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Preparation method of 2-aminopyrazine derivatives

A technology of aminopyrazine and derivatives, which is applied in the field of preparation of 2-aminopyrazine derivatives, can solve the problems of long route, heavy pollution, high cost, etc., and achieve the effects of high yield, cheap and easy-to-obtain raw materials, and simple operation

Inactive Publication Date: 2016-06-01
HUBEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] At present, there are few reports on the synthesis of 2-aminopyrazine derivatives, and there are some shortcomings, such as long route, large pollution, high cost, etc. The present invention discloses a synthetic method with simple operation, mild conditions, little pollution and low cost , which is conducive to large-scale production

Method used

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  • Preparation method of 2-aminopyrazine derivatives
  • Preparation method of 2-aminopyrazine derivatives
  • Preparation method of 2-aminopyrazine derivatives

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The preparation of embodiment 1,2-aminopyrazine

[0021]

[0022] In a 500ml three-neck flask, add 20% sodium hydroxide (30g) solution and sodium hypochlorite solution (100ml), add 2-cyanopyrazine (21g, 0.2mol) at room temperature, and stir for 1h. Then react at 50°C-60°C for 4h, extract with dichloromethane (4×200ml), dry over anhydrous sodium sulfate, filter, and concentrate under reduced pressure to obtain 15.7g of white solid with a yield of 82.6%. Melting point 118-121°C; 1 H-NMR (CDCl 3 , 400MHz): δ7.72 (S, 1H, CH), 7.89 (S, 1H, CH), 7.91 (S, 1H, CH), 4.2 (S, 2H, NH2).

Embodiment 2

[0023] The preparation of embodiment 2,2-amino-3,5-dibromopyrazine

[0024]

[0025] In a 500ml three-necked flask, add a mixed solution of 2-aminopyrazine (19g, 0.2mol), dichloromethane (200ml) and pyridine (50ml), slowly add bromine (67.2g, 0.42mol) dichloro Methane (100ml) solution, stirred at room temperature for 4h, 100ml of water was added to the reaction system, stirred for 2h, the organic layer was washed with water (100ml×3), the organic phase was transferred to a flask equipped with silica gel and activated carbon, heated to reflux for 1h, and suction filtered , The solvent was distilled off under reduced pressure, and the resulting solid was added to n-hexane (45ml), refluxed for 2h and then filtered while hot. After drying, 39.4g of a yellow solid was obtained, with a yield of 77.8%. Melting point: 115-118°C; 1 H-NMR (CDCl 3 , 400MHz): δ7.91(S, 1H, CH), 4.2(S, 2H, NH 2 ).

Embodiment 3

[0026] The preparation of embodiment 3,2-amino-5-bromo-3-morpholinopyrazine

[0027]

[0028] In a 500ml three-necked flask, add morpholine (9.6g, 0.11mol), 2-amino-3,5-dibromopyrazine (25.3g, 0.1mol) and N-methylpyrrolidone (100ml), at 80°C The reaction was carried out for 6 hours, followed by TLC. After cooling to room temperature, 400 ml of water was added, stirred, and dried by suction filtration to obtain 22.5 g of a yellow solid with a yield of 86.7%. Melting point 134-137°C; 1 H-NMR (DMSO, 400MHz): δ7.70 (S, 1H), 6.28 (S, 2H), 3.85-3.62 (m, 4H).

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Abstract

The invention relates to a preparation method of 2-aminopyrazine derivatives, and belongs to the technical field of organic synthesis.With 2-cyanopyrazine as the raw material, by adding a sodium hypochlorite solution and alkali, 2-aminopyrazine is prepared through reaction, then 2-amino-3,5-dibromopyrazine is obtained through bromination reaction, and 2-amino-5-bromine-3-morpholinopyrazine, 2-amino-5-bromine-3-piperazinylpyrazine and 2-amino-5-bromine-3-pyrrolidylpyrazine are obtained after substitution reaction is conducted on 2-amino-3,5-dibromopyrazine as the raw material together with morpholine, piperazine and pyrrole respectively.With 2-cyanopyrazine as the raw material, different 2-aminopyrazine derivatives are prepared, the raw materials are low in price and easy to obtain, operation is easy, and target product yield is high.

Description

technical field [0001] The invention relates to a preparation method of 2-aminopyrazine derivatives, belonging to the technical field of organic synthesis. Background technique [0002] 2-aminopyrazine derivatives are the key intermediates of many antineoplastic drugs, such as imidazopyrazines, morpholine imidazopyrazines; and it can be used as synthetic intermediates of organic compounds, such as imidazolidin substrates for alkanes. [0003] At present, there are few reports on the synthesis of 2-aminopyrazine derivatives, and there are some shortcomings, such as long route, large pollution, high cost, etc. The present invention discloses a synthetic method with simple operation, mild conditions, little pollution and low cost , which is conducive to large-scale production. Contents of the invention [0004] The technical problem to be solved by the present invention is to provide a method for synthesizing 2-aminopyrazine derivatives with readily available raw materials,...

Claims

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Application Information

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IPC IPC(8): C07D241/20C07D403/04
CPCC07D241/20C07D403/04
Inventor 刘明星姜卫东王晚霞
Owner HUBEI UNIV OF TECH
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