| 摘要 |
PURPOSE:To obtain a compound useful as an intermediate raw material for sulfonylurea based herbicides in high quality and yield by simple operation, by reacting saccharin with methanol in the presence of an acid catalyst and treating the resultant product with a weak basic aqueous solution. CONSTITUTION:100pts.wt. saccharin is reacted with 100-500pts.wt. methanol in the presence of an acid catalyst, e.g. hydrochloric acid or sulfuric acid, at 40-120 deg.C, preferably 50-100 deg.C. The resultant reaction product is then mixed and stirred with a weak basic aqueous solution, e.g. aqueous solution of sodium hydrogencarbonate, to afford the aimed substance. The amounts of the acid catalyst is 0.5-20pts.wt. based on 100pts.wt. saccharin and the amount of the weak basic substance to be added is 0.05-0.5 equivalent based on 1 equivalent saccharin. The reaction is carried out by using the weak basic aqueous solution in 1-30wt% concentration.
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