There is provided a compound of Formula (I) wherein (I) R2 is selected from (i) an alkyloxyalkyl group (ii) a nitrile group, and wherein R2 is capable of forming a hydrogen bond (iii) alkylaryl group, wherein the aryl group is substituted by other than a C1-10 group (iv) alkenylaryl group wherein the aryl group is substituted (v) alkylheteroaryl group, wherein when heteroaryl group comprises only C and N in the ring, the aryl group is substituted by other than a methyl group (vi) alkenylheteroaryl group, (vii) ═N—O-alkyl or ═N—O—H group (viii) branched alkenyl (ix) alkyl-alcohol group (x) amide or alkylamide wherein (a) the alkyl of the alkylamide is —CH2— or —Ch2Ch2—, (b) the amide is di-substituted and/or (c) the amide is substituted with at least one of alkyl heterocycle group, alkenyl heterocycle group, alkylheteroaryl group, alkenylheteroaryl group, heteroaryl group, alkylamine group, alkyloxyalkyl group, alkylaryl group, straight or branched alkyl group, (xi) —CHO so that R1 together with R3 provide the enol tautomer (a); OR R2 together with R3 form (xii) a pyrazole wherein (a) R4 is ═N—O-alkyl or ═N—O—H group, (b) the pyrazole is substituted with one of alkyl-OH group, alkyl ester group, alkyloxyalkyl group, branched alkyl group, and an amide and/or (c) the 2 position is substituted with a group selected from —OH and —O-hydrocarbyl (xiii) a heteroaryl ring to provide a compound of the formula (b); (II) R2 is selected from groups capable of forming a hydrogen bond, a sulphamate group, a phosphonate group, a thiophosphonate group, a sulphonate group and a sulphonamide group; and (III) R3 is selected from —OH, ═O, or a C(═O)—mimetic.