Spiro compounds and methods of use

A Spiro compound of formula I

• Wherein
• a is 1, 2, 3, 4 or 5;
• b and c are each independently 1, 2, or 3;
• When X and Y are selected from (i) X combines Y to be an oxygen or methylene, (ii) X is hydrogen, Y is hydrogen, (iii) X is hydrogen, Y is hydroxy or its optical isomer;
• R′ and R″ are not presented;
• When X and Y are selected from (iv) X is hydrogen, Y is O, S or its optical isomer position, (v) X and Y are both O or S, or (vi) X is O and Y is S;
• R′ and R″ are each independently halogeno-lower alkyl, lower alkyl, lower alkoxy, hydroxy, lower alkylhydroxy;
• optionally R′ and R″ combine to form a 5 to 7 membered ring with X, Y and the spiro carbon which ring, may be unsubstituted or substituted independently by up to three substituents;
• R is selected from:
• Ra is selected from lower alkylenyl, lower alkenlenyl or lower alkynlenyl;
• Rb is selected from halogen, hydroxy, methanesulfonate, toluenesulfonate, aryl or heterocyclyl;
• W is selected from O, S, —NRc or —CHRc;
• G is selected from N, —C—CN or —CRc;
• Z is selected from O, S, —NRd or —CHRd;
• Rd c is selected from H, lower alkyl;
• Rd is selected from H, lower alkyl, amino or alkylamino;
• R1, R3, and R4 are each independently selected from H, halogen, halogeno-lower alkyl, lower alkyl, lower alkoxy, lower alkoxyalkoxy, lower alkenyl, or lower alkynyl;
• R2 is selected from H, halogen, halogeno-lower alkyl or lower alkyl;
• Or a pharmaceutically acceptable salt thereof.