摘要 |
<p>The anhydrides of isatoic acid and 3-aza isatoic acid, for use in making pharmaceutical and agricultural prods., and perfumery essences, are made by (a) reacting an imide of formula (I) in which X is Br or Cl and Z is N or CH, in aq. medium contg. 1.5-3 equivs. alkali or alkaline earth hydroxide per equiv. imide at around 0 deg.C with slow stirring; (b) cooling for sufficient time to achieve pH 5.5-7; (c) heating to 30-45 deg.C with an exothermic reaction, keeping at pH 5.5 min. until complete, and (d) filtering off, washing and drying the anhydride crystals.</p> |