反应详情

The aqueous phase of the hydrolysis reaction was acidified to pH of 2.0 with conc. HCl forming a white precipitate of (S)-chroman-2-carboxylic acid. The S-acid was extracted into toluene, and the phases were separated. The organic layer was placed in a vessel suitable for acid catalyzed esterification. Sulfuric acid was added to the vessel, and the mixture was heated to reflux. Water was removed by azeotropic distillation. The conversion of the acid to the ester was followed by GC analysis. Isobutyl (S)-chroman-2-carboxylate was thereby formed. Upon completion of the esterification, the sulfuric acid catalyst used in the reaction was removed by washing the reaction product with saturated sodium carbonate, and the S-carboxylate product was azeotropically dried again.

1. customThe aqueous phase of the hydrolysis reaction
2. extractionThe S-acid was extracted into toluene
3. customthe phases were separated
4. customThe organic layer was placed in a vessel suitable for acid
5. additionSulfuric acid was added to the vessel
6. temperaturethe mixture was heated to reflux
7. customWater was removed by azeotropic distillation