Thionyl Chloride → 4-Chloro-6,7-dimethoxyquinazoline

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Reaction Steps

4.12 g (20 mmol) of 6,7-dimethoxy-4-chloro-quinazolinone was placed in a 500 mL single-necked round-bottom flask, and then 120 mL of distilled thionyl chloride containing a drop of DMF was slowly added. The mixture was refluxed. After the completion of the reaction monitored by TLC, the excess amount of thionyl chloride was evaporated under reduced pressure. The residue was dissolved in 300 mL of ethyl acetate, and then washed to neutrality with saturated sodium bicarbonate solution. The organic layer was dried over anhydrous sodium sulfate, concentrated, and then purified by column chromatography (Vpetroleum ether:Vethyl acetate=4:1-2:1) to give 6,7-dimethoxy-4-chloro-quinazoline in 85% yield. 1H NMR (DMSO-d6, 400 MHz): 4.01 (s, 6H, 2CH3), 7.38 (s, 1H), 7.45 (s, 1H), 8.88 (s, 1H); ESI-MS (100%): 224 ((M)+, 100).

Provenance & Evidence