[C:1]([C:4]1([C:11]([O:13][CH2:14][CH3:15])=[O:12])[CH2:9][CH2:8][C:7](=[O:10])[CH2:6][CH2:5]1)(=[O:3])[CH3:2].[CH:16](OC)(OC)OC.Cl>CO>[CH3:16][O:10][C:7]12[CH2:8][CH2:9][C:4]([C:11]([O:13][CH2:14][CH3:15])=[O:12])([CH2:5][CH2:6]1)[C:1](=[O:3])[CH2:2]2To a stirred solution of Step 3 product (1 eq) and trimethyl orthoformate (4.00 eq) in MeOH (9.4 v/w) at 5° C. was bubbled HCl gas (approximately 5 eq) over 2 hours, maintaining a pot temperature of 5° C. Upon complete addition, the reaction mixture, under nitrogen, was heated to, and stirred at, reflux for 30 minutes.
Wird geladen…