Synthetic method for diethyl acetamidomalonate

Abstract

The invention discloses a synthetic method for diethyl acetamidomalonate. The method comprises the following steps: firstly, performing a reaction in the presence of a metal salt and a ligand to prepare a mixed liquid containing the diethyl acetamidomalonate by taking diethyl malonate and acetamide as raw materials, air as an oxidant, and acetic acid as a solvent, performing distilling, and performing repeated extraction and recrystallization to obtain the diethyl acetamidomalonate in a white crystalline powder state. The method has the advantages that the metal salt and the ligand are cheap and easy to obtain, after the reaction is finished, the metal salt and the ligand can be further recycled through treatment, the air is taken as the oxidant, and therefore the production costs are greatly reduced; the yield of the product is more than 90%, the purity of the product is more than 99%, the conversion rates of the raw materials are high, and the reaction is complete; and the by-productis only water, no ''three waste'' (waste gas, waste water and solid waste) pollution problems exist, and the method meets environmental protection requirements.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a method for synthesizing diethyl acetamidomalonate. Background technique [0002] Diethyl acetamidomalonate, also known as diethyl α-acetamidomalonate, is a kind of molecular formula C 9 h 15 NO 5 chemicals. It is mostly used in the pharmaceutical industry and downstream chemical synthesis. [0003] At present, most of the synthesis methods of diethyl acetamidomalonate use diethyl malonate and sodium nitrite as raw materials, but this synthesis method has problems such as large amount of "three wastes" and difficult treatment, high production cost and product The disadvantages such as low yield, such as a new process for preparing acetamidodiethyl malonate disclosed in Chinese invention patent specification CN200610082017.1, that is, using diethyl malonate and sodium nitrite as starting materials, Diethyl nitrosomalonate, acylating agent, and solvent are mixed in a molar r...

AI Technical Summary

Problems solved by technology

[0003] At present, most of the synthesis methods of diethyl acetamidomalonate use diethyl malonate and sodium nitrite as raw materials, but this synthesis method has problems such as large amount of "three wastes" and difficult treatment, high production cost and product The disadvantages such as low yield, such as a new process for preparing acetamidodiethyl malonate disclosed in Chinese invention patent specification CN200610082017.1, that is, using diethyl malonate and sodium nitrite as starting materials, Diethyl nitrosomalonate, acylating agent, and solvent are mixed in a molar ratio of 1:1-2:1-2, and the reducing agent is added under temperature control. After the acylation reaction is complete, the catalyst is removed by filtration, and the filtrate is passed through Recover acetic acid by distillation under reduced pressure, and obtain the finished product after washing and drying the filter cake

Although this method saves raw materials, it is difficult to regenerate the catalytic reducing agent and the utilization rate is low

Another example is a new process for the preparation of pharmaceutical intermediate AMD disclosed in China's invention patent specification CN200710109988.5, which has invented a method for preparing acetamidodiethyl malonate by electroreduction. and sodium nitrite as raw material to prepare diethyl nitrosomalonate, then diethyl nitrosomalonate as raw material, sodium acetate, acetic acid, sodium sulfate solution as electrolyte, on the plate with a diaphragm In the frame-type electrolyzer, direct current is used to electroreduce the raw materials to produce the intermediate diethyl aminomalonate, and the reduced product is further acylated to prepare diethyl acetamidomalonate. However, this method requires relatively high electrode materials. And expensive, which limits its mass production