1,3-Dibromo-5,5-dimethylhydantoin → HCID 131723313, compound

Participants

Reaction Steps

3β-tert-Butyldimethylsilyloxy-4,4-dimethylchol-5-en-24-oic acid methyl ester (9.75 g) is dissolved in a warm mixture of 122 ml of benzene and 475 ml of n-hexane, 1,3-dibromo-5,5-dimethylhydantoin (3.95 g) is added and the mixture is refluxed for 15 minutes. After cooling (fast) and evaporating to dryness under reduced pressure, 475 ml of o-xylene and 21.7 ml of quinaldine is added and the mixture is refluxed for 1 hour. After aqueous work-up and trituration with methanol 3β-tert-butyldimethylsilyloxy-4,4-dimethylchola-5,7-dien-24-oic acid methyl ester (8.22 g) is isolated. Melting point: 116-124° C. 1H-NMR (CDCl3, 300 MHz): δ=5.88 (1H, m); 5.52 (1H, m); 3.65 (3H, s); 3.32 (1H, m); 0.89 (9H, s); 0.04 (6H, m).

Provenance & Evidence