[CH3:1][C:2]1[O:6][C:5]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)=[N:4][C:3]=1[CH2:13][CH2:14][C:15](O)=[O:16].C[Si](C=[N+]=[N-])(C)C.[BH4-].[Na+]>CO.C1(C)C=CC=CC=1>[CH3:1][C:2]1[O:6][C:5]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)=[N:4][C:3]=1[CH2:13][CH2:14][CH2:15][OH:16]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).
Wird geladen…
