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1. 发明专利

GB636347A Improvements in and relating to the manufacture of aromatic amino carboxylic acids 未知
公开(公告)号：GB636347A
公开(公告)日：1950-04-26
申请号：GB1520547
申请日：1947-06-10
申请人： HERTS PHARMACEUTICALS LTD , DAVID DUNCANSON MARTIN , DONALD EDWIN SEYMOUR , FRANK STUART SPRING
摘要： Alkali metal salts of 2-hydroxy-4-amino-benzoic acid are prepared by heating m-aminophenol with carbon dioxide and alkali metal hydroxide, carbonate or bicarbonate at 105-135 DEG C. in a polyhydric alcohol. The free acid may be isolated by adding hydrochloric acid to the reaction product until just acid to litmus or by adding the reaction product to an excess of hydrochloric acid to precipitate the hydrochloride of the amino acid which is separated, dried and decomposed by the addition of an alkali metal bicarbonate and just sufficient water to dissolve the alkali metal chloride formed. In an example, m-amino-phenol is heated with potassium bicarbonate in glycerol at 130 DEG C. while a stream of carbon dioxide is passed in, the product is converted to the hydrochloride from which the free acid is liberated by the addition of the equivalent quantity of sodium bicarbonate.

2. 发明专利

GB636333A Improvements in and relating to the manufacture of aromatic amino carboxylic acids 未知
公开(公告)号：GB636333A
公开(公告)日：1950-04-26
申请号：GB523247
申请日：1947-02-22
申请人： HERTS PHARMACEUTICALS LTD , DAVID DUNCANSON MARTIN , DONALD EDWIN SEYMOUR , FRANK STUART SPRING
摘要： Alkali metal salts of 4-amino-2-hydroxy benzoic acid are prepared by the reaction of carbon dioxide with m-aminophenol in the presence of an alkali metal hydroxide, carbonate or p bicarbonate and water, preferably at a temperature of over 100 DEG C. Conveniently, the reaction may be carried out by heating m-amino phenol with the alkali-metal compound and solid carbon dioxide in an autoclave at about 130 DEG C. The free acid may be liberated from the reaction product by adding dilute hydrochloric acid until just acid to litmus, or by dissolving in an excess of hydrochloric acid to form the aminoacid hydrochloride which is separated and dried and treated with an equivalent quantity of an alkali metal bicarbonate and just sufficient water to dissolve the alkali metal chloride formed. In examples: (1) m-aminophenol, potassium bicarbonate, solid carbon dioxide and water are heated in an autoclave and the reaction product is neutralized with hydrochloric acid to give 4-amino-2-hydroxy benzoic acid; (2) sodium bicarbonate is used in place of potassium bicarbonate in (1) and (3), the process (1) is repeated using gaseous carbon dioxide in place of solid carbon dioxide and the product is separated by means of the aminoacid hydrochloride. Reference has been directed by the Comptroller to Berichte der Deutschen Chemischen Gesellschaft (Referat), Volume 23 (1890), page 313.

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