A kind of method of catalytic oxidative carbonylation synthesis unsymmetrical disubstituted urea

Abstract

The invention discloses a novel method for directly synthesizing asymmetric disubstituted urea compounds. The method comprises the step of adding a palladium catalyst into a solvent polyethylene glycol or a polyethylene glycol water solution under the action of alkali, an iodine compound and an oxidant so as to catalyze direct cross coupling reaction of primary amine and carbon monoxide, so as to prepare the asymmetric disubstituted urea compounds. The method for preparing the asymmetric disubstituted urea compounds through the coupling reaction has the advantages that the catalyst is wide in source and environment-friendly; a substrate is wide in source, cheap and easy to process; a carbonyl is stable in source and cheap and does not generate waste; a ligand is not required in the reaction, and the reaction activity is good; reaction conditions are mild, and the reaction selectivity is high; the substrate has good functional group consistency and is wide in application range; and a reaction medium is environment-friendly and can be circularly recycled. The separation yield of a target product can reach up to about 97% under optimized reaction conditions.

Description

technical field [0001] The invention belongs to the field of catalytic synthesis technology and fine chemical synthesis, more specifically, relates to a synthetic method for catalytically synthesizing asymmetric disubstituted urea compounds, which is a method of directly using primary amine compounds, carbon monoxide as carbonyl source and air Or oxygen as an oxidant to cross-coupling to prepare asymmetric disubstituted urea. Background technique [0002] The skeleton structure of unsymmetrical disubstituted urea is widely found in natural products, insecticides, herbicides and medicines, and its synthetic methods have attracted extensive attention because of its wide range of pharmacological and physiological activities. The traditional method of synthesizing asymmetric disubstituted urea is the isocyanate method based on phosgene: although the yield of this reaction is high, this method is due to the high toxicity of raw materials, and a large amount of highly corrosive an...

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Problems solved by technology

[0004] The raw materials of the traditional method of synthesizing urea are highly toxic, and a large amount of highly corrosive and polluting chlorine-containing wastes are generated during the reaction, causing serious corrosion of equipment and difficulties in post-processing of products. At the same time, the activity of isocyanate is very high. The reaction is carried out under anhydrous, oxygen-free and nitrogen protective atmosphere, and the operation is relatively complicated; and the existing palladium-catalyzed method for synthesizing urea requires the use of a metal oxidant, and there is a problem of poor selectivity for the synthesis of asymmetric disubstituted urea

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