| 摘要 |
This invention relates to a process for preparing the compound having formula (I) which comprises i) heating the compound of formula (VII) wherein R<3> is R<4> or benzyl and R<4> is R<5>C(=O), R<5>OC(=O) or R<5>SO2 wherein R<5> is (C1-C6)alkyl or (C6-C10)aryl(C1-C6)alkyl; at an elevated temperature in the presence of a base with the proviso that when R<3> in the resultant product is R<4> said product is ii) further treated with an aqueous mineral acid at an elevated temperature followed by iii) treatment of the product of ii) with a) a benzylating agent in the presence of a base or b) benzaldehyde in the presence of a reducing agent and an acid. |
