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Synthetic method of 2-amino-3,5-dichloropyridine

A dichloropyridine and synthetic method technology, applied in the direction of organic chemistry, etc., can solve the problems of many by-products, high price, low product yield, etc., and achieve the effects of moderate reaction conditions, easy control of the reaction, and high product purity

Active Publication Date: 2014-09-03
陕西友帮生物医药科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] (1) There are many by-products, resulting in a darker color of the product, which is difficult to refine and purify
Although it can be recrystallized multiple times with organic solvents, the quality still cannot meet the high requirements, and repeated crystallization leads to low product yield, increased cost, and cumbersome operation;
[0005] (2) The chemical reduction method used has serious corrosion of equipment and environmental pollution, and its development has been restricted at present;
[0006] (3) The source of raw materials is limited, the price is expensive, and the operation is troublesome;
[0007] (4) Need to use noble metal catalyst, increased preparation cost

Method used

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  • Synthetic method of 2-amino-3,5-dichloropyridine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019]

[0020] In a 100ml round-bottom single-necked flask, add 45ml of a mixed solvent with a volume ratio of DMF and methanol of 1:1.5, insert a thermometer, start a magnetic stirrer, and add 12.8g of 2-amino-5-chloropyridine, add N- 6.75 g of chlorosuccinimide was reacted under stirring at 15° C. for 5 hours. TLC and GC confirmed the completion of the reaction. The solvent was removed by rotary evaporation to obtain the crude product, which was separated by silica gel column chromatography to obtain the pure product 2-amino-3,5-dichloropyridine. After drying, the calculated yield was 53.1%, and the purity was 96.28% (GC). NMR analysis: 1HMR (CDCl3) 400MHz: δ7.94 (s, 1H); δ7.51 (s, 1H); δ4.93 (bs, 2H). Melting point 80°C-84°C (79°C-83°C in literature).

Embodiment 2

[0022] Add 700ml of a mixed solvent of DMF and methanol at a volume ratio of 1.5:1 to a 2L round-bottom single-necked flask, insert a thermometer to start a magnetic stirrer, and add 169.7g of 2-amino-5-chloropyridine, N-chloro 264.4 g of succinimide was reacted with stirring at 0° C. for 8.5 hours. TLC and GC confirmed the completion of the reaction. The solvent was removed by rotary evaporation to obtain a crude product, and the pure product 2-amino-3,5-dichloropyridine was obtained by ethyl acetate. After drying, the calculated yield was 55.5%, and the purity was 98.50% (GC). Melting point 81°C-84°C (79°C-83°C in literature).

[0023]

Embodiment 3

[0025] Add 5500ml of a mixed solvent of DMF and methanol at a volume ratio of 2.5:1 to a 10L round-bottomed three-neck flask, insert a thermometer and install a condensation reflux device, start a magnetic stirrer, and add 2560.8g of 2-amino-5-chloro Pyridine, N-chlorosuccinimide 6118.4g, stirred and reacted at 45°C for 2.5 hours. TLC and GC confirmed the completion of the reaction. The solvent was removed by rotary evaporation to obtain a crude product, which was recrystallized from ethanol to obtain the pure product 2-amino-3,5-dichloropyridine. After drying, the calculated yield was 70.5%, and the purity was 98.20% (GC). Melting point 80°C-84°C (79°C-83°C in literature).

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Abstract

The invention belongs to the field of organic synthesis and in particular relates to a synthetic method of 2-amino-3,5-dichloropyridine. The synthetic method comprises the following steps: reacting raw materials including 2-amino-5-chloropyridine and N-chlorosuccinimide for 0.5-24 hours in a molar weight of 1: (0.5-5) in a proper solvent at 0-100 DEG C to generate a 2-amino-3,5-dichloropyridine crude product and purifying to obtain the pure product 2-amino-3,5-dichloropyridine. The synthetic method has the beneficial effects that the reaction raw materials are available and are reasonable in prices; meanwhile, heavy metals and corrosive gases are not used in the preparation reaction; the reaction is mild; the synthetic method does not have special requirements for reaction equipment and common corrosion resistant equipment can be used for production; besides, with the advantageous conditions such as moderate reaction conditions, easily controlled reaction and high product purity, and the process is easy to popularize.

Description

(1) Technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a synthesis method of 2-amino-3,5-dichloropyridine. (2) Background technology [0002] 2-Amino-3,5-dichloropyridine is an important intermediate in organic synthesis, mainly used in pharmaceutical intermediates, organic synthesis, organic solvents, and can also be used in dye production, pesticide production and spices. [0003] The preparation of existing 2-amino-3,5-dichloropyridine has the following disadvantages: [0004] (1) There are many by-products, resulting in a darker color of the product, which is difficult to refine and purify. Although organic solvents can be used to recrystallize multiple times, the quality still cannot meet the high requirements, and repeated crystallization leads to low product yield, increased cost, and cumbersome operation; [0005] (2) The chemical reduction method used has serious corrosion of equipment and environmental pol...

Claims

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Application Information

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IPC IPC(8): C07D213/73
CPCC07D213/73
Inventor 付锐曹惊涛来新胜
Owner 陕西友帮生物医药科技有限公司
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