反应详情

To a solution of 2-chlorothiazole-5-carboxaldehyde (Example 53; 378 mg, 2.6 mmol) in aqueous tetrahydrofuran (9.75 mL tetrahydrofuran, 0.25 mL of water, 40:1) at 25° C. was added piperazine (0.55 g, 6.4 mmol) followed by lithium hydroxide (129 mg, 3.0 mmol). After stirring for 24 h at room temperature, the solvents were removed under reduced pressure. The residual solid was diluted with water (50 mL) and neutralized to pH 7 with 1N hydrochloric acid solution. The resulting solids were filtered, washed with water, dried under vacuum and flash chromatographed (silica gel, 10% methanol in dichloromethane) to yield 2-(piperazin-1-yl)thiazole-5-carboxaldehyde (191 mg, 38% yield) as a yellow solid.

1. customthe solvents were removed under reduced pressure
2. additionThe residual solid was diluted with water (50 mL)
3. filtrationThe resulting solids were filtered
4. washwashed with water
5. customdried under vacuum and flash
6. customchromatographed (silica gel, 10% methanol in dichloromethane)