ChemicalBook CAS DataBase List 2,5-Dichloropyrazine

2,5-Dichloropyrazine synthesis

10synthesis methods

Product Name:2,5-Dichloropyrazine
CAS Number:19745-07-4
Molecular formula:C4H2Cl2N2
Molecular Weight:148.98

374063-92-0 Synthesis

374063-92-0
219 suppliers
$7.00/250mg

19745-07-4
201 suppliers
$20.00/1g

912773-21-8
147 suppliers
$9.00/100mg

Yield:19745-07-4 72 g

Reaction Conditions:

with trichlorophosphate at 60; for 2 h;

Steps:

2.1 (1) Preparation of mixture of 2,5-dichloropyrazine and 2-chloro-5-bromopyrazine
Add 50 grams of 2-hydroxypyrazine to 250 milliliters of N,N-dimethyl sulfoxide, reduce the temperature to 10-12°C, add 74 grams of dibromohydantoin in batches, and after holding for 1 hour, add 500 milliliters of water to precipitate a large amount The yellow solid was filtered and dried to obtain 80.1 g of 2-hydroxy-5-bromopyrazine. Add 2-hydroxy-5-bromopyrazine to 341 grams of phosphorus oxychloride and heat up to 60°C for 2 hours, then pour it into 800 grams of ice-water mixture, filter, 350 ml of isopropyl acetate, extract and concentrate to obtain 72 Grams of dark brown oil is a mixture of 2,5-dichloropyrazine and 2-chloro-5-bromopyrazine. The total yield of the two steps is about 79%.

References:

Lanzhou Kangyuxin Biological Technology Co., Ltd.;Zhang Qiaolan CN111471025, 2020, A Location in patent:Paragraph 0067-0069

FullText

33332-29-5 Synthesis