A process for preparing a compound of formula (22), comprising reducing a compound of formula (21), to produce a compound of formula (23), followed by the hydrogenolysis of the compound of formula 23 in a solvent comprising a C
1
to C
6
alkyl sulfonic acid and optionally a chlorinated solvent.
一种制备化合物公式(22)的方法,包括还原公式(21)的化合物,以产生公式(23)的化合物,随后在溶剂中进行公式23的氢解,所述溶剂包括C1到C6烷基
磺酸和可选的
氯化溶剂。