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US 2026/0085042 A1Published application
Method for preparing indigo or a substituted derivative thereof
OwnerFilipe GOMES, Océane CHEVRON +5inventors
InventorsFilipe GOMES, Océane CHEVRON, Kevin COTTET, Guillaume BOISSONNAT, Debora VILONA, Cyril BOSSET, Vivien HENRYON
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Abstract
A method for the synthesis of dyes is described. More particularly, a method is described for preparing indigo, optionally substituted, that includes reacting anthranilic acid, optionally substituted, with glyoxylic acid under hydrogenation in the presence of a metal catalyst in a solvent, to obtain 2-(carboxymethylamino)benzoic acid, optionally substituted, and conversion of the latter to indigo, optionally substituted.
Claims21
A method of preparing a compound of formula (III):
- in which each of R1, R2, R3 and R4 is independently a hydrogen, a halogen, —CN, —NO2, —C(O)H, —SO3H, —CO2H, —SO3−M1+, —CO2−M2+, —SO3R5, —CO2R6, —C(O)R7 or —OR8,
- each of M1+ and M2+ being independently a cation,
- each of R5, R6, R7, and R8 being independently a C1-C6 aliphatic group or an aryl;
- the method comprising the following steps:
- a) reacting a compound of formula (I):
- in which each of R1, R2, R3 and R4 is as defined above,
- with glyoxylic acid under hydrogenation in the presence of a metal catalyst in a solvent, to obtain a compound of formula (II):
- in which each of R1, R2, R3 and R4 is as defined above;
- b) converting the compound of formula (II) to the compound of formula (III);
- and
- c) recovering the compound of formula (III).
8 more elements
Dependencies are inferred from the claim text.