Abstract: Method for preparing 3,7-bis(dimethylamino)phenothiazin-5-ylium iodide, the method resulting in a high purity while being very simple to implement and producing high yields. The method uses phenothiazine as a starting material and includes the following steps: a) treating phenothiazine with diiodine, b) treating the reaction medium directly obtained from step a) with dimethylamine.

Abstract: A process for synthesizing a compound of formula (I) including: (a) condensing the benzaldehyde compound of formula (II) with the dialkylaniline of formula (III) to give the triphenylmethane of formula (IV); (b) treating the triphenylmethane of formula (IV) with sulfuric acid to form the triphenylmethane sulfone of the formula (V); and (c) oxidizing the triphenylmethane sulfone of formula (V) with a quinone. Such a process may be used to prepare patent blue.

Abstract: A process for preparing a compound of formula including oxidizing the triphenylmethane sulfone of formula (V) with a quinone chosen from 1,4-benzoquinone, 1,2-benzoquinone, a di(C1-C4)alkyl-1,4-benzoquinone, a di(C1-C4)alkyl-1,2-benzoquinone, a mono(C1-C4)alkyl-1,4-benzoquinone and a mono(C1-C4)alkyl-1,2-benzoquinone. A crystalline form of patent blue, sodium salt, can be achieved.

Abstract: Method for preparing 3,7-bis(dimethylamino)phenothiazin-5-ylium iodide, the method resulting in a high purity while being very simple to implement and producing high yields. The method uses phenothiazine as a starting material and includes the following steps: a) treating phenothiazine with diiodine, b) treating the reaction medium directly obtained from step a) with dimethylamine.

Abstract: Method for preparing 3,7-bis(dimethylamino)phenothiazin-5-ylium iodide, the method resulting in a high purity while being very simple to implement and producing high yields. The method uses phenothiazine as a starting material and includes the following steps: a) treating phenothiazine with diiodine, b) treating the reaction medium directly obtained from step a) with dimethylamine.

Abstract: Process for preparing disodium 5,5?-indigosulfonate, the feedstock being indigo, this process including the following steps: i) the indigo is subjected to a sulfonation treatment resulting in a mixture that contains 5,5?-indigosulfonic acid, this process including: ii) a reduction treatment is applied to the mixture obtained in step i), and optionally a purification step, so as to obtain a composition including leuco-5,5?-indigosulfonic acid, iii) the leuco-5,5?-indigosulfonic acid is isolated from the composition resulting from step ii), iv) the leuco-5,5?-indigosulfonic acid resulting from step iii) is oxidized to give disodium 5,5?-indigosulfonate.

Abstract: Process for preparing disodium 5,5?-indigosulfonate, the feedstock being indigo, this process including the following steps: i) the indigo is subjected to a sulfonation treatment resulting in a mixture that contains 5,5?-indigosulfonic acid, this process including: ii) a reduction treatment is applied to the mixture obtained in step i), and optionally a purification step, so as to obtain a composition including leuco-5,5?-indigosulfonic acid, iii) the leuco-5,5?-indigosulfonic acid is isolated from the composition resulting from step ii), iv) the leuco-5,5?-indigosulfonic acid resulting from step iii) is oxidized to give disodium 5,5?-indigosulfonate.

Abstract: Method for preparing 3,7-bis(dimethylamino)phenothiazin-5-ylium iodide, the method resulting in a high purity while being very simple to implement and producing high yields. The method uses phenothiazine as a starting material and includes the following steps: a) treating phenothiazine with diiodine, b) treating the reaction medium directly obtained from step a) with dimethylamine.

Abstract: Process for preparing disodium 5,5?-indigosulfonate, the feedstock being indigo, this process including the following steps: i) the indigo is subjected to a sulfonation treatment resulting in a mixture that contains 5,5?-indigosulfonic acid, this process including: ii) a reduction treatment is applied to the mixture obtained in step i), and optionally a purification step, so as to obtain a composition including leuco-5,5?-indigosulfonic acid, iii) the leuco-5,5?-indigosulfonic acid is isolated from the composition resulting from step ii), iv) the leuco-5,5?-indigosulfonic acid resulting from step iii) is oxidized to give disodium 5,5?-indigosulfonate.