Unlock instant, AI-driven research and patent intelligence for your innovation.

Synthesis of 3, 5-dibromo-4-iodopyridine

A technology of iodopyridine and tribromopyridine, which is applied in the field of synthesis of halopyridines, can solve the problems of difficult large-scale production, difficult separation and purification, and low yield, and achieve good economic and social benefits, good reaction selectivity, The effect of high reaction yield

Inactive Publication Date: 2014-03-26
XIHUA UNIV
View PDF0 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

3,5-dibromo-4-iodopyridine is relatively difficult to synthesize, and there are few reports on the synthesis of 3,5-dibromo-4-iodopyridine at home and abroad, only literature (Chemistry--A European Journalvol. 17; nb. 47; 2011; p. 13284 - 13297) disclosed its synthesis method: using 3,5-dibromopyridine as raw material, tetrahydrofuran and n-hexane as solvent, and n-butyl Lithium base and tetramethylethylenediamine zinc dichloride react to generate active carbanion intermediates, which react with iodine at room temperature to generate 3,5-dibromo-4-iodopyridine, and react The yield was only 8% (22% 3,5-dibromo-2-iodopyridine isomer was generated), and the isomer 3,5-dibromo-2-iodopyridine appeared in the product, making separation, Difficult to purify
In this reaction, a large amount of expensive n-butyllithium (the molar ratio of n-butyllithium to 3,5-dibromopyridine is 1.5:1), makes the production cost high; at the same time, the use of n-butyllithium makes The process has harsh operating conditions without water and oxygen, and the engineering is difficult
In summary, the prior art has problems that need to be solved, such as low yield, a large number of isomers appearing in the product, making separation and purification difficult, harsh operating conditions, and difficult to achieve large-scale production.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Synthesis of 3, 5-dibromo-4-iodopyridine
  • Synthesis of 3, 5-dibromo-4-iodopyridine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025]

[0026] Synthesis of 3,5-dibromo-4-aminopyridine: Add solvent carbon tetrachloride 900ml, 4-aminopyridine 94.11g (1.0mol), azobisisobutyronitrile (AIBN) in sequence in a 2000ml three-necked flask 0.82g, N-bromosuccinimide (NBS) 391.56g (2.2mol) was added in batches at 20°C, and reacted at room temperature for 24 hours. The raw material 4-aminopyridine and the intermediate 3- After all the bromo-4-aminopyridines were converted into the target product 3,5-dibromo-4-aminopyridine, the reaction was stopped. Post-reaction treatment: After stirring the reaction solution and cooling it to room temperature, pour it into 1000ml carbon tetrachloride, stir, filter, wash the filter cake twice with 2*200ml carbon tetrachloride, and wash the filtrate once with aqueous sodium bicarbonate solution. Wash once with saturated brine, remove the solvent carbon tetrachloride by rotary evaporation, obtain the crude product of 3,5-dibromo-4-aminopyridine, recrystallize with n-hexane to obt...

Embodiment 2

[0028] Synthesis of 3,5-dibromo-4-iodopyridine:

[0029] Synthesis of 3,4,5-tribromopyridine by diazotization reaction: Add 400ml of 48% hydrobromic acid into a 1000ml three-necked flask, and add 3,5-dibromopyridine synthesized by the method in Example 1 above in batches at 25°C - 126.0g (0.50mol) of 4-aminopyridine, stir well to dissolve it, cool the reaction bottle to 0°C with an ice-salt bath, slowly add dropwise a sodium nitrite solution containing 38.5g (0.56mol) sodium nitrite and 150g water , the dropwise addition process temperature control 0 ~ 3 ℃, maintain the temperature after the dropwise addition, stir for 1 hour, remove the ice-salt bath, stir overnight at room temperature, pour the reaction solution into ice water, stir well, and use 10% sodium hydroxide aqueous solution Neutralize to pH=6.2, add extractant chloroform 2*300ml, extract twice, separate the liquid, adjust the combined extract to pH=7.5 with 5% sodium hydroxide aqueous solution, separate the liquid,...

Embodiment 3

[0032] In the diazotization reaction, the concentration of hydrobromic acid is 35%, and others are the same as in operation example 2.

[0033] According to the operation in Example 2, 121.8 g of pure white 3,5-dibromo-4-iodopyridine was obtained, with a yield of 67.2% and a content of 98.1%.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a synthesis method of halogenated pyridine 3, 5-dibromo-4-iodopyridine, wherein 4-aminopyridine is taken as an initial material and is subjected to bromination reaction to produce 3, 5-dibromo-4-aminopyridine; and the 3, 5-dibromo-4-aminopyridine is subjected to diazo-reaction to obtain a 3, 4, 5-tribromo pyridine midbody, and the midbody is subjected to halogen exchange reaction to obtain the 3, 5-dibromo-4-iodopyridine. The process route has the characteristic of being simple in operation, the yield is high, the product quality is good, the initial material acquisition is easy and the like.

Description

technical field [0001] The present invention relates to a synthetic method of halogenated pyridine, especially a synthetic method of 3,5-dibromo-4-iodopyridine. Background technique [0002] Halopyridines are important fine chemical intermediates and are widely used in the fields of medicine and pesticides. Halogenated pyridines containing bromine and iodine are widely used in the fields of pesticides, medicines, and functional materials. 3,5-dibromo-4-iodopyridine is relatively difficult to synthesize, and there are few reports on the synthesis of 3,5-dibromo-4-iodopyridine at home and abroad, only literature ( Chemistry--A European Journalvolume . 17; nb. 47; 2011; p. 13284 - 13297) disclosed its synthesis method: using 3,5-dibromopyridine as raw material, tetrahydrofuran and n-hexane as solvents, and n-butyllithium and Tetramethylethylenediamine zinc dichloride reacts to generate a lively carbanion intermediate, which reacts with iodine at room temperature to generate...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/61
Inventor 杨维清倪小惠胡伟发张园园马梦林
Owner XIHUA UNIV