6-BROMO-2,4-DICHLOROQUINAZOLINE

It is an important raw material and intermediate used in organic synthesis, pharmaceuticals, agrochemicals and dyestuff.

The synthesis of 6-BROMO-2,4-DICHLOROQUINAZOLINE is as follows:BTC (0.65 g, 2.2 mmol in 6mL of PhCl) was added to astirred solution of tris(4-methoxyphenyl)phosphine oxide 3d(0.33 g, 0.9 mmol in 5mL PhCl) dropwise in a round botttomflask placed on an ice bath. After complete addition,the mixture was stirred for 30 min at room temperature.Then isatin-3-oximes (3 mmol) were added, and the mixturewas heated to 120 C until completion of the reaction(followed by TLC, n-hexane/ethyl acetate 10:1). Aftercooling, the mixture was then poured into 50mL ice waterand extracted with ethyl acetate (320 mL). The organiclayer was dried over anhydrous Na₂SO₄ and concentrated invacuo. The crude product was purified over column chromatography(n-hexane/ethyl acetate 10:1) to afford thepure produce 2,4-dichloroquinazolins. Tris(4-methoxyphenyl)phosphine oxide 3d was recovered by column chromatography(n-hexane/ethyl acetate 1:1).