Patent GB-461430-A (GB)
Title: Improvements in the manufacture and production of water-soluble leuco compounds
IPC: C09B9/02
Filed: 1935-07-10
Abstract: Water-soluble leuco compounds are prepared by acting on anthraquinone derivatives containing a nitrogenous ring in the 1.9-position, one ring-nitrogen atom being attached to the 9-position and having from 4 to 5 rings condensed together, with sulphur trioxide in the presence of an organic basic diluent and a metal.  As basic diluents dimethylaniline, pyridine or quinoline bases are preferred; suitable metals are copper, iron, zinc and aluminium; sulphur trioxide may be used in admixture with sulphuric or chlorsulphonic acid.  It is preferable to keep temperature as low as possible and in many cases to salt out the compound first formed by means of common salt, potassium chloride or calcium chloride.  In examples: (1) 5 - (2<1> . 5<1> - dichlorbenzoylamino) - 1 . 9 - anthrapyrimidine, pyridine, sulphur trioxide and copper powder are warmed together at 50 DEG  C., cooled, ammonia added and the ester salted out with potassium chloride; there may be converted in similar manner the acylamino compounds of 2-, 3-, 4-, 5-, 6-, 7-, 8- or PyC-aminoanthrapyrimidines, the acyl radicle being derived from fluoro-, alkyl-, aryl-, nitro-, amino-, acylamino-, chlorbromo-, chlormethyl-, or chlorphenyl-benzoic acids, or from anthraquinone carboxylic acids (derived by acting on methylanthraquinones with oxidizing agents), nitroanthraquinone carboxylic acids (prepared by nitrating the carboxylic acids or by oxidizing 1 - nitro - 2 - methylanthraquinone), benzanthraquinone carboxylic acids (prepared by bromination of the benzanthraquinone, heating the bromo derivative with cuprous cyanide and saponifying), carboxylic acids of quinolines, naphthalenes, pyridinoanthraquinones (prepared by a Skraup synthesis from aminoanthraquinone carboxylic acids) anthraquinone acridones, anthraquinonethioxanthones (prepared by reacting 1-mercaptoanthraquinone-2-carboxylic acid with p-chlorbenzoic acid and ring-closing), diphenyleneoxides, diphenylenesulphides, pyrenes, chrysenes, benzperylenes, perylenes (prepared by nitration of these hydrocarbons, reduction, diazotisation and a Sandmeyer replacement to a cyano group followed by saponification), anthanthrones, carbazoles, alloms-naphthodianthrones (prepared by a Sandmeyer replacement of an amino group in an amino derivative to a cyano group and saponifying), and anthraquinonecarbazoles (similarly prepared from amino derivatives of anthraquinonecarbazoles); a mixture of sulphur trioxide and chlorsulphonic acid may be used and iron may replace copper, while quinoline, quinaldine, methyl- or ethyl-pyridine may be used instead of pyridine: (2) 4-(2<1>.5<1>-dichlorbenzoylamino) - 1 . 9 - anthrapyrimidine, pyridine, sulphur trioxide, chlorsulphonic acid and copper powder are warmed together to 50--55 DEG  C. and the ester isolated as in (1); 4-amino-1.9-anthrapyrimidine, PyC-methyl-4-acylamino-1 . 9 - anthrapyrimidines and 2-bromo-4-acylamino-1.9-anthrapyrimidines may similarly be converted: (3) 4-(2<1>.5<1>-dichlorbenzoylamino)-anthrapyrimidine, pyridine, fuming sulphuric acid and copper powder are warmed together to 60 DEG C. and the ester isolated as in (1); there may be prepared similarly the leuco ester of the acylamine from 4-amino-N-methyl-1.9-anthrapyrimidone and 1-nitroanthraquinone-2-carboxylic acid chloride: (4) N.N<1>-diethyl-2.2<1>-dipyrazolanthronyl (prepared by treating pyrazolanthrone with alcoholic potassium hydroxide at 140--150 DEG C. and the product with diethylsulphate), pyridine, sulphur trioxide, chlorsulphonic acid and copper powder are warmed together at 45 DEG C. and the ester salted out; in a similar manner may be made the esters of 2.2<1>-dipyrazolanthronyl and N.N<1>-dimethyl - 2 . 2<1> - dipyrazolanthronyl (prepared by acting on 2.2<1>-dipyrazolanthronyl) : (5) 4 - b  - anthraquinonoylamino - 1 . 9 - anthrapyrimidine, pyridine, copper and sulphur trioxide are warmed together to 60 DEG C. and the ester salted out: (6) the condensation product from 1 - aminoanthraquinone and thiazolanthrone-2-carboxylic acid chloride, pyridine, fuming sulphuric acid, and copper powder are warmed together to 40 DEG  C. and the ester salted out; acylamines of thiazolanthrone carboxylic acids, selenazolanthrone or pyrazolanthrone carboxylic acids may similarly be converted into stable water-soluble leuco compounds.  Bz3-azobenzanthrones are also specified as starting-materials.  The products are considered to be sulphaminic acid-sulphuric acid esters of the quinone-imino compounds.  Specification 385,295 is referred to.  Reference has been directed by the Comptroller to Specifications 251,491 and 261,139, [both in Class 2 (iii)].