Method for synthesizing 2-ethoxycarbonylaminosulfonyl-N,N-dimethyl nicotinamide

Abstract

The invention relates to a novel method for synthesizing 2-ethoxycarbonylaminosulfonyl-N, N-dimethyl nicotinamide. 2-ethoxycarbonylaminosulfonyl-N,N-dimethyl nicotinamide is prepared by the following steps of taking liquid alkali as an acid binding agent; performing reaction of 2-aminosulfamide-N,N-dimethyl nicotinamide and ethyl chloroformate; adding 2-aminosulfamide-N,N-dimethyl nicotinamide into an acetone aqueous solution, adding ethyl chloroformate and liquid alkali into acetone aqueous solution while stirring; preserving heat till the completion of the reaction, distilling and recyclingacetone; filtering; separating; and drying to obtain the finished product. The product prepared by the method saves energy and reduces consumption and achieves the environmental safety; no pollutantssuch as carbon dioxide and salt-containing waste water are generated; and the yield and the content of the 2-ethoxycarbonylaminosulfonyl-N,N-dimethyl nicotinamide is high.

Description

technical field [0001] The invention belongs to the field of pesticides, and in particular relates to a synthesis method of an intermediate 2-ethoxycarbonylaminosulfonyl-N,N-dimethylnicotinamide for preparing nicosulfuron. Background technique [0002] Nicosulfuron is a sulfonylurea herbicide for cornfields. Due to its high selectivity, unique mechanism of action, and high safety, it has been widely used as a herbicide in cornfields. Its cost price sells well in the market. Many domestic pesticide manufacturers are producing this product. The synthetic route of nicosulfuron generally uses 2-chloronicotinic acid as the starting material, and the final product is synthesized through steps such as acyl chloride, amination, esterification, and condensation. The steps are many , The process is complex. [0003] Therefore, most manufacturers directly purchase intermediates to synthesize nicosulfuron, among which 2-ethoxycarbonylaminosulfonyl-N, N-dimethylnicotinamide is an impor...

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Problems solved by technology

Because this reaction needs to be carried out at freezing low temperature, so energy will be wasted; and the tail gas produced in the reaction process is carbon dioxide gas, and produces a large amount of saline wastewater, which pollutes the environment greatly, and the subsequent treatment is more troublesome, but according to the prior art It is impossible to completely treat the waste water up to the standard

In addition, because acetonitrile is a polar solvent, it is difficult to separate from water, so it is difficult to recycle and use the solvent, so the production scale is limited to a large extent.

[0004] Another synthetic method is to use acetone as a solvent, potassium carbonate as an acid-binding agent, and react 2-aminosulfonamide-N, N-dimethylnicotinamide with ethyl chloroformate to prepare 2-ethoxycarbonylsulfamate Acyl-N, N-dimethylnicotinamide, although the solvents are different, but the use of potassium carbonate has caused a certain degree of pollution to the environment and has not yet been resolved

[0005] It is also reported that toluene is used as a solvent, and the content and yield of 2-ethoxycarbonylaminosulfonyl-N, N-dimethylnicotinamide are low, and toluene is serious to environmental pollution

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