反应详情

10.03 g of the product from stage 4 were dissolved with stirring in 200 ml of semi-concentrated sodium hydroxide solution at a temperature of 20° C. The pH was then adjusted to 4 with concentrated hydrochloric acid and extracted three times with 50 ml portions of dichloromethane. The extracts were washed once with a saturated sodium chloride solution and dried over sodium sulphate. Once the solvent had been removed by distillation, 8.48 g of 2-propyl-2-(3-thiazol-2-ylureido)pentanoic acid (93% of th.) were obtained in the form of white crystals (mp 154-155° C.).

1. extractionextracted three times with 50 ml portions of dichloromethane
2. washThe extracts were washed once with a saturated sodium chloride solution
3. dry with materialdried over sodium sulphate
4. customOnce the solvent had been removed by distillation