[Cl:1][C:2]1[CH:3]=[C:4]([C:8]2([CH:21]([C:27]#[N:28])[C:22]([O:24]CC)=[O:23])[CH2:13][CH2:12][N:11]([C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15])[CH2:10][CH2:9]2)[CH:5]=[CH:6][CH:7]=1.[OH-].[Na+].Cl>C(O)C>[C:17]([O:16][C:14]([N:11]1[CH2:12][CH2:13][C:8]([CH:21]([C:27]#[N:28])[C:22]([OH:24])=[O:23])([C:4]2[CH:5]=[CH:6][CH:7]=[C:2]([Cl:1])[CH:3]=2)[CH2:9][CH2:10]1)=[O:15])([CH3:20])([CH3:18])[CH3:19]A solution of 16b (5.2 g, 12.8 mmol) was dissolved in ethanol (30 ml) and 4 M aqueous sodium hydroxide (30 ml, 120 mmol) was added. The resulting solution was stirred at room temperature for 6.5 hours and then stored at 0° C. overnight. Concentrated hydrochloric acid (10 ml) was added dropwise at 0° C. and the mixture was then adjusted to pH˜4 with 1 M hydrochloric acid. The solution was extracted with ethyl acetate (500 ml) and the aqueous phase was acidified to pH˜3 and re-extracted with ethyl acetate. Both ethyl acetate layers were combined and washed with water and brine and then dried and concentrated to afford [1-(tert-butoxycarbonyl)-4-(3-chlorophenyl) piperidin-4-yl](cyano)acetic acid (16c) as a rigid foam (3.75 g, 77%). This material was used without further purification.
Wird geladen…
