反应详情

A stirred mixture of the compound of product of Step 3 (0.200 g, 0.549 mmol) in acetone (5.3 mL), under nitrogen, is treated first with 5% aqueous sodium carbonate (5.3 mL) and then, dropwise during 3minutes with a solution of p-toluenesulfonyl chloride (0.16 g, 0.82 mmol) in acetone (2.7 mL). Initially this mixture is a two phase solution; however, after about 25minutes a precipitate began to form. It is kept at ambient temperature (23° C.) for 4 hours and filtered. The filtrate is concentrated under reduced pressure to remove acetone and the aqueous residue is extracted with CH2Cl2. The extract is dried (MgSO4) and concentrated to give a small amount of crude product. Most of the product is in the aqueous layer which is concentrated in vacuo. The residue is combined with the crude product from the CH2Cl2 extract and chromatographed on silica gel with mixtures of MeOH--NH4OH--CH2CI2 that continued 3-5% MeOH and 0.3-0.5% NH4OH. The product is crystallized from MeOH--EtOAc to give the title compound. mp 140-146° C.;

1. customto form
2. customis kept at ambient temperature
3. custom(23° C.)
4. customfor 4 hours
5. filtrationfiltered
6. concentrationThe filtrate is concentrated under reduced pressure
7. customto remove acetone
8. extractionthe aqueous residue is extracted with CH2Cl2
9. dry with materialThe extract is dried (MgSO4)
10. concentrationconcentrated
11. customto give a small amount of crude product
12. concentrationis concentrated in vacuo
13. extractionextract
14. customchromatographed on silica gel with mixtures of MeOH
15. customThe product is crystallized from MeOH