A compound, wherein the compound is a compound of formula II: ** Formula ** or a pharmaceutically acceptable salt thereof, in which: R1 is an aliphatic C1-6 group, in which R1 is optionally substituted with up to 2 groups independently selected from -OR, -OR4 or -C1-3 haloalkyl； each R is independently hydrogen or aliphatic C1-6； each R2 is independently R, fluoro or chloro； m is 0, 1 or 2； R3 is hydrogen, C1-3 aliphatic, fluoro or chloro； each R4 is independently hydrogen, -C (R) 2O-R5 or R5, provided that at least one R4 or R8 group is not hydrogen； each R5 is independently -C (O) R6, -C (O) OR6, -C (O) -Q-R6, -C (O) - (CH2) nC (O) OR6, -C (O) - ( CH2) n- C (O) N (R7) 2, -C (O) - (CH2) n-CH (R6) N (R7) 2, -P (O) (OR6) 2； each R6 is independently hydrogen, an optionally substituted aliphatic C1-6 group or a saturated, partially unsaturated or fully unsaturated, optionally substituted 5-8 membered ring, having 0-4 heteroatoms independently selected from nitrogen, oxygen or sulfur； each R7 is independently hydrogen, -C (O) R6, -C (O) OR6, -S (O) 2R6, -OR6, an optionally substituted aliphatic C1-6 group or a saturated, partially unsaturated 5-8 membered ring or totally unsaturated, optionally substituted, which has 0-4 heteroatoms independently selected from nitrogen, oxygen or sulfur, or: two R6 in the same nitrogen atom taken together with the nitrogen atom to which they are attached form a ring of 4-7 saturated, partially unsaturated or fully unsaturated members having 1-3 heteroatoms in addition to the nitrogen atom, independently selected from nitrogen, oxygen or sulfur； each n is 0-6； Q is an optionally substituted C1-10 alkylidene chain in which zero to four methylene units of Q are independently replaced by -O-, -N (R) -, -S-, -S (O) -, -S ( O) 2- or - C (O) -； and R8 is hydrogen or -C (R) 2O-R5.Un compuesto, en el que el compuesto es un compuesto de fórmula II:**Fórmula** o una de sus sales farmacéuticamente aceptables, en la que: R1 es un grupo C1-6 alifátic
