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Method for preparing N-substituted ethyl carbamate

A technology of ethyl carbamate and ethyl acetate, which is applied in the preparation of N-substituted ethyl carbamate and the field of preparation of N-substituted ethyl carbamate, which can solve the lack of structure of dimethyl carbonate and urea compounds Diversity, not suitable for large-scale production, low yield of target products, etc., to achieve the effect of cheap raw materials, low cost, and high yield

Inactive Publication Date: 2012-03-14
NORTHWEST NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0015]The disadvantage of this method is that the structure of the raw material dimethyl carbonate and urea compounds lacks diversity and the price is relatively high
[0027] This method catalyzer is often the complex compound of Pd or the compound of Pb, selectivity is poor, and target product yield is not high
[0028]7. Hoffman rearrangement method: P. Gogoi reported in "Tetrahed. Lett." in 2007, using amide as the starting material and NaOCl as the oxidizing agent , under the action of catalyst KF / Al2O3, the corresponding N-substituted carbamate compounds are obtained by Hoffman rearrangement reaction with alcohols, the method Only suitable for a small amount of synthesis in the laboratory, not suitable for large-scale production

Method used

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  • Method for preparing N-substituted ethyl carbamate
  • Method for preparing N-substituted ethyl carbamate
  • Method for preparing N-substituted ethyl carbamate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Embodiment one, the preparation of ethyl phenylcarbamate

[0042] (1) Preparation of Reformatsky reagent (ethyl zinc bromide acetate): Add zinc powder (0.50 g, 7.69 mmol) and tetrahydrofuran (5 mL) into a 50 mL two-neck flask, add 1, 2-Dibromoethane (0.01 mL), heated until the solution boiled slightly, cooled naturally to room temperature, added trimethylchlorosilane (0.01 mL), stirred for 15 minutes, added ethyl bromoacetate (1.26 g, 7.57 mmol) , reacted at 45°C for 10 hours under the protection of nitrogen, the zinc powder reacted completely, and the Reformazky reagent was obtained with a yield of more than 95%.

[0043] (2) Preparation of ethyl phenylcarbamate: Add phenylisocyanate (0.30 g, 2.48 mmol) and tetrahydrofuran (5 mL) into a 50 mL two-neck flask, then slowly add ethyl zinc bromide acetate (2.48 mmol), reacted at 40°C for 8 hours under the protection of nitrogen, TLC detected the disappearance of the raw materials, quenched the reaction with saturated ammo...

Embodiment 2

[0046] Embodiment two, the preparation of ethyl 3-nitrophenylcarbamate

[0047] (1) Preparation of Reformatzky reagent (ethyl zinc bromide acetate): same as Example 1.

[0048] (2) Preparation of ethyl 3-nitrophenylcarbamate: Add 3-nitrophenylisocyanate (0.41 g, 2.48 mmol) and tetrahydrofuran (5 mL) into a 50 mL two-necked flask, then slowly add bromine dropwise Zinc ethyl acetate (4.96 mmol) was reacted at 40°C for 8 hours under the protection of nitrogen. TLC detected that the starting material disappeared, and the reaction was quenched with saturated ammonium chloride solution (5 mL), and the organic phase was extracted with diethyl ether (3×40 mL). Dry the organic solvent with anhydrous magnesium sulfate, filter, evaporate the solvent to dryness, and perform column chromatography (ethyl acetate:petroleum ether=1:5) to obtain a light yellow solid (0.40 g, 1.91 mmol) which is the target product with a yield of 77 %. Melting point: 68-70°C.

[0049] Its various performan...

Embodiment 3

[0051] Embodiment three, the preparation of ethyl 4-chlorophenylcarbamate

[0052] (1) Preparation of Reformatzky reagent (ethyl zinc bromide acetate): same as Example 1.

[0053] (2) Preparation of ethyl 4-chlorophenylcarbamate: Add 4-chlorophenylisocyanate (0.38 g, 2.48 mmol) and tetrahydrofuran (5 mL) into a 50 mL two-necked flask, then slowly add zinc bromide dropwise Ethyl acetate (7.20 mmol), reacted at 45°C for 10 hours under nitrogen protection, TLC detected the disappearance of the starting material, quenched the reaction with saturated ammonium chloride solution (5 mL), extracted the organic phase with diethyl ether (3×40 mL), and used The organic solvent was dried with anhydrous magnesium sulfate, filtered, and evaporated to dryness. After column chromatography (ethyl acetate: petroleum ether = 1:5), the target product was obtained as a white solid (0.35 g, 1.74 mmol), with a yield of 70%. Melting point: 71-73°C.

[0054] Its various performance indicators or ch...

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Abstract

The invention discloses a method for preparing N-substituted ethyl carbamate, which belongs to the technical field of chemical synthesis. According to the invention, the method comprises the following steps of: by using tetrahydrofuran as solvent and isocyanate as raw material, reacting tetrahydrofuran and isocyanate for 8-12 hours at 40-45 DEG C under the effect of a Reformatsky reagent (zinc bromide based ethyl acetate); and extracting and purifying a reaction product so as to obtain the N-substituted ethyl carbamate. The method for preparing the N-substituted ethyl carbamate, disclosed by the invention, has the advantages of single synthesis product, high total yield (more than 70%), high purity (more than 99%), simple synthesis process, higher efficiency, mild reaction condition and friendliness to environment.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and relates to a preparation method of N-substituted ethyl carbamate, in particular to a method for preparing N-substituted ethyl carbamate by using isocyanate as a raw material under the action of Reformatzky reagent Preparation. Background technique [0002] Carbamate compounds have a wide range of uses and can be used as intermediates in pesticides, medicines, synthetic resin modification, and organic synthesis. N-substituted urethane is an important carbamate compound, its structure is as follows: [0003] [0004] Wherein R represents an alkyl group, a cycloalkyl group, an unsaturated hydrocarbon group or an aryl group. [0005] N-substituted carbamates have a wide range of characteristics of carbamate compounds. In the pesticide industry, N-substituted carbamates are widely used in herbicides, insecticides and acaricides due to their variety, good efficacy and low toxicity. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C269/02C07C271/28
Inventor 胡雨来杨皓然黄丹凤
Owner NORTHWEST NORMAL UNIVERSITY
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