Yield:50440-75-0 86%

Reaction Conditions:

with dimethylsulfone at 120 - 125; for 0.5 h;

Steps:

Preparation of 2,4-diamino-6-bromoquinazoline (1)

2-Amino-5-bromobenzonitrile (0.98g, 5mmol) and chloroformamidine hydrochloride (1.73g, 15mmol) were added to a 100mL three-necked flaskand dimethyl sulfone (15g, 160mmol), heated to 120-125°C, reacted for 30min, and a yellow solid was precipitated.Cool to room temperature, add distilled water to make it completely dissolved, adjust pH to 8-9 with concentrated ammonia water, and a large amount of yellow solid is precipitated.Filter, dry, and purify the crude product by column chromatography (eluent: CH2Cl2/CH3OH=95:5to 90:10, v/v) to obtain a yellow solid 0.95g, yield 86%,

References:

CN114230557,2022,A Location in patent:Paragraph 0058-0060