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Synthesis method of tert-butyl 2-(methylamino)ethylcarbamate

A technology of ethyl carbamate and methylamino, which is applied in the field of synthesis of tert-butyl 2-(methylamino)ethyl carbamate, can solve the problems of high cost of precious metal catalysts, unfavorable industrial production, low overall yield and the like , to achieve the effect of facilitating industrial production, reducing the amount of wastewater treatment, and high reaction yield

Active Publication Date: 2015-06-03
SUZHOU HIGHFINE BIOTECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

2-( tert-butyl methylamino)ethylcarbamate (Federico Corellia, Maurizio Bottaa, Andrea Lossanib, Serena Pasquinia, Silvio Spadarib, Federico Focherb, F. Corelli et al. / IL FARMACO 59 (2004) 987–992), the method The prices of the two raw materials are relatively high, especially the price of N-methylethylenediamine is higher, the economic cost is higher, and it is not suitable for enlarged production. The specific route is as follows:
The disadvantage of this method is similar to that of method (1). The selectivity of the second step reaction is poor, and a large amount of dialkylated by-products are produced at the same time. It is difficult to purify the pure product through recrystallization. The specific route is as follows:

Method used

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  • Synthesis method of tert-butyl 2-(methylamino)ethylcarbamate
  • Synthesis method of tert-butyl 2-(methylamino)ethylcarbamate
  • Synthesis method of tert-butyl 2-(methylamino)ethylcarbamate

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Preparation of 2-(N-isobutoxycarboxamido) ethyl isocyanate, the specific steps are as follows:

[0027] In a 1000ml three-neck flask (with water separator), N-Boc-ethylenediamine (160g, 1mol) and paraformaldehyde (31.5g, 0.35mol) were dissolved in toluene (500ml), and acetic acid (0.3g ), heated to reflux for 5 hours until no more water was separated from the water separator. Then, the reaction solution was concentrated to remove the solvent, the residue was dissolved in ethyl acetate (500ml), washed with water (300ml), saturated aqueous sodium carbonate solution (300ml) and saturated brine (300ml) successively, and the organic phase was dried, Concentrate to obtain product 108 g oily liquid, yield 62%.

Embodiment 2

[0029] Preparation of 2-(N-isobutoxycarboxamido) ethyl isocyanate, the specific steps are as follows:

[0030] In a 1000ml three-necked flask (with water separator), N-Boc-ethylenediamine (160g, 1mol) and paraformaldehyde (31.5g, 0.35mol) were dissolved in benzene (500ml), and p-toluenesulfonic acid was added dropwise (0.45g), heated to reflux for 5.5 hours until no more water was separated in the water separator. Then, the reaction solution was concentrated to remove the solvent, the residue was dissolved in ethyl acetate (500ml), washed with water (300ml), saturated aqueous sodium carbonate solution (300ml) and saturated brine (300ml) successively, and the organic phase was dried, Concentrate to obtain product 113 g oily liquid, yield 65%.

[0031] Examples 1 and 2 can be repeated according to actual needs to obtain more 2-(N-isobutoxycarboxamido)ethyl isocyanide for subsequent examples.

Embodiment 3

[0033] Prepare tert-butyl 2-(methylamino)ethyl carbamate, the specific steps are as follows:

[0034] In a 1000ml three-necked flask, 2-(N-isobutoxycarboxamido) ethyl isocyanate (172 g, 1mol) was dissolved in tetrahydrofuran (600ml), at room temperature (about 20°C~30°C) Add sodium borohydride (74 g, 2mol) in batches, after the addition is complete, stir at room temperature for 4 hours, add acetic acid to quench unreacted sodium borohydride, concentrate to remove tetrahydrofuran, add water (500ml), ethyl acetate (500ml×2 ) extraction, the organic phases were combined and washed with saturated brine (500ml), the organic phase was dried and concentrated to obtain an oily crude product, which was distilled under reduced pressure by an oil pump to obtain 148 g of a colorless oily product with a yield of 85%.

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Abstract

The invention provides a synthesis method of tert-butyl 2-(methylamino)ethylcarbamate, which is characterized by comprising the following steps: (a) carrying out reduction reaction on N-tert-butyloxycarbonyl-1,2-ethylenediamine and polyformaldehyde in an organic solvent in the presence of acid at reflux temperature to obtain 2-(N-isobutoxyformamido)ethylisocyanide; and (b) carrying out reduction reaction on the 2-(N-isobutoxyformamido)ethylisocyanide and sodium borohydride in an aprotic solvent at 20-30 DEG C to obtain the tert-butyl 2-(methylamino)ethylcarbamate. The method has the advantages of higher two-step reaction yield, lower cost and less generated waste liquor, and is convenient for industrial production. The structural formula is disclosed in the specification.

Description

technical field [0001] The invention relates to a pharmaceutical intermediate, more particularly to a method for synthesizing tert-butyl 2-(methylamino)ethyl carbamate. Background technique [0002] Methylethylenediamine is an important fine chemical and pharmaceutical intermediate, which can be used to prepare antibiotics rifampicin, anti-homogeneous drugs pefloxacin, difloxacin, etc. Oxidation and substitution reactions are prone to generate a mixture of primary and secondary amino groups. In order to enable the molecule to undergo a monoamination reaction, it is necessary to selectively protect the amino group. 2-(Methylamino)ethylcarbamate tert-butyl ester is Boc The protective group selectively protects the product of the primary amino group, and reacts with tert-butyl 2-(methylamino)ethylcarbamate instead of N-methylethylenediamine, which can effectively improve the efficiency of trans-methyl N-alkyl alkylation Directivity, avoiding the exposure of N-methylethylenedia...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C271/20C07C269/06
Inventor 吕敏杰张海燕王桂春孙方超
Owner SUZHOU HIGHFINE BIOTECH
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