| abstract |
The present invention relates to compounds of formula I and their pharmaceutically acceptable salts, solvates and hydrolysable esters.n n n (I)n n n n n n n n In this formula,n n n X 1 represents O or S, R 1 and R 2 independently represent H, halogen, -CH 3 and -OCH 3 , n represents 1 or 2, X 2 represents NH, NCH 3 or O , one of Y and Z is N, the other is O or S, R 3 is phenyl or pyridyl represents (where, N is located in the 2 or 3 position), optionally one or more halogen, NO 2, NH 2 , CF 3 , OCF 3 , OC 1-6 straight or branched chain alkyl, C 1-6 straight or branched chain alkyl, alkenyl or alkynyl, provided that when R 3 is pyridyl, R 4 represents CF 3 or CH 3 . |