反应详情

The product of Step 12 (646 g, 1.58 mol) was dissolved in ethanol (5.17 L) and the solution filtered. A solution of L-lactic acid (142 g, 1.58 mol) dissolved in ethanol (2.59 L) was filtered and added to the solution of the filtered solution (above) and then to the mixture was added EtOAc (7.75 L). The suspension was stirred at RT for 12 h and then cooled to 5° C. for a further 2 h. The solid which had formed was removed by filtration, washed with EtOAc (2×2.58 L) and heptane (2×1.94 L) and dried to constant weight at 35° C. giving the title compound (581 g, 74% yield).

1. filtrationthe solution filtered
2. filtrationwas filtered
3. additionadded to the solution of the filtered solution (above)
4. additionto the mixture was added EtOAc (7.75 L)
5. temperaturecooled to 5° C. for a further 2 h
6. customThe solid which had formed
7. customwas removed by filtration
8. washwashed with EtOAc (2×2.58 L) and heptane (2×1.94 L)
9. customdried to constant weight at 35° C.