Patent ID: 8524916

Claim:
A compound of formula (I) in which X 1 is O or S, X 2 is O or S, X 3 is O or S, R 1 and R 2 are the same or different and are each hydrogen, C 1 -C 8 -alkyl which is optionally substituted with one or more halogen, OR 3 , or COR 4 , C 3 -C 7 -cycloalkyl which is optionally substituted with one ore more halogen, C 1 -C 4 -alkyl, or C 1 -C 4 -haloalkyl, or are aryl or aryl-(C 1 -C 4 -alkyl) which in each case is optionally substituted with one or more halogen, C 1 -C 4 -alkyl, C 1 -C 4 -haloalkyl, COR 4 , or sulphonylamino, R 3 is hydrogen, C 1 -C 4 -alkyl, C 1 -C 4 -alkylcarbonyl or aryl which is optionally substituted with one or more halogen, C 1 -C 4 -alkyl, or C 1 -C 4 -haloalkyl, R 4 is hydroxyl, C 1 -C 4 -alkyl or C 1 -C 4 -alkoxy, and salts thereof.