Phenylthioacetate compounds, compositions and methods of use

A compound of formula (I):

• wherein:
• each R1, R2, R3 and R4 is selected from H, halogen, —CN, C1 to C6 alkyl, C1 to C6 alkoxy, C3 to C7 cycloalkyl or a C-attached heterocycle;
• Ra and Rb are selected from H, halogen, C1 to C6 alkyl;
• or Ra and Rb, together with the carbon atom to which they are attached, form a 3-, 4-, 5- or 6-membered ring, optionally containing one or two heteroatoms selected from O, N and S;
• M is H, C1 to C4 alkyl or a pharmaceutically acceptable cation;
• W is CRw;
• wherein Rw is H, CN, CF3, CH3, OCH3, F or Cl;
• X is CRx;
• wherein Rx is H, halogen, —CN, C1 to C6 alkyl, C1 to C6 alkoxy, C3 to C7 cycloalkyl, —OH, —SH, —S(C1 to C6 alkyl), CH2OH, COORx′, CONHRx′ or SO2NH2;
• wherein Rx′ is H, or C1 to C6 alkyl;
• Ry is H, halogen, —CN, C1 to C6 alkyl, C1 to C6 alkoxy;
• Rz is H, halogen, —CN, C1 to C6 alkyl, C1 to C6 alkoxy;
• provided that at least one of R1, R2, R3, R4, Rw, Rx, Ry or Rz is not H;
• provided that if R2 is Cl, then Rx is not SEt;
• and
• provided that if R2 is Cl, then Rw is not CN.