Novel method for synthesizing 2-amino-3, 5-dibromopyrazine, product and application

A technology of dibromopyrazine and aminopyrazine, applied in the direction of organic chemistry, can solve the problems of large environmental pollution, unsuitable for industrial production, and low product purity

Inactive Publication Date: 2020-03-13
上海鑫响实业有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In order to solve the problems existing in the prior art, the present invention provides a new method, product and application for synthesizing 2-amino-3,5-dibromopyrazine to solve the problem of 2-amino-3 , 5-Dibromopyrazine is difficult to synthesize, low in product purity, low in yield, high in cost, difficult to treat waste water, heavy in environmental pollution, unsuitable for industrialized production, and other technical issues

Method used

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  • Novel method for synthesizing 2-amino-3, 5-dibromopyrazine, product and application
  • Novel method for synthesizing 2-amino-3, 5-dibromopyrazine, product and application
  • Novel method for synthesizing 2-amino-3, 5-dibromopyrazine, product and application

Examples

Experimental program
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preparation example Construction

[0052] Step 1. Preparation of 2-aminopyrazine: Add 10% sodium hypochlorite aqueous solution to the three-necked flask, cool down to below 0°C, add sodium hydroxide in batches, stir and dissolve until clear; -5°C~0°C Slowly add 2- Cyanopyrazine liquid, react for 5.8-6.2 hours after the dropwise addition; slowly drop the reaction solution into water (above 85°C), and react at 90~100°C until the end of the addition; evaporate the reaction solution under reduced pressure for 60 %~90% moisture, 15~20°C, stir for 0.8~1.5 hours, filter, and dry the filtered filter cake at 55~65°C; the dried filter cake is recrystallized with toluene, and dried to light yellow Crystalline 2-aminopyrazine, the reaction path is as follows:

[0053]

[0054] (I) (II)

[0055] Among them, the chemical formula of (I) is C 5 h 3 N 3 , molecular weight (Exact Mass): 105.03; (II) chemical formula is C 4 h 5 N 3 , molecular weight (Exact Mass): 95.05.

[0056] Step 2, mid-term reaction: Add N,N-dime...

Embodiment 1

[0077] Embodiment 1. A kind of new method of synthesizing 2-amino-3,5-dibromopyrazine

[0078] This example mainly describes the new method of synthesizing 2-amino-3,5-dibromopyrazine, specifically:

[0079] The preparation of step 1, 2-aminopyrazine

[0080] The operation process of the first step reaction is: add 105g of 10% sodium hypochlorite aqueous solution to a 3000ml three-necked bottle, cool down to below 0°C, add 125g of sodium hydroxide in batches, stir and dissolve until clear; -5°C~0°C slowly drop 2-cyanopyrazine liquid (the molar ratio of 2-cyanopyrazine and sodium hypochlorite is 1:1), react for 5.8~6.2 hours after the dropwise addition. Slowly add the reaction liquid dropwise into 105g (above 85°C) water, and react at 90~100°C until the end of the addition.

[0081] Distill 90% of the water in the reaction solution under reduced pressure, stir at 15-20°C for 1 hour, filter, and dry the filtered cake at 55-65°C; recrystallize the dried filter cake with 1.05kg ...

Embodiment 2

[0088] Embodiment 2. A kind of new method of synthesizing 2-amino-3,5-dibromopyrazine

[0089] This example mainly describes the new method of synthesizing 2-amino-3,5-dibromopyrazine, specifically:

[0090] The preparation of step 1, 2-aminopyrazine

[0091] The first step reaction operation process: Add 120g of 10% sodium hypochlorite aqueous solution to a 3000ml three-necked bottle, cool down to below 0°C, add 140g of sodium hydroxide in batches, stir and dissolve until clear; -5°C~0°C Slowly add 2- Cyanopyrazine liquid (the molar ratio of 2-cyanopyrazine and sodium hypochlorite is 1:1.2), react for 5.8~6.2 hours after the dropwise addition. Slowly add the reaction liquid dropwise into 105g (above 85°C) water, and react at 90~100°C until the end of the addition. Distill most of the water (60% of the water in the reaction solution) under reduced pressure, stir at 15~20°C for 1.5 hours, filter, and dry the filter cake at 55~65°C; recrystallize the solid with 1.05kg of tolue...

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Abstract

The invention discloses a new method for synthesizing 2-amino-3, 5-dibromopyrazine, a product and an application. The method comprises the following steps: step 1, taking 2-cyanopyrazine and sodium hypochlorite as raw materials, carrying out reaction under inorganic alkali aqueous solution conditions, and then carrying out reduced pressure distillation to obtain 2-aminopyrazine; step 2, taking N,N-dimethylacetamide as a solvent, adding 1, 3-dibromo-5, 5-dimethylhydantoin, dropwise adding an N, N-dimethylacetamide solution of 2-aminopyrazine, and carrying out reaction for 15 to 20 h so as to obtain a 2-amino-3, 5-dibromopyrazine crude product; carrying out subsequent treatment on the 2-amino-3, 5-dibromopyrazine crude product with heptane and ethanol to obtain the 2-amino-3, 5-dibromopyrazine disclosed by the invention. The invention provides the new method for synthesizing 2-amino-3, 5-dibromopyrazine, the yield of the product is improved, the purification problem of the product is solved, and meanwhile, the synthesis cost of the product is reduced.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and specifically relates to a new method, product and application for synthesizing 2-amino-3,5-dibromopyrazine. Background technique [0002] At present, the synthetic report of 2-amino-3,5-dibromopyrazine is less, and there are some shortcomings, disclose a kind of preparation method of 2-aminopyrazine derivative as patent CN108570011A, comprise the following steps: C1: to Add sodium hypochlorite solution and alkali in sequence to 2-cyanopyrazine, and then stir to obtain 2-aminopyrazine; C2: add the 2-aminopyrazine obtained in step C1 to a brominating agent for bromination reaction to obtain 2-aminopyrazine -3,5-Dibromopyrazine. The disadvantages of this patent are: the prepared product has low purity, low yield, high cost, difficult treatment of waste water, and great environmental pollution. [0003] Therefore, it is necessary to provide an improved technical solution to overcome t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D241/20
CPCC07D241/20
Inventor 陈建平
Owner 上海鑫响实业有限公司
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