The present invention relates to a process for providing the compound of formula I, comprising the step of reacting a compound of formula VII with a base in the presence of an alkaline- or alkaline earth metal salt (MX), wherein LG is a leaving group. The presence of an alkaline- or alkaline earth metal salt was surprisingly found to render said reaction highly reliable in terms of the yield and purity of the compound of formula I obtained. In a further aspect, the present invention relates to the compound of formula I, having less than an amount of 1.50% or less than an amount of 1.25% or less than an amount of 1.00% or less than an amount of 0.75% or less than an amount of 0.50% or less than an amount of 0.25% or less than an amount of 0.10% of the compound of formula VIII.
本发明涉及一种提供式 I 化合物的工艺,包括在碱或碱土
金属盐 (MX) 存在下使式 VII 化合物与碱反应的步骤,其中 LG 为离去基团。令人惊讶的是,碱
金属或碱土
金属盐的存在使所述反应在所获得的式 I 化合物的产率和纯度方面具有高度可靠性。在另一个方面,本发明涉及式 I 化合物,其式 VIII 化合物的含量小于 1.50%或小于 1.25%或小于 1.00%或小于 0.75%或小于 0.50%或小于 0.25%或小于 0.10%。