Derivatives of ppd useful for coloring hair and skin

A method of dyeing hair or of applying a temporary tattoo, which method comprises applying a composition comprising a compound of formula I or a physiologically acceptable salt or solvate, or an oxidised derivative thereof, to the hair or skin of a subject, wherein the compound of formula I has the structure:

• wherein:
• R1 and R2 independently represent H or C5-10 alkyl, which latter group is unsubstituted or substituted with one or more substituents selected from:
• C1-10 alkyl, which group is unsubstituted or substituted by one or more substituents selected from OH, nitro, CN, OR4, NR4bR4c, aryl and Het1;
• Cy1, which Cy1 group is unsubstituted or substituted by one or more substituents selected from nitro, CN, C1-6 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from OH, ═O, C1-4 alkyl and C1-4 alkoxy), and OR5a, S(O)qR5b, S(O)2NR5cR5d, NR5eS(O)2R5f, NR5gR5h;
• Heta, which Heta group is unsubstituted or substituted by one or more substituents selected from nitro, CN, C1-6 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from OH, ═O, halo, C1-4 alkyl and C1-4 alkoxy), OR6a, S(O)qR6b, S(O)2NR6cR6d, NR6eS(O)2R6f, NR6gR6h;
• and
• OR7a, S(O)qR7b, S(O)2NR7cR7d, NR7eS(O)2R7f and NR7gR7h,
• R3 represents H, C1-10 alkyl, OC1-10 alkyl, C(O)OC1-10 alkyl or OC(O)C1-10 alkyl, which latter four groups are unsubstituted or substituted with one or more substituents selected from:
• C1-10 alkyl, which group is unsubstituted or substituted by one or more substituents selected from OH, nitro, CN, OR8a, NR8bR8c, aryl and Het2;
• Cy2, which Cy2 group is unsubstituted or substituted by one or more substituents selected from nitro, CN, C1-6 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from OH, ═O, C1-4 alkyl and C1-4 alkoxy), and OR9a, S(O)qR9b, S(O)2NR9cR9d, NR9eS(O)2R9f, NR9gR9h;
• Hetb, which Hetb group is unsubstituted or substituted by one or more substituents selected from nitro, CN, C1-6 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from OH, ═O, halo, C1-4 alkyl and C1-4 alkoxy), OR10a, S(O)qR10b, S(O)2NR10cR10d, NR10eS(O)2R10f, NR10gR10h;
• and
• OR11a, S(O)qR11b, S(O)2NR11cR11d, NR11eS(O)2R11f and NR11gR11h,
• Het1 and Het2 represent, independently at each occurrence, a 4- to 14-membered heterocyclic group containing one or more heteroatoms selected from O, S and N, which heterocyclic groups may comprise one, two or three rings and may be substituted by one or more substituents selected from OR12a and C1-10 alkyl, which latter group is unsubstituted;
• Cy1 and Cy2 represent, independently at each occurrence, a 3- to 6-membered aromatic, fully saturated or partially unsaturated carbocyclic ring;
• R4a to R4c, R5a to R5h, R6a to R6h, R7a to R7h, R8a to R8c, R9a to R9h, R10a to R10h, R11a to R11h, independently represent, at each occurrence, H, or C1-10 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from C1-6 alkyl, OR12b), or R5-7c and R5-7d, R9-11c and R9-11d, R5-7g and R5-7h, R9-11g and R9-11h represent, together with the nitrogen atom to which they are attached, a 3- to 14-membered heterocyclic ring that may be aromatic, fully saturated or partially unsaturated and which may additionally contain one or more heteroatoms selected from O, S and N, which heterocyclic ring is optionally substituted by one or more substituents selected from halo, nitro, CN, and C1-10 alkyl;
• Heta and Hetb independently represent 4- to 14-membered heterocyclic groups containing one or more heteroatoms selected from O, S and N;
• R12a-b independently represents, at each occurrence, H or C1-4 alkyl,
• n represents 0 to 4, or a physiologically acceptable salt or solvate, or an oxidised derivative thereof, provided that when R1 and R2 are H, and n is 0, R3 is not H.

A compound of formula II:

• wherein:
• R13 represents H or C6-10 alkyl, which latter group is unsubstituted or substituted with one or more substituents selected from:
• C1-10 alkyl, which group is unsubstituted or substituted by one or more substituents selected from OH, nitro, CN, OR15a, NR15bR15c, aryl and Het3;
• Cy3, which Cy3 group is unsubstituted or substituted by one or more substituents selected from nitro, CN, C1-6 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from OH, ═O, C1-4 alkyl and C1-4 alkoxy), and OR16a, S(O)qR16b, S(O)2NR16cR16d, NR16eS(O)2R16f, NR16gR16h;
• Hetc, which Hetc group is unsubstituted or substituted by one or more substituents selected from nitro, CN, C1-6 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from OH, ═O, halo, C1-4 alkyl and C1-4 alkoxy), OR17a, S(O)qR17b, S(O)2NR17cR17d, NR17eS(O)2R17f, NR17gR17h;
• and
• OR18a, S(O)qR18b, S(O)2NR18cR18d, NR18eS(O)2R18f and NR18gR18h,
• R14 represents H, C1-10 alkyl, OC1-10 alkyl, C(O)OC1-10 alkyl or OC(O)C1-10 alkyl, which latter four groups are unsubstituted or substituted with one or more substituents selected from:
• C1-10 alkyl, which group is unsubstituted or substituted by one or more substituents selected from OH, nitro, CN, OR19a, NR19bR19c, aryl and Het4;
• Cy4, which Cy4 group is unsubstituted or substituted by one or more substituents selected from nitro, CN, C1-6 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from OH, ═O, C1-4 alkyl and C1-4 alkoxy), and OR20a, S(O)qR20b, S(O)2NR20cR20d, NR20eS(O)2R20f, NR20gR20h;
• Hetd, which Hetd group is unsubstituted or substituted by one or more substituents selected from nitro, CN, C1-10 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from OH, ═O, halo, C1-4 alkyl and C1-4 alkoxy), OR21a, S(O)qR21b, S(O)2NR21cR21d, NR21eS(O)2R21f, NR21gR21h;
• and
• OR22a, S(O)qR22b, S(O)2NR22cR22d, NR22eS(O)2R22f and NR22gR22h,
• Het3 and Het4 represent, independently at each occurrence, a 4- to 14-membered heterocyclic group containing one or more heteroatoms selected from O, S and N, which heterocyclic groups may comprise one, two or three rings and may be substituted by one or more substituents selected from OR23a and C1-10 alkyl, which latter group is unsubstituted;
• Cy3 and Cy4 represent, independently at each occurrence, a 3- to 6-membered fully saturated or partially unsaturated carbocyclic ring;
• R15a to R15c, R16a to R16h, R17a to R17h, R18a to R18h, R19a to R19c, R20a to R20h, R21a to R21h, R22a to R22h, independently represent, at each occurrence, H, or C1-10 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from C1-6 alkyl, OR23b), or R16-18c and R16-18d, R20-22c and R20-22d, R16-18g and R16-18h, R20-22g and R20-22h represent, together with the nitrogen atom to which they are attached, a 3- to 14-membered heterocyclic ring that may be aromatic, fully saturated or partially unsaturated and which may additionally contain one or more heteroatoms selected from O, S and N, which heterocyclic ring is optionally substituted by one or more substituents selected from halo, nitro, CN, and C1-6 alkyl;
• Hetc and Hetd independently represent 4- to 14-membered heterocyclic groups containing one or more heteroatoms selected from O, S and N;
• R23a-b independently represents, at each occurrence, H or C1-4 alkyl, or an oxidised derivative thereof, provided that when R13 is H, R14 is not n-hexyl.

A method of dyeing hair or of applying a temporary tattoo, which method comprises applying a composition comprising a compound of formula II or a physiologically acceptable salt or solvate, or an oxidised derivative thereof, to the hair or skin of a subject, wherein the compound of formula II has the structure:

• wherein:
• R13 represents H or C6-10 alkyl, which latter group is unsubstituted or substituted with one or more substituents selected from:
• C1-10 alkyl, which group is unsubstituted or substituted by one or more substituents selected from OH, nitro, CN, OR15a, NR15bR15c, aryl and Het3;
• Cy3, which Cy3 group is unsubstituted or substituted by one or more substituents selected from nitro, CN, C1-6 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from OH, ═O, C1-4 alkyl and C1-4 alkoxy), and OR16a, S(O)qR16b, S(O)2NR16cR16d, NR16eS(O)2R16f, NR16gR16h;
• Hetc, which Hetc group is unsubstituted or substituted by one or more substituents selected from nitro, CN, C1-6 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from OH, ═O, halo, C1-4 alkyl and C1-4 alkoxy), OR17a, S(O)qR17b, S(O)2NR17cR17d, NR17eS(O)2R17f, NR17gR17h;
• and
• OR18a, S(O)qR18b, S(O)2NR18cR18d, NR18eS(O)2R18f and NR18gR18h,
• R14 represents H, C1-10 alkyl, OC1-10 alkyl, C(O)OC1-10 alkyl or OC(O)C1-10 alkyl, which latter four groups are unsubstituted or substituted with one or more substituents selected from:
• C1-10 alkyl (which group is unsubstituted or substituted by one or more substituents selected from OH, nitro, CN, OR19a, NR19bR19c, aryl and Het4);
• Cy4 (which Cy4 group is unsubstituted or substituted by one or more substituents selected from nitro, CN, C1-6 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from OH, ═O, C1-4 alkyl and C1-4 alkoxy), and OR20a, S(O)qR20b, S(O)2NR20cR20d, NR20eS(O)2R20f, NR20gR20h);
• Hetd (which Hetd group is unsubstituted or substituted by one or more substituents selected from nitro, CN, C1-10 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from OH, ═O, halo, C1-4 alkyl and C1-4 alkoxy), OR21a, S(O)qR21b, S(O)2NR21cR21d, NR21eS(O)2R21f, NR21gR21h);
• and
• OR22a, S(O)qR22b, S(O)2NR22cR22d, NR22eS(O)2R22f and NR22gR22h,
• Het3 and Het4 represent, independently at each occurrence, a 4- to 14-membered heterocyclic group containing one or more heteroatoms selected from O, S and N, which heterocyclic groups may comprise one, two or three rings and may be substituted by one or more substituents selected from OR23a and C1-10 alkyl, which latter group is unsubstituted;
• Cy3 and Cy4 represent, independently at each occurrence, a 3- to 6-membered fully saturated or partially unsaturated carbocyclic ring;
• R15a to R15c, R16a to R16h, R17a to R17h, R18a to R18h, R19a to R19c, R20a to R20h, R21a to R21h, R22a to R22h, independently represent, at each occurrence, H, or C1-10 alkyl (which latter group is unsubstituted or substituted by one or more substituents selected from C1-6 alkyl, OR23b), or R16-18c and R16-18d, R20-22c and R20-22d, R16-18g and R16-18h, R20-22g and R20-22h represent, together with the nitrogen atom to which they are attached, a 3- to 14-membered heterocyclic ring that may be aromatic, fully saturated or partially unsaturated and which may additionally contain one or more heteroatoms selected from O, S and N, which heterocyclic ring is optionally substituted by one or more substituents selected from halo, nitro, CN, and C1-6 alkyl;
• Hetc and Hetd independently represent 4- to 14-membered heterocyclic groups containing one or more heteroatoms selected from O, S and N;
• R23a-b independently represents, at each occurrence, H or C1-4 alkyl, or an oxidised derivative thereof.