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Preparation method of 2-cyano-5-bromopyridine

A technology of bromopyridine and cyano, which is applied in the field of preparation of 2-cyano-5-bromopyridine, can solve the problems of difficult purification of the target product, high cost of raw materials, cumbersome operation, etc., to facilitate purification treatment, improve purity and The effect of high yield, purity and yield

Active Publication Date: 2021-11-05
黑龙江立科新材料有限公司
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Problems solved by technology

At present, the synthetic route of 2-cyano-5-bromopyridine mainly contains: (1) take 2.5-dibromopyridine as raw material, generate 2-cyano-5-bromopyridine under the action of cyanide reagents such as sodium cyanide and cuprous cyanide; 5-bromopyridine (such as the synthetic route shown in the reaction formula 1 disclosed in document US2003 / 87906, EuropeanJournal of Medicinal Chemistry2011, Journal of Medicinal Chemistry (2003vol.46#22p), this synthesis process can produce a large amount of dicyanopyridine By-products make the purification of the target product difficult, with low purity and low yield; (2) use 2-formyl-5-bromopyridine as raw material, react with hydroxylamine to generate oxime, and then generate cyano through dehydration to obtain 2- Cyano-5-bromopyridine (synthesis route shown in reaction formula 2 disclosed in Journal of Organic Chemistry (2008vol.73#23p), Bioorganic and Medicinal Chemistry Letters (2006vol.16#5p)), the synthetic process raw material The cost is high and not easy to obtain, and there are also defects such as long routes and cumbersome operations

Method used

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  • Preparation method of 2-cyano-5-bromopyridine
  • Preparation method of 2-cyano-5-bromopyridine
  • Preparation method of 2-cyano-5-bromopyridine

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preparation example Construction

[0021] The preparation method of the 2-cyano-5-bromopyridine of the present invention comprises: subjecting 2-nitro-5-bromopyridine to a cyanide reagent for a substitution reaction to obtain 2-cyano-5-bromopyridine. In the preparation process, 2-nitro-5-bromopyridine undergoes a substitution reaction with a cyanide reagent, mainly in a nucleophilic substitution manner, so that the nitro (-NO) in 2-nitro-5-bromopyridine 2 ) is replaced by the cyano group (-CN) in the cyanide reagent, thereby generating 2-cyano-5-bromopyridine, the synthetic process is shown as follows:

[0022]

[0023] In the present invention, 2-nitro-5-bromopyridine is used as raw material which is cheap, easy to obtain and widely sourced, and is subjected to a substitution reaction with a cyanide reagent to obtain 2-cyano-5-bromopyridine, which has low cost , the route is short, the operation is simple, and the generated nitrite by-product is easily soluble in water, which is convenient to remove, which ...

Embodiment 1

[0036] Add 507.5mL sulfolane, 101.5g (0.5mol, 1.0eq) 2-nitro-5-bromopyridine, 24.5g (0.55mol, 1.1eq) to a 2000mL four-necked flask equipped with a mechanical stirrer, a thermometer, and a condenser Sodium cyanide, under the protection of nitrogen, the oil bath of the mixed system obtained was heated up to 150°C, and stirred and reacted at 150°C for 4 hours (the HPLC detection was carried out by sampling, and the amount of 2-nitro-5-bromopyridine in the reaction system The concentration is less than 1.0%, the concentration of 2.5-dicyanopyridine is less than 1.0%); the oil bath is removed, the system is lowered to 20-30°C by a water bath, then 507.5ml of water and 507.5ml of ethyl acetate are added to the system, and stirred for 0.5 hour, stand still for 0.5 hour, separate layers, separate the water phase and the organic phase, adopt 254ml ethyl acetate to extract the water phase, the organic phases obtained are combined; then use 507.5ml water to wash the combined organic phase...

Embodiment 2～ Embodiment 6

[0042] The difference between embodiment 2~embodiment 6 and embodiment 1 is that the consumption of sodium cyanide is different (specifically see table 1, except the difference shown in table 1, all the other conditions are basically the same as embodiment 1).

[0043] Table 1

[0044] Example Sodium cyanide dosage Product: raw material: dicyanide 2-nitro-5-bromopyridine product quality HPLC purity / % yield Example 1 24.5g (1.0eq) 48：0.3：0.25 77g ＞99％ 84.15％ Example 2 19.6g (0.8eq) 14：1：0 71.6g 97.8％ 78.25％ Example 3 22.05g (0.9eq) 35：1：0 73.3g 98.5％ 80.12％ Example 4 25.725g (1.05eq) 48：0.25：0.25 77.8g 99.2％ 85.03％ Example 5 26.95g (1.1eq) 48：0.25：0.5 72.4g 98.7％ 79.13％ Example 6 29.4g (1.2eq) 32：0：1 67.4g 96.3％ 73.67％

[0045] "*" means "product: raw material: dicyanide" means that 2-cyano-5-bromopyridine, 2-nitro-5-bromopyridine, 2.5-dicyanide are obtained from 2-nitro-5-bromopyridine Th...

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Abstract

The invention provides a preparation method of 2-cyano-5-bromopyridine, which comprises the following step: carrying out substitution reaction on 2-nitro-5-bromopyridine and a cyaniding reagent to obtain the 2-cyano-5-bromopyridine. According to the method, the 2-nitro-5-bromopyridine which is low in price, easy to obtain and wide in source is used as a raw material and is subjected to substitution reaction with the cyaniding reagent to prepare the 2-cyano-5-bromopyridine, the process is low in cost, short in route and simple to operate, the generated nitrite byproduct is easy to dissolve in water and convenient to remove, purification treatment of the target product is facilitated, and the purity and the yield of a target product can be obviously improved.

Description

technical field [0001] The invention relates to a preparation method of 2-cyano-5-bromopyridine, belonging to the field of organic synthesis. Background technique [0002] 2-cyano-5-bromopyridine is an important chemical intermediate, which is widely used in the fields of medicinal chemistry, organic synthesis and material chemistry. At present, the synthetic route of 2-cyano-5-bromopyridine mainly contains: (1) take 2.5-dibromopyridine as raw material, generate 2-cyano-5-bromopyridine under the action of cyanide reagents such as sodium cyanide and cuprous cyanide; 5-bromopyridine (such as the synthetic route shown in the reaction formula 1 disclosed in document US2003 / 87906, EuropeanJournal of Medicinal Chemistry2011, Journal of Medicinal Chemistry (2003vol.46#22p), this synthesis process can produce a large amount of dicyanopyridine By-products make the purification of the target product difficult, with low purity and low yield; (2) use 2-formyl-5-bromopyridine as raw mat...

Claims

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Application Information

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IPC IPC(8): C07D213/84
CPCC07D213/84
Inventor 姜魁
Owner 黑龙江立科新材料有限公司
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