245 R 250 ) 0-4 -heterocycloalkyl-heterocycloalkyl; —(CR 245 R 250 ) 0-4 -heterocycloalkyl-aryl; a monocyclic or bicyclic ring of 5, 6, 7 8, 9, or 10 carbons fused to 1 or 2 aryl (preferably phenyl), heteroaryl (preferably pyridyl, imidazolyl, thienyl, thiazolyl, or pyrimidyl), or heterocycloalkyl (preferably piperidinyl or piperazinyl) groups;
 wherein 1, 2 or 3 carbons of the monocyclic or bicyclic ring are optionally replaced with —NH—, —N(CO) 0-1 R 215 —N(CO) 0-1 R 220 —, —O—, or —S(═O) 0-2 —, and wherein the monocyclic or bicyclic ring is optionally substituted with 1, 2 or 3 groups that are independently —R 205 , —R 245 , —R 250  or ═O; 
 and —C 2 -C 6  alkenyl optionally substituted with 1, 2, or 3 R 205  groups; 
 wherein each aryl or heteroaryl group attached directly or indirectly to the —(CR 245 R 250 ) 0-4  group is optionally substituted with 1, 2, 3 or 4 R 200  groups; 
 wherein each heterocycloalkyl attached directly or indirectly to the —(CR 245 R 250 ) 0-4  group is optionally substituted with 1, 2, 3, or 4 R 210 ; 
 R 200  at each occurrence is independently selected from —C 1 -C 6  alkyl optionally substituted with 1, 2, or 3 R 205  groups; —OH; —NO 2 ; -halogen; —C≡N; —(CH 2 ) 0-4 —CO—NR 220 R 225 ; —(CH 2 ) 0-4 —CO—(C 1 -C 8  alkyl); —(CH 2 ) 0-4 —CO—(C 2 -C 8  alkenyl); —(CH 2 ) 0-4 —CO—(C 2 -C 8  alkynyl); —(CH 2 ) 0-4 —CO—(C 3 -C 7  cycloalkyl); —(CH 2 ) 0-4 —(CO) 0-1 -aryl (preferably phenyl); —(CH 2 ) 0-4 —(CO) 0-1 -heteroaryl (preferably pyridyl, pyrimidyl, furanyl, imidazolyl, thienyl, oxazolyl, thiazolyl, or pyrazinyl); —(CH 2 ) 0-4 —(CO) 0-1 -heterocycloalkyl (preferably imidazolidinyl, piperazinyl, pyrrolidinyl, piperidinyl, or tetrahydropyranyl); —(CH 2 ) 0-4 —CO 2 R 215 ; —(CH 2 ) 0-4 —SO 2 —NR 220 R 225 ; —(CH 2 ) 0-4 —S(O) 0-2 —(C 1 -C 8  alkyl); —(CH 2 ) 0-4 —S(O) 0-2 —(C 3 -C 7  cycloalkyl); —(CH 2 ) 0-4 —N(H or R 215 )—CO 2 R 215 ; —(CH 2 ) 0-4 —N(H or R 215 ) —SO 2 —R 220 ; —(CH 2 ) 0-4 —N(H or R 215 )—CO—N(R 215 ) 2 ; —(CH 2 ) 0-4 —N(—H or R 215 )—CO—R 220 ; —(CH 2 ) 0-4 —NR 220 R 225 ; —(CH 2 ) 0-4 —O—CO—(C 1 -C 6  alkyl); —(CH 2 ) 0-4 —O—(R 215 ); —(CH 2 ) 0-4 —S—(R 215 ); —(CH 2 ) 0-4 —O—(C 1 -C 6  alkyl optionally substituted with 1, 2, 3, or 5 —F); —C 2 -C 6  alkenyl optionally substituted with 1 or 2 R 205  groups; —C 2 -C 6  alkynyl optionally substituted with 1 or 2 R 205  groups; adamantly, and —(CH 2 ) 0-4 —C 3 -C 7  cycloalkyl;
 each aryl and heteroaryl group included within R 200  is optionally substituted with 1, 2, or 3 groups that are independently —R 205 , —R 210  or —C 1 -C 6  alkyl substituted with 1, 2, or 3 groups that are independently R 205  or R 210 ; 
 each heterocycloalkyl group included within R 200  is optionally substituted with 1, 2, or 3 groups that are independently R 210 ; 
 R 205  at each occurrence is independently selected from —C 1 -C 6  alkyl, —C 2 -C 6  alkenyl, —C 2 -C 6  alkynyl, —C 1 -C 6  haloalkoxy, —(CH 2 ) 0-3 (C 3 -C 7  cycloalkyl), -halogen, —(CH 2 ) 0-6 —OH, —O-phenyl, OH, SH, —(CH 2 ) 0-6 —C≡N, —(CH 2 ) 0-6 —C(═O)NR 235 R 240 , —CF 3 , —C 1 -C 6  alkoxy, C 1 -C 6  alkoxycarbonyl, and —NR 235 R 240 ; 
 R 210  at each occurrence is independently selected from —C 1 -C 6  alkyl optionally substituted with 1, 2, or 3 R 205  groups; —C 2 -C 6  alkenyl optionally substituted with 1, 2, or 3 R 205  groups; C 1 -C 6  alkanoyl; —SO 2 —(C 1 -C 6  alkyl); —C 2 -C 6  alkynyl optionally substituted with 1, 2, or 3 R 205  groups; -halogen; —C 1 -C 6  alkoxy; —C 1 -C 6  haloalkoxy; —NR 220 R 225 ; —OH; —C≡N; —C 3 -C 7  cycloalkyl optionally substituted with 1, 2, or 3 R 205  groups; —CO—(C 1 -C 4  alkyl); —SO 2 —NR 235 R 240 ; —CO—NR 235 R 240 ; —SO 2 —(C 1 -C 4  alkyl); and ═O; 
 R 215  at each occurrence is independently selected from —C 1 -C 6  alkyl, —(CH 2 ) 0-2 — (aryl), —C 2 -C 6  alkenyl, —C 2 -C 6  alkynyl, —C 3 -C 7  cycloalkyl, —(CH 2 ) 0-2 -(heteroaryl) and —(CH 2 ) 0-2 —(heterocycloalkyl); wherein the aryl group included within R 215  is optionally substituted with 1, 2, or 3 groups that are independently —R 205  or —R 210 ; wherein the heterocycloalkyl and heteroaryl groups included within R 215  are optionally substituted with 1, 2, or 3 R 210 ; 
 R 220  and R 225  at each occurrence are independently H, —C 1 -C 6  alkyl, —CHO, hydroxy C 1 -C 6  alkyl, C 1 -C 6  alkoxycarbonyl, -amino C 1 -C 6  alkyl, —SO 2 —C 1 -C 6  alkyl, C 1 -C 6  alkanoyl optionally substituted with up to three halogens, —C(O)NH 2 , —C(O)NH(C 1 -C 6  alkyl), —C(O)N(C 1 -C 6  alkyl)(C 1 -C 6  alkyl), -halo C 1 -C 6  alkyl, —(CH 2 ) 0-2 —(C 3 -C 7  cycloalkyl), —(C 1 -C 6  alkyl)-O—(C 1 -C 6  alkyl), —C 2 -C 6  alkenyl, —C 2 -C 6  alkynyl, -aryl (preferably phenyl), -heteroaryl, or -heterocycloalkyl; wherein the aryl, heteroaryl and heterocycloalkyl groups included within R 220  and R 225  is optionally substituted with 1, 2, or 3 R 270  groups,
 R 270  at each occurrence is independently —R 205 , —C 1 -C 6  alkyl optionally substituted with 1, 2, or 3 R 205  groups; —C 2 -C 6  alkenyl optionally substituted with 1, 2, or 3 R 205  groups; —C 2 -C 6  alkynyl optionally substituted with 1, 2, or 3 R 205  groups; —phenyl; -halogen; —C 1 -C 6  alkoxy; —C 1 -C 6  haloalkoxy; —NR 235 R 240 ; —OH; —C≡N; —C 3 -C 7  cycloalkyl optionally substituted with 1, 2, or 3 R 205  groups; —CO—(C 1 -C 4  alkyl); —SO 2 —NR 235 R 240 ; —CO—NR 235 R 240 ; —SO 2 —(C 1 -C 4  alkyl); and ═O; 
 R 235  and R 240  at each occurrence are independently —H, —C 1 -C 6  alkyl, C 2 -C 6  alkanoyl, —SO 2 —(C 1 -C 5  alkyl), or -phenyl; 
 
 
 R 245  and R 250  at each occurrence are independently selected from H, —(CH 2 ) 0-4 CO 2 C 1 -C 4  alkyl, —(CH 2 ) 0-4 C(═O)C 1 -C 4  alkyl, —C 1 -C 4  alkyl, —C 1 -C 4  hydroxyalkyl, —C 1 -C 4  alkoxy, —C 1 -C 4  haloalkoxy, —(CH 2 ) 0-4 —C 2 -C 7  cycloalkyl, —C 2 -C 6  alkenyl, —C 2 -C 6  alkynyl, —(CH 2 ) 0-4  aryl, —(CH 2 ) 0-4  heteroaryl, and —(CH 2 ) 0-4  heterocycloalkyl, or 
 R 245  and R 250  are taken together with the carbon to which they are attached to form a monocycle or bicycle of 3, 4, 5, 6, 7 or 8 carbon atoms, where 1, 2, or 3 carbon atoms are optionally replaced by 1, 2, or 3 groups that are independently —O—, —S—, —SO 2 —, —C(O)—, —NR 220 —, or —NR 220 R 220 — wherein both R 220  groups are alkyl; and wherein the ring is optionally substituted with 1, 2, 3, 4, 5, or 6 groups that are independently C 1 -C 4  alkyl, C 1 -C 4  alkoxy, hydroxyl, NH 2 , NH(C 1 -C 6  alkyl), N(C 1 -C 6  alkyl)(C 1 -C 6  alkyl), —NH—C(O)C 1 -C 6  alkyl, —NH—SO 2 —(C 1 -C 6  alkyl), or halogen;
 wherein the aryl, heteroaryl or heterocycloalkyl groups included within R 245  and R 250  are optionally substituted with 1, 2, or 3 groups that are independently halogen, C 1-6  alkyl, CN or OH. 
 
 
 
     
     
         2 . A compound according to  claim 1 , wherein Z is (C 3 -C 7  cycloalkyl) 0-1 (C 1 -C 6  alkyl)-, (C 3 -C 7  cycloalkyl) 0-1 (C 2 -C 6  alkenyl)-, (C 2 -C 7  cycloalkyl) 0-1 (C 2 -C 6  alkynyl)- or (C 2 -C 7  cycloalkyl)-, wherein each of said groups is optionally substituted with 1, 2, or 3 R z  groups;
 wherein, R z  at each occurrence is independently halogen, —OH, —CN, C 1 -C 6  alkoxy, C 3 -C 7  cycloalkyl, C 2 -C 7  cycloalkoxy, —NR 100 R 101 ;   where R 100  and R 101  are independently H, C 1 -C 6  alkyl, phenyl, CO(C 1 -C 6  alkyl) or SO 2 C 1 -C 6  alkyl.   
     
     
         3 . A compound according to  claim 1 , wherein X is —(C═O)—. 
     
     
         4 . A compound according to  claim 3 , wherein Z is H. 
     
     
         5 . A compound according to  claim 1 , wherein R 1  is C 1 -C 10  alkyl optionally substituted with 1 or 2 groups independently selected from halogen, —OH, ═O, —CF 2 , —OCF 3 , cycloalkyl, —C 1 -C 4  alkoxy, amino or aryl, wherein the aryl group is optionally substituted with 1 or 2 R 50  groups;
 wherein R 50  is selected from halogen, OH, —CO—(C 1 -C 4  alkyl), —NR 7 R 8 , C 1 -C 6  alkyl, C 1 -C 6  alkoxy and C 3 -C 8  cycloalkyl;
 wherein the alkyl, alkoxy and cycloalkyl groups are optionally substituted with 1 or 2 substituents independently selected from C 1 -C 4  alkyl, halogen, OH, —NR 5 R 6 , NR 7 R 8 , and C 1 -C 4  alkoxy;
 wherein R 5  and R 6  at are independently H or C 1 -C 6  alkyl; or 
 wherein R 5  and R 6  and the nitrogen to which they are attached form a 5 or 6 membered heterocycloalkyl ring; and 
 
 wherein R 7  and R 8  are independently selected from —H; —C 1 -C 4  alkyl optionally substituted with 1, 2, or 3 groups independently selected from —OH, —NH 2 , and halogen; —C 3 -C 6  cycloalkyl; —(C 1 -C 4  alkyl)-O—(C 1 -C 4  alkyl). 
   
     
     
         6 . A compound according to  claim 5 , wherein R 1  is —CH 2 -phenyl where the phenyl ring is optionally substituted with 1 or 2 groups independently selected from halogen, C 1 -C 2  alkyl, C 1 -C 2  alkoxy and hydroxy. 
     
     
         7 . A compound according to  claim 6 , wherein R 1  is benzyl, 3-fluorobenzyl or 3,5-difluorobenzyl. 
     
     
         8 . A compound according to  claim 1 , wherein R 15  is H. 
     
     
         9 . A compound according to  claim 7 , wherein R 15  is H. 
     
     
         10 . A compound according to  claim 1  of the formula II: 
       
         
           
           
               
               
           
         
       
       wherein Z is hydrogen, —C 1 -C 6  alkyl, —C 2 -C 6  alkenyl, —C 2 -C 6  alkynyl or —C 3 -C 7  cycloalkyl, where each of said groups is optionally substituted with 1 or 2 R z  groups, wherein 1 or 2 methylene groups within said —C 1 -C 6  alkyl, —C 2 -C 6  alkenyl, —C 2 -C 6  alkynyl or —C 3 -C 7  cycloalkyl groups are optionally replaced with —(CO)—;
 wherein R z  at each occurrence is independently halogen, —OH, —CN, —CF 3 , C 1 -C 6  alkoxy, C 3 -C 7  cycloalkyl, C 3 -C 7  cycloalkoxy or —NR 100 R 101 ;
 where R 100  and R 101  are independently H, C 1 -C 6  alkyl, phenyl, CO(C 1 -C 6  alkyl) or SO 2 C 3 -C 6  alkyl; 
 
 
       wherein X is —C(═O)—; 
       wherein R 1  is C 1 -C 10  alkyl optionally substituted with 1 or 2 groups independently selected from halogen, —OH, ═O, —CN, —CF 3 , —OCF 3 , —C 3 -C 7  cycloalkyl, —C 1 -C 4  alkoxy, amino, mono-dialkylamino, aryl, heteroaryl or heterocycloalkyl, wherein the aryl group is optionally substituted with 1 or 2 R 50  groups;
 where R 50  is halogen, OH, CN, —CO—(C 1 -C 4  alkyl), —NR 7 R 8 , C 1 -C 6  alkyl, C 2 -C 6  alkenyl, C 2 -C 6  alkynyl, C 1 -C 6  alkoxy and C 3 -C 8  cycloalkyl;
 where R 7  and R 8  are selected from H; —C 1 -C 4  alkyl optionally substituted with 1, 2, or 3 groups selected from —OH, —NH 2  and halogen; —C 3 -C 6  cycloalkyl; —(C 1 -C 4  alkyl)-O—(C 1 -C 4  alkyl); —C 2 -C 4  alkenyl; and —C 2 -C 4  alkynyl; 
 
 
       wherein R c  is selected from aryl;
 —(CR 245 R 250 ) 0-4 -heteroaryl; 
 —(CR 245 R 250 ) 0-4 -heterocycloalkyl;
 where the aryl group attached to the —(CR 245 R 250 ) 0-4 — group is optionally substituted with 1, 2, 3 or 4 R 200  groups; 
 
 
       Where the heteroaryl group attached to the —(CR 245 R 250 ) 0-4 — group is optionally substituted with 1, 2, 3, or 4 R 200  groups; 
       where the heterocycloalkyl group attached to the —(CR 245 R 250 ) 0-4 — group is optionally substituted with 1, 2, 3, or 4 R 210  groups. 
     
     
         11 . A compound according to  claim 10 , wherein
 Z is —C 1 -C 6  alkyl;   R 1  is C 1 -C 10  alkyl substituted with 1 phenyl group, where the phenyl group attached to the alkyl is optionally substituted with 1 or 2 R 50  groups, where each R 50  is independently halogen, OH, CN, or C 1 -C 6  alkyl; and   R c  is —(CR 245 R 250 ) 0-4 -aryl or —(CR 245 R 250 ) 0-4 -heteroaryl, where the aryl and heteroaryl groups are optionally substituted with 1 or 2 R 200  groups.   
     
     
         12 . A compound according to  claim 1  which is
 N-[(1S,2R)-3-[(3-bromobenzyl)amino]-1-(3,5-difluorobenzyl)-2-hydroxypropyl]acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[(4R)-6-isopropyl-2,2-dioxido-3,4-dihydro-1H-isothiochromen-4-yl]amino}propyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[(4S)-6-isopropyl-2,2-dioxido-3,4-dihydro-1H-isothiochromen-4-yl]amino}propyl)acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(6-ethyl-2,2-dioxido-3,4-dihydro-1H-isothiochromen-4-yl)amino]-2-hydroxypropyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(6-ethyl-2,2-dioxido-3,4-dihydro-1H-isothiochromen-4-yl)amino]-2-hydroxypropyl}acetamide;   N-[(1S,2R)-3-{[1-(3-bromophenyl)cyclopropyl]amino}-1-(3,5-difluorobenzyl)-2-hydroxypropyl]acetamide hydrochloride;   methyl 3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-(3-bromophenyl)propanoate;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(3-ethylbenzyl)amino]-2-hydroxypropyl}acetamide;   methyl 3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-(3-ethylphenyl)propanoate;   3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-(3-ethylphenyl)propanoic acid;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[1-(3-ethylphenyl)-3-hydroxypropyl]amino}-2-hydroxypropyl)acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-[(1S)-1,2,3,4-tetrahydronaphthalen-1-ylamino]propyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(2,2-dioxido-3,4-dihydro-1H-isothiochromen-4-yl)amino]-2-hydroxypropyl}acetamide;   N-[1-(3,5-Difluoro-benzyl)-3-(6-ethyl-2,2-dioxo-2λ 6 -isothiochroman-4-ylamino)-2-hydroxy-propyl]-2-methylamino-acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-[(3-iodobenzyl)amino]propyl}acetamide;   methyl 3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-(3-iodophenyl)propanoate;   methyl 3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-[3-(3-hydroxyprop-1-ynyl)phenyl]propanoate;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[3-hydroxy-1-(3-iodophenyl)propyl]amino}propyl)acetamide;   methyl 3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-[3-(3-hydroxypropyl)phenyl]propanoate;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-[(7-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)amino]propyl}acetamide;   2-Amino-N-[1-(3,5-difluoro-benzyl)-3-(6-ethyl-2,2-dioxo-2λ 6 -isothiochroman-4-ylamino)-2-hydroxy-propyl]-acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[6-ethyl-2-(methylsulfonyl)-1,2,3,4-tetrahydroisoquinolin-4-yl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[(1S)-7-ethyl-1,2,3,4-tetrahydronaphthalen-1-yl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[(1R)-7-ethyl-1,2,3,4-tetrahydronaphthalen-1-yl]amino}-2-hydroxypropyl)acetamide;   N-[(1S,2R)-3-{[1-(3-bromophenyl)cyclopropyl]amino}-1-(3,5-difluorobenzyl)-2-hydroxypropyl]acetamide;   methyl 3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-[3-(5-formylthien-2-yl)phenyl]propanoate;   methyl 3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-(2′-acetyl-1,1′-biphenyl-3-yl)propanoate;   N-[1-(3,5-Difluoro-benzyl)-3-(6-ethyl-2,2-dioxo-2λ 6 -isothiochroman-4-ylamino)-2-hydroxy-propyl]-3-methyl-butyramide;   N-[(1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-({1-[3′-(hydroxymethyl)-1,1′-biphenyl-3-yl]cyclopropyl}amino)propyl]acetamide;   N-[(1S,2R)-1-(3,5-difluorobenzyl)-3-({1-[3-(5-formylthien-2-yl)phenyl]cyclopropyl}amino)-2-hydroxypropyl]acetamide;   N-[(1S,2R)-1-(3,5-difluorobenzyl)-3-(9H-fluoren-9-ylamino)-2-hydroxypropyl]acetamide;   methyl 3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-[3-(trifluoromethyl)phenyl]propanoate;   methyl 3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-(3-cyanophenyl)propanoate;   N-[1-(3,5-Difluoro-benzyl)-3-(6-ethyl-2,2-dioxo-2λ 6 -isothiochroman-4-ylamino)-2-hydroxy-propyl]-3-hydroxy-2,2-dimethyl-propionamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[1-(3-ethylphenyl)cyclopropyl]amino}-2-hydroxypropyl)acetamide;   methyl 3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-(3-bromophenyl)propanoate;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[1-(3-ethynylphenyl)cyclopropyl]amino}-2-hydroxypropyl)acetamide;   N-[(1S,2R)-3-[(2-bromo-9H-fluoren-9-yl)amino]-1-(3,5-difluorobenzyl)-2-hydroxypropyl]acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(2-ethyl-9H-fluoren-9-yl)amino]-2-hydroxypropyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(2,2-dioxido-3,4-dihydro-1,2-benzoxathiin-4-yl)amino]-2-hydroxypropyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-[((6-iodo-3,4-dihydro-2H-chromen-4-yl)amino]propyl}acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[(4S)-6-iodo-3,4-dihydro-2H-chromen-4-yl]amino}propyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[(4R)-6-iodo-3,4-dihydro-2H-chromen-4-yl]amino}propyl)acetamide;   N-[1-(3,5-Difluoro-benzyl)-3-(6-ethyl-2,2-dioxo-2λ 6 -isothiochroman-4-ylamino)-2-hydroxy-propyl]-3-hydroxy-propionamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(6-ethyl-2,2-dioxido-3,4-dihydro-1,2-benzoxathiin-4-yl)amino]-2-hydroxypropyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(6-ethyl-2,2-dioxido-3,4-dihydro-1,2-benzoxathiin-4-yl)amino]-2-hydroxypropyl}acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[4-(3-ethylphenyl)tetrahydro-2H-pyran-4-yl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[1-(3-ethylphenyl)butyl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[(4S)-6-ethyl-3,4-dihydro-2H-chromen-4-yl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[(4R)-6-ethyl-3,4-dihydro-2H-chromen-4-yl]amino}-2-hydroxypropyl)acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(7-ethyl-1,2,3,4-tetrahydronaphthalen-1-yl)amino]-2-hydroxypropyl}acetamide;   N-[1-(3,5-Difluoro-benzyl)-3-(6-ethyl-2,2-dioxo-2λ 6 -isothiochroman-4-ylamino)-2-hydroxy-propyl]-3-hydroxy-butyramide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[1-(3-ethylphenyl)cyclohexyl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[1-(3-ethylphenyl)cyclopentyl]amino}-2-hydroxypropyl)acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(6-ethyl-3,4-dihydro-1H-isothiochromen-4-yl)amino]-2-hydroxypropyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(2-ethyl-5-fluoro-9H-fluoren-9-yl)amino]-2-hydroxypropyl}acetamide;   methyl (3S)-3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-(3-ethylphenyl)butanoate;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[1-(3-isobutylisoxazol-5-yl)cyclopropyl]amino}propyl)acetamide;   N-[1-(3,5-Difluoro-benzyl)-3-(6-ethyl-2,2-dioxo-2λ 6 -isothiochroman-4-ylamino)-2-hydroxy-propyl]-2-phenyl-acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(2-ethyl-7-fluoro-9H-fluoren-9-yl)amino]-2-hydroxypropyl}acetamide;   methyl (3R)-3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-(3-ethylphenyl)butanoate;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(2,5-dipropylbenzyl)amino]-2-hydroxypropyl}acetamide;   {[1-(3,5-Difluoro-benzyl)-3-(6-ethyl-2,2-dioxo-2λ 6 -isothiochroman-4-ylamino)-2-hydroxy-propylcarbamoyl]-methyl}-methyl-carbamic acid tert-butyl ester;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-[(2-isobutyl-9H-fluoren-9-yl)amino]propyl}acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[(1S)-6-ethyl-2,3-dihydro-1H-inden-1-yl]amino}-2-hydroxypropyl)acetamide;   N-[1-(3,5-Difluoro-benzyl)-3-(6-ethyl-2,2-dioxo-2λ 6 -isothiochroman-4-ylamino)-2-hydroxy-propyl]-2-methyl-2-methylamino-propionamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[1-ethyl-1-(3-ethylphenyl)propyl]amino}-2-hydroxypropyl)acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(6-ethyl-2,2-dioxido-3,4-dihydro-1H-2,1-benzothiazin-4-yl)amino]-2-hydroxypropyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(6-ethyl-2,2-dioxido-3,4-dihydro-1H-2,1-benzothiazin-4-yl)amino]-2-hydroxypropyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(6-ethyl-3-methyl-2,2-dioxido-3,4-dihydro-1H-isothiochromen-4-yl)amino]-2-hydroxypropyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(6-ethyl-3-methyl-2,2-dioxido-3,4-dihydro-1H-isothiochromen-4-yl)amino]-2-hydroxypropyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(6-ethyl-1-methyl-1,2,3,4-tetrahydroquinolin-4-yl)amino]-2-hydroxypropyl}acetamide;   methyl 3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-(3-ethylphenyl)propanoate;   N-[1-(3,5-Difluoro-benzyl)-3-(6-ethyl-2,2-dioxo-2λ 6 -isothiochroman-4-ylamino)-2-hydroxy-propyl]-2-(1H-imidazol-4-yl)-acetamide;   methyl 3-{[(2R,3S)-3-(acetylamino)-4-(3,5-difluorophenyl)-2-hydroxybutyl]amino}-3-(3-ethylphenyl)propanoate;   N-[(1S,2R)-3-[(2-bromo-9-methyl-9H-fluoren-9-yl)amino]-1-(3,5-difluorobenzyl)-2-hydroxypropyl]acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[2-(1-ethylpropyl)-9H-fluoren-9-yl]amino}-2-hydroxypropyl)acetamide;   N-[(1S,2R)-3-[(2-cyclopentyl-9H-fluoren-9-yl)amino]-1-(3,5-difluorobenzyl)-2-hydroxypropyl]acetamide;   N-[1-(3,5-Difluoro-benzyl)-3-(6-ethyl-2,2-dioxo-2λ 6 -isothiochroman-4-ylamino)-2-hydroxy-propyl]-propionamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(2-ethyl-9-methyl-9H-fluoren-9-yl)amino]-2-hydroxypropyl}acetamide;   N-[(1S,2R)-3-[(2-cyclohexyl-9H-fluoren-9-yl)amino]-1-(3,5-difluorobenzyl)-2-hydroxypropyl]acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[1-(4-ethylpyridin-2-yl)cyclopropyl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[(4S)-6-(1H-pyrrol-3-yl)-3,4-dihydro-2H-chromen-4-yl]amino}propyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[(5R)-3-ethyl-6,7,8,9-tetrahydro-5H-benzo[7]annulen-5-yl]amino}-2-hydroxypropyl)acetamide;   N-[(1S,2R)-3-{[1-(3-bromophenyl)-1-methylethyl]amino}-1-(3,5-difluorobenzyl)-2-hydroxypropyl]acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[2-(dimethylamino)-9H-fluoren-9-yl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[(1S)-7-propyl-1,2,3,4-tetrahydronaphthalen-1-yl]amino}propyl)acetamide;   N-[(1S,2R)-1-(3,5-difluorobenzyl)-3-({(1S)-7-[(dimethylamino)methyl]-1,2,3,4-tetrahydronaphthalen-1-yl}amino)-2-hydroxypropyl]acetamide;   N-[(1S,2R)-3-{[(1S)-7-bromo-1,2,3,4-tetrahydronaphthalen-1-yl]amino}-1-(3,5-difluorobenzyl)-2-hydroxypropyl]acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[1-(3-propylphenyl)cyclopropyl]amino}propyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[1-(3-ethylphenyl)cycloheptyl]amino}-2-hydroxypropyl)acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-[(6-isopropyl-3,4-dihydro-2H-chromen-4-yl)amino]propyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(6-ethyl-2-hydroxy-2,3-dihydro-1H-inden-1-yl)amino]-2-hydroxypropyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(2-ethyl-6-fluoro-9H-fluoren-9-yl)amino]-2-hydroxypropyl}acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[2-(methoxymethyl)-9H-fluoren-9-yl]amino}propyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[1-(3-ethylphenyl)-2-(5-methyl-1,3-oxazol-2-yl)ethyl]amino}-2-hydroxypropyl)acetamide hydrochloride;   N-[(1S,2R)-1-(3,5-difluorobenzyl)-3-(3,4-dihydro-2H-chromen-4-ylamino)-2-hydroxypropyl]acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[2-ethyl-5-(trifluoromethyl)-9H-fluoren-9-yl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[2-(3-methylbutyl)-9H-fluoren-9-yl]amino}propyl)acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-[(2-isopropyl-9H-fluoren-9-yl)amino]propyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-[(2-neopentyl-9H-fluoren-9-yl)amino]propyl}acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-[(2-isopropenyl-9H-fluoren-9-yl)amino]propyl}acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[1-(3-ethylphenyl)-1-methylethyl]amino}-2-hydroxypropyl)acetamide hydrochloride;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[(4S)-6-isobutyl-3,4-dihydro-2H-chromen-4-yl]amino}propyl)acetamide;   N-[(1S,2R)-3-{[(4S)-6-cyano-3,4-dihydro-2H-chromen-4-yl]amino}-1-(3,5-difluorobenzyl)-2-hydroxypropyl]acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[(4S)-6-neopentyl-3,4-dihydro-2H-chromen-4-yl]amino}propyl)acetamide;   N-{(1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-[(6-neopentyl-3,4-dihydro-2H-chromen-4-yl)amino]propyl}acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[2-(isopropylamino)-9H-fluoren-9-yl]amino}propyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[1-(3-isobutylphenyl)cyclopropyl]amino}propyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[(4-isobutyl-1,1′-biphenyl-2-yl)methyl]amino}propyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[7-(2,2-dimethylpropyl)-5-ethyl-1,2,3,4-tetrahydronaphthalen-1-yl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[(4R)-6-(2,2-dimethylpropyl)-3,4-dihydro-2H-chromen-4-yl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[(1S)-7-(2,2-dimethylpropyl)-1,2,3,4-tetrahydronaphthalen-1-yl]amino}-2-hydroxypropyl)acetamide;   N-[(1S,2R)-3-{[1-(3-tert-butylphenyl)cyclohexyl]amino}-1-(3,5-difluorobenzyl)-2-hydroxypropyl]acetamide;   N-[(1S,2R)-3-{[4-(3-tert-butylphenyl)tetrahydro-2H-pyran-4-yl]amino}-1-(3,5-difluorobenzyl)-2-hydroxypropyl]acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[6-(2,2-dimethylpropyl)-1,2,3,4-tetrahydroquinolin-4-yl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[1-(3-isopropylphenyl)-4-oxocyclohexyl]amino}propyl)acetamide;   N-[(1S,2R)-3-{[(4S)-6-(2,2-dimethylpropyl)-3,4-dihydro-2H-chromen-4-yl]amino}-1-(3-fluorobenzyl)-2-hydroxypropyl]acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[5-(2,2-dimethylpropyl)-2-(1H-imidazol-1-yl)benzyl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[7-(2,2-dimethylpropyl)-1-methyl-1,2,3,4-tetrahydronaphthalen-1-yl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[(6-(2,2-dimethylpropyl)-4-methyl-3,4-dihydro-2H-chromen-4-yl]amino}-2-hydroxypropyl)acetamide;   N-((1S,2R)-1-(3-fluoro-4-hydroxybenzyl)-2-hydroxy-3-{[1-(3-isopropylphenyl)cyclohexyl]amino}propyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[1-(3-isopropylphenyl)cyclohexyl]amino}propyl)-2-fluoroacetamide;   N-((1S,2R)-1-[3-(allyloxy)-5-fluorobenzyl]-2-hydroxy-3-{[1-(3-isopropylphenyl)cyclohexyl]amino}propyl)acetamide;   N-[(1S,2R)-1-(3,5-difluorobenzyl)-3-({1-[3-(2,2-dimethylpropyl)phenyl]-1-methylethyl}amino)-2-hydroxypropyl]-2-fluoroacetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[(1S)-7-(2,2-dimethylpropyl)-1,2,3,4-tetrahydronaphthalen-1-yl]amino}-2-hydroxypropyl)-2-fluoroacetamide;   N-[(1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-({1-[3-(3-thienyl)phenyl]cyclohexyl}amino)propyl]acetamide;   N-[(1S,2R)-1-(3,5-difluorobenzyl)-3-({1-[4-(2,2-dimethylpropyl)pyridin-2-yl]cyclopropyl}amino)-2-hydroxypropyl]acetamide;   N-((1R,2S)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{[(1S)-7-propyl-1,2,3,4-tetrahydronaphthalen-1-yl]amino}propyl)acetamide;   N-((1S,2R)-1-(3,5-difluorobenzyl)-2-hydroxy-3-{([1-(3-isobutylphenyl)cyclohexyl]amino}propyl)acetamide;   N-((1S,2R)-2-hydroxy-1-(4-hydroxybenzyl)-3-{[1-(3-isopropylphenyl)cyclohexyl]amino}propyl)acetamide;   N-((1R,2S)-1-(3,5-difluorobenzyl)-3-{[(1S)-7-ethyl-1,2,3,4-tetrahydronaphthalen-1-yl]amino}-2-hydroxypropyl)-2-ethoxyacetamide; or   N-((1S,2R)-1-(3,5-difluorobenzyl)-3-{[(1R)-7-ethyl-1,2,3,4-tetrahydronaphthalen-1-yl]amino}-2-hydroxypropyl)-2,2-difluoroacetamide; or a pharmaceutically acceptable salt thereof.   
     
     
         13 . A method for preparing a compound of the formula 
       
         
           
           
               
               
           
         
       
       or a pharmaceutically acceptable salt thereof, wherein Z, X, R 1 , R 2 , R 3 , R 15  and R c  are as defined in  claim 1 . 
     
     
         14 . The method of treating a subject who has, or in preventing a subject from developing Alzheimer's disease (AD); preventing or delaying the onset of Alzheimer's disease; treating subjects with mild cognitive impairment (MCI); preventing or delaying the onset of Alzheimer's disease in subjects who would progress from MCI to AD; treating Down's syndrome; treating subjects who have Hereditary Cerebral Hemorrhage with Amyloidosis of the Dutch-Type; treating cerebral amyloid angiopathy and preventing its potential consequences; treating other degenerative dementias; treating dementia associated with Parkinson's disease, progressive supranuclear palsy, or cortical basal degeneration; treating diffuse Lewy body type AD; and treating frontotemporal dementias with parkinsonism (FTDP), comprising administering a pharmaceutically acceptable amount of a compound according to  claim 1  to a patient in need of such treatment.