The invention relates to an industrial preparation method of an intermediate 5alpha-
androstane-2-ene-17
ketone, the intermediate is a
rocuronium bromide intermediate, and the method comprises the following steps: taking
epiandrosterone as a starting material, and reacting with paratoluensulfonyl
chloride to obtain a compound I; and carrying out
elimination reaction on the compound I in organic alkali or a DBU catalyst to obtain the compound 5 alpha-
androstane-2-ene-17
ketone. The method is good in
elimination reaction selectivity, high in yield, good in quality, low in cost, mild in reaction condition, short in production period, recyclable in reaction
solvent and green and environment-friendly in production process, and a single
impurity of the product is less than 0.3%.