| abstract |
A compound of ** formula ** or a pharmaceutically acceptable salt or solvate thereof, wherein: X1 is O or S; R1 is - (CH2) t ((4-10 link heterocycle), in which t is an integer from 0 to 5; said heterocyclic group is optionally condensed with a C6-C10 aryl group, a C5- saturated cyclic group C8 or a 5-10 link heterocyclic group; 1 or 2 carbon atoms in the preceding heterocyclic radicals are optionally substituted with an oxo radical (= O); the radicals - (CH2) t- of the preceding groups optionally include a double or triple carbon-carbon bond where t is an integer from 2 to 5; and the preceding R1 group, except H, are optionally substituted with 1 to 3 R4 groups; R2 is H. |