Patent ID: 8829184

Claim:
A compound of formula I: wherein: R 7 and R 8 are independently selected from: OR A , where R A is selected from C 1-4 saturated alkyl, optionally substituted by phenyl, which may bear a chloro substituent, pyridyl and furanyl; chloro; NH 2 ; —CH 2 —O—C(═O)Me; or R 7 and R 8 together form a group —O—(CH 2 ) m —O—, where m is 1 or 2; or the compound is a dimer with each monomer independently being of formula (I), where the R 7 groups or R 8 groups of each monomer form together a dimer bridge having the formula —X—R″—X— linking the monomers, where R″ is a C 3-12 saturated alkylene group, which group may be interrupted by O, S, NH, NMe, phenylene or pyridylene, where the phenylene and pyridylene groups are optionally substituted by NH 2 , and each X is independently selected from O, S, or NH; R 9 is selected from H, methyl and methoxy; R s is selected from CF 3 , (CF 2 ) 3 CF 3 , CH 3 and and R C is selected: (i) —C(═O)—OR c1 , where R C1 is a saturated C 1-4 alkyl group; (ii) —CH 2 —O—C(═O)R c2 , where R C2 is methyl or phenyl; (iii) —CH 2 —O—Si—(R Si1 )(R Si2 )(R Si3 )where R Si1 , R Si2 , R Si3 are independently selected from C 1-6 a saturated alkyl group and a phenyl group; and (iv) —C(—YR C3 )(—YR C4 ) where each Y is independently O or S, and where R C3 and R C4 are independently a saturated C 1-4 alkyl group, or together form a C 2-3 alkylene, which is substantially free of any of the corresponding compound of formula IB: