Piperidinetriol derivatives as inhibitors of glycosylceramidsynthase

1. A compound of formula (I) in free or pharmaceutically acceptable salt form:

wherein

R is —C 1-3 alkylAr 1 where Ar 1 is phenyl;

wherein phenyl is substituted by one or more substituents selected from CN, CON(R 1 ) 2 , SO n R 2 , SO 2 N(R 1 ) 2 , N(R 5 ) 2 , N(R 1 )COR 2 , N(R 1 )SO n R 2 , C 0-6 alkylAr 2 , C 2-6 alkenylAr 2 and C 3-6 alkynylAr 2 wherein one or more of the —CH 2 — groups of the alkyl chain may be replaced with a heteroatom selected from O, S and NR 3 , provided that when the heteroatom is O, at least two —CH 2 — groups separate it from any additional O atom in the alkyl chain; or two adjacent substituents on the Ar 1 phenyl may together form a fused 5- or 6-membered saturated or unsaturated ring wherein the ring optionally contains 1 or 2 heteroatoms selected from O, S and NR 4 and is optionally substituted by one or more substituents selected from, an oxo group, C 1-6 alkyl and C 0-3 alkylAr 4 ;

and the Ar 1 phenyl is optionally substituted by one or more additional substituents selected from F, Cl, Br, CF 3 , OCF 3 , OR 3 and C 1-6 alkyl;

R 1 is H, C 1-6 alkyl optionally substituted by OH, Ar 3 , or C 1-6 alkylAr 3 , or the group N(R 1 ) 2 may form a 5- to 10-membered heterocyclic group optionally containing one or more additional heteroatoms selected from O, S and NR 3 and is optionally substituted by an oxo group;

R 2 is C 1-6 alkyl optionally substituted by OH, Ar 3 , or C 1-6 alkylAr 3 ;

R 3 is H, or C 1-6 alkyl;

R 4 is H, C 1-6 alkyl or C 0-3 alkylAr 4 ;

R 5 is H, C 1-6 alkyl optionally substituted by OH, Ar 3 , or C 1-6 alkylAr 3 , or the group N(R 5 ) 2 may form a 5- to 10-membered heterocylic group optionally containing one or more additional heteroatoms selected from O, S and NR 3 and is optionally substituted by an oxo group;

Ar 2 and Ar 3 are independently phenyl or a 5- to 10-membered heteroaryl group containing up to 3 heteroatoms selected from O, S and NR 3 , which may be optionally substituted by one or more substituents selected from F, Cl, Br, CN, CF 3 , OCF 3 , OR 3 and C 1-6 alkyl;

Ar 4 is phenyl or pyridyl either of which may be optionally substituted by one or more substituents selected from F, Cl, Br, CN, CF 3 , OCF 3 , OR 3 and C 1-6 alkyl;

and n=0, 1 or 2.

2. The compound as defined in claim 1 wherein R is C 1 alkylAr 1 .

3. The compound as defined in claim 1 , wherein Ar 1 is phenyl, wherein phenyl is substituted as defined in claim 1 .

4. The compound as defined in claim 1 , wherein Ar 1 is phenyl, wherein phenyl is substituted by one or more substituents selected from CN, CON(R 1 ) 2 , N(R 5 ) 2 , and C 0-6 alkylAr 2 wherein one or more of the —CH 2 — groups of the alkyl chain may be replaced with a heteroatom selected from O, S and NR 3 , provided that when the heteroatom is O, at least two —CH 2 — groups separate it from any additional O atom in the alkyl chain, or two adjacent substituents on the Ar 1 phenyl may together form a fused 5- or 6-membered saturated or unsaturated ring wherein the ring optionally contains 1 or 2 heteroatoms selected from O and NR 4 and is optionally substituted by one or more substituents selected from, an oxo group, C 1-6 alkyl and C 0-3 alkylAr 4 , and the Ar 1 phenyl is optionally substituted by one or more additional substituents selected from F, Cl, Br, CF 3 , OCF 3 , OR 3 and C 1-6 alkyl.

5. The compound as defined in claim 1 , wherein Ar 1 is phenyl, wherein phenyl is substituted by one or more substituents selected from CN, CON(R 1 ) 2 , N(R 5 ) 2 , and C 0-6 alkylAr 2 wherein one or more of the —CH 2 — groups of the alkyl chain may be replaced with O, provided that at least two —CH 2 —groups separate it from any additional O atom introduced into the alkyl chain and the Ar 1 phenyl is optionally substituted by one or more additional substituents selected from F, Cl, Br, CF 3 , OCF 3 , OR 3 and C 1-6 alkyl.

6. The compound as defined in claim 1 , wherein Ar 2 is phenyl which is optionally substituted by one or more substituents selected from F, Cl, Br, CN, CF 3 , OCF 3 , OR 3 and C 1-6 alkyl.

7. The compound as defined in claim 1 , wherein R 1 is H or C 1-6 alkylAr 3 .

8. The compound as defined in claim 1 , wherein R 4 is H or C 1-6 alkyl.

9. The compound as defined in claim 1 , wherein Ar 3 is phenyl which may be optionally substituted by one or more substituents selected from F, Cl, Br, CN, CF 3 , OCF 3 , OR 3 and C 1-6 alkyl.

10. The compound as defined in claim 1 wherein R 5 is C 1-6 alkyl.

11. The compound selected from

Benzamide, N-[(4-fluorophenyl)methyl]-4-[[2S,3S,4R,5S)-3,4,5-trihydroxy-2-(hydroxymethyl)-1-piperidinyl]methyl]-;

3,4,5-Piperidinetriol, 2-(hydroxymethyl)-1-[[4-(phenylmethoxy)phenyl]methyl]-,(2S,3S,4R,5S);

Benzamide, N-[1-(S)-(phenyl)ethyl]-4-[[(2S,3S,4R,5S)-3,4,5-trihydroxy-2-(hydroxymethyl)-1-piperidinyl]methyl]-;

3,4,5-Piperidinetriol, 1-[(3-cyano-4-(dipropylamino)phenyl)methyl]-2-(hydroxymethyl)-, (2S,3S,4R,5S);

Benzamide, N-[1-(S)-(4-fluorophenyl)ethyl]-4-[[2S,3S,4R,5S)-3,4,5-trihydroxy-2-(hydroxymethyl)-1-piperidinyl]methyl]-;

Benzamide, N-[1-(R)-(phenyl)ethyl]-4-[[2S,3S,4R,5S)-3,4,5-trihydroxy-2-(hydroxymethyl)-1-piperidinyl]methyl]-;

Benzamide, N-[1-(R)-(4-fluorophenyl)ethyl]-4-[[2S,3S,4R,5S)-3,4,5-trihydroxy-2-(hydroxymethyl)-1-piperidinyl]methyl]-;

3,4,5-Piperidinetriol, 2-(hydroxymethyl)-1-[(2-phenyl-2H-1,4-benzoxazin-3(4H)-one-6-yl)methyl]-, (2S,3S,4R,5S);

3,4,5-Piperidinetriol, 2-(hydroxymethyl)-1-[[4-[(4-chlorophenyl)methoxy]phenyl]methyl]-, (2S,3S,4R,5S);

3,4,5-Piperidinetriol, 2-(hydroxymethyl)-1-[[4-[(4-fluorophenyl)methoxy]phenyl]methyl]-, (2S,3S,4R,5S), in free or pharmaceutically acceptable salt form.

12. The pharmaceutical composition comprising a compound of formula (I) as defined in claim 1 , together with one or more pharmaceutically acceptable carriers, excipients and/or diluents.

13. The process for the preparation of a compound of formula (I) as defined in claim 1 , the process comprising:

a) reductive amination of an aldehyde of formula R 5 CHO wherein R 5 is C 0-2 alkylAr 1 where Ar 1 is as defined in claim 1 , with a compound of formula (II):

or

b) deprotection of a compound of formula (III):

wherein R is as defined in claim 1 and P, which may be the same or different, are hydroxy protecting groups.