| Verifiedfields | changed |
|---|---|
| Watchedfields | changed |
| Verifiedrevid | 436687870 |
| Pin | [2(2′)E]-3H,3′H-[2,2′-Bi-1-benzothiophenylidene]-3,3′-dione |
| Othernames | DyStar, C.I. Vat Red 41, C.I. 73 300 |
Thioindigo is an organosulfur compound that is used to dye polyester fabric. A synthetic dye, thioindigo is related to the plant-derived dye indigo, replacing two NH groups with two sulfur atoms to create a shade of pink.
Thioindigo is generated by the alkylation of the sulfur in thiosalicylic acid with chloroacetic acid. The resulting thioether cyclizes to 2-hydroxythianaphthene, which is easily converted to thioindigo.[1] The related compound 4,7,4',7'-tetrachlorothioindigo, also a commercially important dye (Pigment Red 88), can be prepared by chlorination of thioindigo.
References
- ^ Elmar Steingruber "Indigo and Indigo Colorants" in Ullmann's Encyclopedia of Industrial Chemistry, 2004, Wiley-VCH, Weinheim. doi:10.1002/14356007.a14_149.pub2