Imidazole → HCID 69412991, compound

Participants

Reaction Conditions

Reaction Steps

3β-Hydroxy-4,4-dimethylchol-5-en-24-oic acid methyl ester (19.1 g) is suspended in 390 ml of N,N-dimethylformamide (hereinafter designated DMF) and 39 g of imidazol and 34.6 g of tert-butyldimethylsilyl choride is added. The reaction mixture is stirred at 70° C. for 20 hours. After aqueous work-up, a crude product 23.9 g is isolated. Crystallization from tetrahydrofurane/methanol (hereinafter tetrahydrofurane and methanol are designated THF and MeOH, respectively) yields 3β-tert-butyldimethylsilyloxy-4,4-dimethyl-chol-5-en-24-oic acid methyl ester (19.55 g). Melting point: 144-146° C. 1H-NMR (CDCl3, 300 MHz): δ=5.52 (1H, m); 3.66 (3H, s); 3.18 (1H, m); 0.89 (9H, s); 0.02 (6H, m).

Provenance & Evidence