Crystalline p-amino:phenyl:sulphonyl:urea prodn. in high purity - comprises saponification of p-acetyl:aminophenyl:sulphonyl:urea under controlled temp. pH and time conditions

摘要

Prodn. of crystalline p-aminophenylsulphonylurea (I) comprises saponifying p-acetylaminophenylsulphonyl urea (II) at 5-65 deg. C in water and sodium hydroxide soln. for 0.5 hr., neutralising to pH 7, stirring for 0.5 hr., acidifying to pH 2-3 and stirring at room temp. for 1 hr.. The deacetylation, neutralisation and acidification are carried out at 60-65 deg. C. The wt. ratio water:NaOH:(II) is 3-10:0.5-1:1 and an inorganic acid, esp. HCl or H2SO4, is used for the neutralisation and acidification. USE/ADVANTAGE - The method provides an industrially applicable, simple and practical route to the pharmaceutically useful (I). The method gives (I) in higher yields and purity (above 99.5%) than the prod. obtd. by the process of US 2411661 which contains 2-5% byprods.. Further, (I) is easier to purify than the known