反应详情

Acid 1-3 (4.6 g, 20 mmol) was dissolved in 300 mL of a 1:1 mixture of methanol/toluene at 23° C. under N2 atmosphere. Trimethylsilyl diazomethane (20 mL, 40 mmol), added dropwise until color persisted and stirred for an additional 4 hours. Solvent was removed in vacuo and residue dried under vacuum for 1 hour. Residue was then redissolved in 300 mL methanol and placed under N2 atmosphere. NaBH4 (10 g, 264 mmol)and the reaction stirred for 4 hours. When complete, solvent was removed in vacuo and residue taken up in ethyl acetate and washed with water, brine and dried over MgSO4. SiO2 chromatography with 40% EtOAc/Hexanes gave 3.1 g of the product 1-4 as white crystals (71%) M.P. NMR CDCl3 (δ): 8.01 (2H, m); 7.44 (3H, m); 3.75 (2H, t, J=5.8, 11.4 Hz); 2.68 (2H, t, 6.8, 13.7 Hz); 2.35 (3H, s); 1.91 (2H, m).

1. customSolvent was removed in vacuo and residue
2. customdried under vacuum for 1 hour
3. dissolutionResidue was then redissolved in 300 mL methanol
4. customWhen complete, solvent was removed in vacuo and residue
5. washwashed with water, brine
6. dry with materialdried over MgSO4