| abstract |
1. The compound of formula I: or a pharmaceutically acceptable salt thereof, wherein: R is hydrogen or an optionally substituted Saliphatic group, or: R and a substituent on Ring A, taken together with their intermediate atoms, form an optionally substituted 5-7 membered partially unsaturated or an aromatic fused ring having 1-3 heteroatoms independently selected from nitrogen, oxygen or sulfur; X is —C (O) - or —S (O) -, L is a covalent bond or an optionally substituted divalent group, from C 1-6 alkylene, C 2-6 alkyleneylene or C 1-6 alkynylene, where one or more methylene units of L are optionally and independently replaced by -Cy-, -O-, -S-, -N (R) -, -C (O) -, -C (O) N (R) -, -N (R) C (O) N (R) -, -N (R) C (O) -, -N (R) C (O) O-, -OC (O) N (R) -, -S (O) -, -S (O) N (R) -, -N (R) S (O) -, -OC (O) -, or -C (O) O; Cy is optionally substituted bivalent ring selected from phenylene, 3-7 membered saturated or partially unsaturated carbocyclylene, 4-7 membered saturated or partially unsaturated heterocyclylene having 1-2 heteroatoms independently selected from nitrogen, oxygen or sulfur, or 5-6 heteroarylene having 1 to 3 heteroatoms independently selected from nitrogen, oxygen or sulfur; each R 1 is hydrogen or an optionally substituted Saliphatic group; A is a covalent bond or an optionally substituted bivalent ring selected from 3-7 membered saturated or partially unsaturated monocyclic carbocyclylene, 7-10 membered saturated or partially unsaturated bicyclic carbocyclylene; 4-7 membered saturated or partially unsaturated monocyclic heterocyclylene having 1-2 heteroato |