7-bromopyrrolo[1,2-f][1,2,4]triazin-4-amine synthesis

Yield:937046-98-5 91%

Reaction Conditions:

with 1,3-dibromo-5,5-dimethylimidazolidine-2,4-dione at -15 - -10; for 0.75 h;Large scale;

Steps:

5 The specific preparation method is:
Add 1000g of intermediate IV (7.45mol, 1.0eq) to a 20L three-necked bottle, add 10L of solvent, stir evenly, and lower the temperature to -15 ° C to obtain the reaction liquid for use;Dissolve 1065.7g of bromination reagent in 2L of solvent and slowly drop it into the reaction solution.Keep the temperature in the three-necked flask below -10 ° C and react for 45 minutes. After the reaction was monitored by TLC, 15 L of a 25% sodium sulfite solution was added to precipitate a solid.Filter with suction, wash the filter cake with water, dissolve and separate with a molar ratio of 1: 1 ethyl acetate and 5% sodium carbonate solution, and use a sodium carbonate solution for the organic phase.After washing with brine, drying, separation and concentration to obtain 1450 g of white solid, which is the final product (7-bromopyrrolo [2,1-f] [1,2,4] thiazin-4-amine).The purity of the final product is 97%, the yield is 91%, which contains 1.2% of the dibromide by-product. Among them, the reaction progress was monitored using TLC, and the developing agent used in the monitoring reaction was a mixed liquid of polyethylene and ethyl acrylate, and the molar ratio of polyethylene to ethyl acrylate was 3: 1.The bromination reagent added is one of N-bromosuccinimide, dibromohydantoin and NBS. In this embodiment, dibromohydantoin is preferably used. Other bromination reagents can also be selected without affecting the reaction product.The added solvent is one of anhydrous DMF, dichloromethane, and tetrahydrofuran; in this embodiment, anhydrous DMF is preferably used, and other bromination reagents can also be selected without affecting the reaction product.The molar ratio of intermediate IV to bromination reagent is 1.0: 0.5-1.5.

References:

Chengdu Aofei Biochemical Pin Co., Ltd.;Zhang Zhuo;Shen Mao;Zhao Linji CN110845502, 2020, A Location in patent:Paragraph 0058-0064

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