1alpha,3beta-Bis(methoxycarbonyloxy)pregna-5,7-diene-20-carboxylic acid → Methyl 1alpha,3beta-bis(t-butyldimethylsilyloxy)pregna-5,7-diene-20-carboxylate
Reaktionsgleichung
[Si:1]([O:8][C@@H:9]1[C@@:30]2([CH3:31])[C:13](=[CH:14][CH:15]=[C:16]3[C@@H:29]2[CH2:28][CH2:27][C@@:26]2([CH3:32])[C@H:17]3[CH2:18][CH2:19][C@@H:20]2[CH:21]([C:23]([OH:25])=[O:24])[CH3:22])[CH2:12][C@@H:11]([O:33][Si:34]([C:37]([CH3:40])([CH3:39])[CH3:38])([CH3:36])[CH3:35])[CH2:10]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].[CH3:41]OC(O[C@@H]1[C@@]2(C)C(=CC=C3[C@@H]2CC[C@@]2(C)[C@H]3CC[C@@H]2C(C(O)=O)C)C[C@@H](OC(OC)=O)C1)=O>>[Si:1]([O:8][C@@H:9]1[C@@:30]2([CH3:31])[C:13](=[CH:14][CH:15]=[C:16]3[C@@H:29]2[CH2:28][CH2:27][C@@:26]2([CH3:32])[C@H:17]3[CH2:18][CH2:19][C@@H:20]2[CH:21]([C:23]([O:25][CH3:41])=[O:24])[CH3:22])[CH2:12][C@@H:11]([O:33][Si:34]([C:37]([CH3:39])([CH3:38])[CH3:40])([CH3:35])[CH3:36])[CH2:10]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2]Komponenten
3
Versuchsvorschrift
The procedure of Example 7 was repeated except that 112 mg of 1α,3β-bis(t-butyldimethylsilyloxy)pregna-5,7-diene-20-carboxylic acid obtained in Example 23 was used in lieu of 85 mg of 1α,3β-bis(methoxycarbonyloxy)pregna-5,7-diene-20-carboxylic acid to give 91 mg of methyl 1α,3β-bis(t-butyldimethylsilyloxy)pregna-5,7-diene-20-carboxylate.