| abstract |
Compound of Formula (I): X represents O or S; R 1 represents C 1-6 alkyl, C 3-8 cycloalkyl, C 3-8 cycloalkylmethyl or C 3-8 cycloalkenyl, any of which may be optionally substituted by one or more methyl groups or halogen atoms or R 1 represents aryl, substituted aryl, heteroaryl or substituted heteroaryl; R 2 represents hydrogen, methyl, which may be in either a or B configurations or methylene; R 3 and R 4 are the same or different and each independently represents hydrogen, halogen or a methyl group; and ......... represents a single or a double bond; or a physiologically acceptable salt or solvate thereof. |