反应详情

温度

75 °C

A suspension of 8-iodo-3-methyl-2-(methylthio)quinazolin-4(3H)-one (700a; 15 g, 45.2 mmol) in 400 mL of DCM was set stirring at 0° C. before adding 3-chlorobenzoperoxoic acid (15.59 g of 77% max. Aldrich, 70 mmol) portion wise over 10 min. The ice bath was removed; and the reaction mixture was stirred at RT for 30 min. It was diluted with 200 mL of DCM, washed sequentially with ice cold 2×50 mL of saturated Na2CO3 followed by sat. Na2SO3 solution and 15 mL of brine. The organic solution was dried over Na2SO4, filtered, and concentrated under reduced pressure to give yellow crystalline solid (700b) containing a mixture of 8-iodo-3-methyl-2-(methylsulfinyl)quinazolin-4(3H)-one and 8-iodo-3-methyl-2-(methylsulfonyl)quinazolin-4(3H)-on. The crude material of yellow crystalline solid (700b) in 40 mL of THF and 40 mL of water at RT was treated with LiOH—H2O (6.60 g, 275 mmol). The reaction mixture was stirred in an oil bath at 75° C. for 2.5 h. It was concentrated to half of its volume under reduced pressure. The precipitated solid was filtered, rinsed with 2×5 mL of water followed by 2×5 mL of ether. The off-white crystalline solid was dried in a vacuum oven at 45° C. for 48 h to give 2-hydroxy-8-iodo-3-methylquinazolin-4(3H)-one (700c; 12.79 g, 42.3 mmol, 94% yield). The crude material was used in the next step. m/z (ES, +ve) 302.9 (M+H)+.

1. additioncontaining
2. concentrationIt was concentrated to half of its volume under reduced pressure
3. filtrationThe precipitated solid was filtered
4. washrinsed with 2×5 mL of water
5. customThe off-white crystalline solid was dried in a vacuum oven at 45° C. for 48 h