MODIFIED DYE COMPOUNDS AND METHODS OF DYEING SUBSTRATES

1 . A dye compound for use in dyeing a substrate, the dye compound comprising a thio-indigo derivative, or a salt thereof, having one or more modification over the chemical structure of thio-indigo, wherein the thio-indigo derivative has a water-solubility of greater than 0.2% w/v in the absence of a reducing agent and in the presence oxygen, and converts to thio-indigo upon removing the modification, wherein the chemical structure of thioindigo is the following:

2 . The dye compound of claim 1 , wherein the dye compound is not thio-indigo.

3 . The dye compound of claim 1 , wherein the one or more modification enhances the aqueous solubility of the dye compound lacking the modification.

4 . The dye compound of claim 1 , wherein the one or more modification is a substituent on thio-indigo or the thio-indigo derivative.

5 . The dye compound of claim 4 , wherein the substituent is on one or more carbon atoms or on one more both oxygen atoms.

6 . The dye compound of claim 4 , wherein the substituent is an alkyl, cycloalkyl, alkoxy, halide, acyl, amine, ester, amide, aryl, heteroaryl, heterocyclyl, sulfonate, carbamate, urea, imine, oxime, anhydride, CN, NO 2 , mesylate, or tosylate, wherein each is optionally substituted.

7 . The compound of claim 1 which is of formula (I), (II), or (III):

wherein:

X 1 and X 2 are, independently, O, S, or Se;

Z 1 and Z 2 are, independently, NR 5 , S, Se, or O;

R 1 , R 2 , and R 5 are, independently, H, SO 3 R C , SO 2 R C , PO 3 (R C ) 2 , C(O)NR A R B , C(O)-(optionally substituted C 1-6 alkyl), C(O)-(optionally substituted aryl), C(O)-(optionally substituted C 1-9 glycolyl), C(O)-(optionally substituted C 1-6 hydroxyalkyl), C(O)-(optionally substituted heteroaryl), C(O)-(optionally substituted heterocyclyl), C(O)O-(optionally substituted C 1-6 alkyl), C(O)O-(optionally substituted aryl), C(O)O-(optionally substituted C 1-9 glycolyl), C(O)O-(optionally substituted C 1-6 hydroxyalkyl), C(O)O-(optionally substituted heteroaryl), or C(O)O-(optionally substituted heterocyclyl);

R A and R B are, independently, H or optionally substituted C 1-6 alkyl, or optionally substituted aryl;

R C is H, optionally substituted C 1-6 alkyl, optionally substituted C 3-8 cycloalkyl, optionally substituted aryl, optionally substituted heteroaryl, or optionally substituted heterocyclyl;

R 3 and R 4 are, independently, H, halide, optionally substituted C 1-6 alkyl, optionally substituted C 1-6 hydroxyalkyl, optionally substituted C 1-6 alkoxy, optionally substituted aryl, or SO 3 H;

m and n are, independently, 0 to 4;

wherein:

both X 1 and X 2 are not O when Z 1 and Z 2 are S;

both X 1 and X 2 are not O when Z 1 and Z 2 are NR;

both X1 is O, Z 1 is NH, X 2 is O, and Z 2 is S;

or a salt thereof.

8 . The compound of claim 1 , which is of formula (I-A), (I-B), or (I-C):

wherein:

R 3 and R 4 are, independently, H, halide, optionally substituted C 1-6 alkyl, optionally substituted C 1-6 hydroxyalkyl, optionally substituted C 1-6 alkoxy, optionally substituted aryl, or SO 3 H;

R 7 and R 8 are, independently, H, SO 3 R C , SO 2 R C , PO 3 (R C ) 2 , C(O)NR A R B , C(O)-(optionally substituted C 1-6 alkyl), C(O)-(optionally substituted aryl), C(O)-(optionally substituted C 1-9 glycolyl), C(O)-(optionally substituted C 1-6 hydroxyalkyl), C(O)-(optionally substituted heteroaryl), C(O)-(optionally substituted heterocyclyl), C(O)O-(optionally substituted C 1-6 alkyl), C(O)O-(optionally substituted aryl), C(O)O-(optionally substituted C 1-9 glycolyl), C(O)O-(optionally substituted C 1-6 hydroxyalkyl), C(O)O-(optionally substituted heteroaryl), or C(O)O-(optionally substituted heterocyclyl);

R A and R B are, independently, H or optionally substituted C 1-6 alkyl, or optionally substituted aryl;

R C is H, optionally substituted C 1-6 alkyl, optionally substituted C 3-8 cycloalkyl, optionally substituted aryl, optionally substituted heteroaryl, or optionally substituted heterocyclyl;

m and n are, independently, 0 to 4;

or a salt thereof.

9 . The compound of claim 8 which is of formula (II-A), (II-B), (II-C), (III-A), (III-B), (III-C), (IV-A), (IV-B), (IV-C), (V-A), (V-B), (V-C), (VI-A), (VI-B), (VI-C), (VII-A), (VII-B), (VII-C), (VIII-A), (VIII-B), (VIII-C), (IX-A), (IX-B), (IX-C), (X-A), (X-B), or (X-C), or a salt thereof:

10 . The compound of claim 1 , that is:

or a salt thereof.

11 . The compound of claim 1 , which converts to the leuco form of the compound through hydrolysis using a hydrolyzing agent, heat, steam, or a combination thereof.

12 . The compound of claim 12 , which has greater water solubility than the leuco form of the compound.

13 . A kit comprising:

(i) one or more compound of claim 1 ; and

(ii) a reagent and/or device that converts the compound to thio-indigo.

14 . A method of preparing a bath for dyeing a substrate, comprising mixing a compound of claim 1 with water.

15 . A method of dyeing a substrate, comprising:

(i) contacting the substrate with a compound of claim 1 ; and

(ii) hydrolyzing the compound of step (i); and

(iii) optionally rinsing the product of step (ii).

16 . The method of claim 15 , wherein the contacting comprises an aqueous bath having a pH less than about 9.

17 . The method of claim 16 , wherein the aqueous bath lacks an alkali agent or a reducing agent to convert the compound to a leuco form of the compound.

18 . The method of claim 17 , further comprising:

(iv) pretreating the substrate prior to step (i) with a cationic agent or caustic agent.

19 . The method of claim 17 , wherein the substrate is a textile.

20 . The method of claim 17 , wherein less than about 50 wt. % of the compound in an aqueous solution degrades under atmospheric conditions over a period of about 12 hours in the absence of a reducing agent.