The reversible nature of the protonation and deprotonation sequence among the conjugated dienes implicated in the acid-catalysed double bond migration of steroid 5,7-dienes to 8,14-dienes allowed a high incorporation of deuterium atoms into the 5α-steroid 8,14-dienes. Treatment of cholesta-5,7-dien-3β-ol with a 37% deuterium oxide solution of deuterium chloride in refluxing O-deuterioethanol for 5 h afforded [5

The applicability of ultra-high performance liquid chromatography (UHPLC) for real-time analysis of a synthetic process was examined. A reduction reaction was selected as a model process. Quantities of acetophenone (AcPh) and phenyl ethanol (PhEt) in reaction solutions were analyzed at 5-and 15-min intervals. Reaction solutions were diluted using acetonitrile and subsequently filtered. A mixture of acetonitrile and water (6:4) was used as the mobile phase. PhEt and AcPh were detected at 0.64 and 0.75 min, respectively. Additionally, as many as nine different impurities were detected in the reaction solution. Given the ability to detect impurities in a reaction solution within a few minutes, UHPLC technology is deemed applicable for real-time synthetic process control.