Processes for preparing novel methylene blue derivative

• US 20050107607A1
• Filed: 11/17/2003
• Published: 05/19/2005
• Est. Priority Date: 06/17/2002
• Status: Active Grant

• Current Assignee: Verification Technologies, Inc. (Sun Chemical, Inc.)
• Original Assignee: Verification Technologies, Inc. (Sun Chemical, Inc.)
• Inventors: Miller, Peter, Cook, Ewell, Vig, Rakesh, Selinfreund, Richard H., Philips, Chris, Cunningham, Mike, Saglimbeni, Anthony A., Gerger, Scott
• Granted Patent: US 7,176,308 B2
• Time in Patent Office: Days
• US Class Current: 544/37
• CPC Class Codes: C07D 279/18 [b, e]-condensed with two six-membered rings

Abstract

Methods for the preparation of 7-(dipropylamino)pheno-thiazin-3-ylidene]-dipropylamine

Claims

1. A method for synthesizing [7-(dipropylamino)phenothiazin-3-ylidene]dipropylamine comprising the steps of:

(a) reacting phenothiazine with dipropyl amine in the presence of bromine;

(b) purifying the product of step (a).

2. A method of the synthesis of [7-(dipropylamino)pheno-thiazin-3-ylidene]dipropylamine comprising the step of reacting 3,7-dibromophenothiazine-5-ium bromide with dipropyl amine optionally in the presence of Copper.

3. A method for the synthesis of [7-(dipropylamino)pheno-thiazin-3-ylidene]dipropylamine comprising the steps of:

(a) acetylating the ring nitrogen of 3,7-dinitrophenothiazine;

(b) reducing the product of step (a);

(c) alkylating the product of step (b) with;

(c′

) propyl bromide and a base or (c″

) propyl aldehyde plus NaBH₃CN.

4. A method for isolating 7-(dipropylamino)pheno-thiazin-3-ylidene]dipropylamine from an impure mixture comprising the steps of:

(a) dissolving the impure mixture in hot water;

(b) filtering the hot solution of step (a) to remove insoluble matters;

(c) treating the hot filtrate of step (b) with ZnCl₂ to precipatate the ZnCl₂ salt;

(d) dissolving the ZnCl₂ salt in a base;

(e) washing the filtrate of step (d) with an organic solvent treating the same with a salt to precipitate 7-(dipropylamino)pheno-thiazin-3-ylidene]-dipropylamine.

5. A method for preparing 7-(dipropylamino)pheno-thiazin-3-ylidene]dipropylamine comprising the step of reacting (4-aminophenyl)dipropylamine with [2-amino-5-(dipropylamino)phenyl]-thiosulfonic acid.

6. A method for preparing 7-(dipropylamino)pheno-thiazin-3-ylidene]dipropylamine comprising the step of reacting reacting (4-{[4-(dipropylamino)phenyl]amino}phenyl)-dipropylamine with S, I₂, DCB.

7. A method of the synthesis of [7-(dipropylamino)pheno-thiazin-3-ylidene]dipropylamine comprising the step of reacting phenothiazine or any salt thereof with dipropyl amine optionally in the presence of Copper.