反应详情

A solution of product from Step A (16.4 g, 0.1 mol), toluene (300 ml), p-toluenesulfonic acid (1.0 g) and ethylene glycol (20 ml) was heated at reflux with the aid of a Dean-Stark trap. After 6 hours, the organic layer was cooled, washed with saturated Na2CO3. The Na2CO3 layer was extracted with ethyl acetate (2x). The combined organic extracts were dried, filtered and concentrated to dryness. The residue was distilled at 149°-153° C. at 0.3 mm Hg to yield 16.4 g (79%) of product.

1. temperatureat reflux with the aid of a Dean-Stark trap
2. temperaturethe organic layer was cooled
3. washwashed with saturated Na2CO3
4. extractionThe Na2CO3 layer was extracted with ethyl acetate (2x)
5. customThe combined organic extracts were dried
6. filtrationfiltered
7. concentrationconcentrated to dryness
8. distillationThe residue was distilled at 149°-153° C. at 0.3 mm Hg