This disclosure pertains generally to the field of chemical synthesis and purification, and more specifically to methods of synthesizing and purifying certain 3,7 diamino-phenothiazin-5-ium compounds (referred to herein as diaminophenothiaziniumcompounds) including Methythioninium Chloride (MTC) (also known as Methylene Blue). In one embodiment, the method comprises the steps of, in order: nitrosylation (NOS); nitrosyl reduction (NR); thiosulfonic acid formation (TSAF); oxidative coupling (OC); Cr(VI) reduction (CR); isolation and purification of zwitterionic intermediate (IAPOZI); ring closure (RC); chloride salt-formation (CSF); one of: sulphide treatment (ST); dimethyldithiocarbamate treatment (DT); carbonate treatment (CT); ethylenediaminetetraacetic acid treatment (EDTAT); organic extraction (OE); and recrystallisation (RX). Also disclosed resulting (high purity) compounds, compositions comprising them (e.g., tablets, capsules), and their use in methods of inactivating pathogens, and methods of medical treatment and diagnosis, etc., for example, for tauopathies, Alzheimer's disease (AD), skin cancer, melanoma, viral diseases, bacterial diseases, or protozoal diseases.

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.

The present invention relates to: a process for preparing 3,7-bis-(dimethylamino)-phenothiazin-5-ium bromide or chloride; a method of converting 3,7-bis-(dimethylamino)-phenothiazin-5-ium bromide to 3,7-bis-(di-methylamino)-phenothiazin-5-ium chloride; and the purification of 7-bis-(di-methylamino)-phenothiazin-5-ium chloride by crystallization from aqueous solution of hydrochloric acid, leading to a pharmaceutically acceptable 3,7-bis-(di-methylamino)-phenothiazin-5-ium chloride (methylthioninium chloride, methylene blue, MTC) of formula I below reported.

##STR00001##

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.

The present disclosure provides phenothiazine derivative compounds and salts thereof, compositions comprising these compounds, and methods of using these compounds in a variety of applications, such as treatment or suppression of diseases associated with decreased mitochondrial function resulting in diminished ATP production and/or oxidative stress and/or lipid peroxidation.

The present disclosure provides phenothiazine derivative compounds and salts thereof, compositions comprising these compounds, and methods of using these compounds in a variety of applications, such as treatment or suppression of diseases associated with decreased mitochondrial function resulting in diminished ATP production and/or oxidative stress and/or lipid peroxidation.

Disclosed are methods of synthesis and/or purification of certain 3,7-diamino-phenothiazin-5-ium compounds (diaminophenothiazinium compounds) including Methylthioninium Chloride (MTC) (Methylene Blue), and the resulting high purity characterized by a purity greater than 98%, and very low levels of heavy metals and organic impurities Azure A, B, C and MVB. Also disclosed are methods of treatment of a tauopathy or methemoglobinemia in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of the high-purity diaminophenothiazinium compound.

Disclosed are methods of synthesis and/or purification of certain 3,7-diamino-phenothiazin-5-ium compounds (diaminophenothiazinium compounds) including Methylthioninium Chloride (MTC) (Methylene Blue), and the resulting high purity characterized by a purity greater than 98%, and very low levels of heavy metals and organic impurities Azure A, B, C and MVB. Also disclosed are methods of treatment of a tauopathy or methemoglobinemia in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of the high-purity diaminophenothiazinium compound.

Provided is a host material compound having a structure represented by Formula (I):

##STR00001## in which m and n, respectively representing the number of electron donors D and the number of electron acceptors A, are each 1, 2 or 3; p and q, respectively representing the number of the group L.sub.1 and the number of the group L.sub.2, are each 0, 1, or 2. D, L.sub.1 and L.sub.2 are each alkyl, cycloalkyl, heterocyclic group, aryl, heteroaryl, fused aryl, or fused heteroaryl; and A is selected from nitrogen-containing heterocyclic substituents, cyano-containing substituents, triaryl-boron-derived substituents, and phosphorus oxygen double bond-containing substituents. The compound has a D-()--()-A structure with bipolarity, and the bond can interrupt an intramolecular charge transfer between D and A, so that the excited state is limited to a local excited state in moiety of D or A, and the compound has a small excited-state dipole moment.

Provided is a host material compound having a structure represented by Formula (I):

##STR00001## in which m and n, respectively representing the number of electron donors D and the number of electron acceptors A, are each 1, 2 or 3; p and q, respectively representing the number of the group L.sub.1 and the number of the group L.sub.2, are each 0, 1, or 2. D, L.sub.1 and L.sub.2 are each alkyl, cycloalkyl, heterocyclic group, aryl, heteroaryl, fused aryl, or fused heteroaryl; and A is selected from nitrogen-containing heterocyclic substituents, cyano-containing substituents, triaryl-boron-derived substituents, and phosphorus oxygen double bond-containing substituents. The compound has a D-()--()-A structure with bipolarity, and the bond can interrupt an intramolecular charge transfer between D and A, so that the excited state is limited to a local excited state in moiety of D or A, and the compound has a small excited-state dipole moment.