Patent GB-414453-A (GB)
Title: Process for the manufacture of aminonaphthol sulphonic acids containing residues of bile acids and for the manufacture of dyestuffs therefrom
IPC: C07C309/50
Filed: 1933-03-15
Abstract: Aminonaphtholsulphonic acids; azo dyes.--Compounds containing bile acid residues are obtained by treating 1 : 8-aminonaphtholsulphonic acids with chlorides or azides of bile acids such as cholic, desoxycholic, glycocholic and taurocholic acids.  The products yield azo dyes by coupling preferably in an alkaline medium with diazotized monamines or aminoazo compounds or tetrazotized diamines.  The aminonaphtholsulphonic acid compounds and the azo dyestuffs therefrom have strong bactericidal action and are of therapeutic value.  The following examples are specified.  (1) A suspension of cholic acid azide in ice-water is slowly added to a solution of the acid sodium salt of 1 : 8-aminonaphthol-3 : 6-disulphonic acid in dilute sodium hydroxide and the mixture, after standing for some time, is warmed to 60 DEG  C. to complete the reaction; on cooling the solution is acidified with acetic acid, allowed to stand overnight and filtered, and the acid sodium salt of 1 : 8-cholalylaminonaphthol-3 : 6-disulphonic acid is salted out from the filtrate and purified by recrystallization from alcohol.  (2) The acid sodium salt of 1 : 8 - cholalylaminonaphthol - 2 - 4 - disulphonic acid is similarly obtained.  (3) Desoxycholic acid azide is added to a solution of 1 : 8-aminonaphthol-3 : 6-disulphonic acid in dilute sodium hydroxide and the mixture is heated for 30 minutes to 55 DEG  C. acidified with acetic acid and filtered; the filtrate is concentrated in vacuo at 50 DEG  C. and treated with absolute alcohol to precipitate the acid sodium salt of 1 : 8-desoxycholalylaminonaphthol - 3 : 6 - disulphonic acid which is washed with alcohol and recrystallized from hot aqueous alcohol. (4) The product of example 1 or 2 is coupled in sodium bicarbonate solution with diazotized 1 : 8-aminonaphthol-3 : 6-disulphonic acid; the azo dyestuff is precipitated by adding methanol and ether and dissolved in water and the solution is then dialysed to separate mineral salts and the product is precipitated by adding alcohol and ether.  (5) 1 : 8-Cholalylaminonaphthol-3 : 6-disulphonic acid is coupled in sodium carbonate solution with tetrazotized o-tolidine and the dyestuff is extracted as in (4). The sample furnished is of the dyestuff o-toluidine --> o - toluidine --> 1 : 8 - cholalylaminonaphthol - 3 : 6-disulphonic acid.  Cholic and desoxycholic acid azides are obtained by the action of hydrochloric acid and sodium nitrite on cholic and desoxycholic acid hydrazides respectively.  The Specification as open to inspection under Sect. 91 comprises also the use as starting materials of chlorides and azides of acetylcholic, acetylglycocholic and diformyldesoxycholic acids and includes an example of the preparation of 1 : 8-diformyldesoxycholalylaminonaphthol-4-sulphonic acid from diformyldesoxycholic acid chloride (obtained by treating the acid with thionyl chloride or a phosphorus chloride at 60--70 DEG  C.) and 1 : 8-aminonaphthol-4-sulphonic acid.  This subject-matter does not appear in the Specification as accepted.