反应详情

A solution of trifluoroacetic acid (TFA; 6 mL) in dichloromethane (24 mL) was added to a stirred solution of the product of step 1 above (5.79 g, 19.4 mmol) in dichloromethane (20 mL) at 0° C. After 1 h and 1.5 h of stirring, additional portions (10 mL and 5 mL) of TFA were added. Crushed ice and 5 M aqueous NaOH were added and the mixture was extracted with dichloromethnae (12×200 mL). The combined organic layers were dried (K2CO3), filtered and concentrated in vacuo. This furnished 3.48 g (90%) of the title compound as a light yellow solid. *Previously described in a) J. Med. Chem. 1978, 21, 536-542; b) U.S. Pat. No. 4,082,844

1. extractionthe mixture was extracted with dichloromethnae (12×200 mL)
2. dry with materialThe combined organic layers were dried (K2CO3)
3. filtrationfiltered
4. concentrationconcentrated in vacuo