| 摘要 |
The present provides a process for preparing a compound of formula (3), the process comprising the steps of: (a) providing an aqueous acidic solution comprising a compound of formula (1) and, as an impurity, a compound of formula (2); and (b) treating the aqueous acidic solution of step (a) such that the compound of formula (2) dehydrates to form a compound of formula (1) and the compound of formula (1) is reduced to form an aqueous acidic solution of the compound of formula (3), wherein: the treating of step (b) is carried out at one or more temperatures greater than ambient in the presence of a hydrogenation catalyst and hydrogen gas; and wherein for the compounds of formulae (1), (2) and (3): i) R1 is -OH, R2 is-OH and R3-H; or ii) R1 is -OCH3, R2 is -H and R3 -CH3; or iii) R1 is-OH, R2 is-H and R3-CH3; or iv) R1, is -OCH3, R2 is -H and R3 -H; or v) R1, is -OH, R2is-H and R3-H; or vi) R1, is -OCH3, R2 is -OH and R3 -H. |
