摘要
以二氟乙酸乙酯为原料,经Claisen酯缩合、乙氧亚甲基化、环化、水解反应合成了1-甲基-3-(二氟甲基)-1H-吡唑-4-羧酸,并优化了反应条件。优化反应条件下,总收率≥44%,纯度≥99%。中间体及产物结构经^(1)H NMR、 MS确认。该工艺操作简单,条件温和。
3-(Difluoromethyl)-1-methyl-1 H-pyrazole-4-carboxylic acid was prepared using ethyl difluoroacetate as starting material through a series of reactions including ester condensation reaction, ethoxylation, cyclization,and hydrolysis reaction. Its structure was conformed by 1H NMR and MS. Under the optimal reaction conditions,the total yield was over 44% based on the amount of ethyl difluoroacetate used while the purity was up to 99%.This process is simple, warm and economical.
作者
尚宇
黄艳
张淳
郭亚飞
李飞
SHANG Yu;HUANG Yan;ZHANG Chun;GUO Ya-fei;LI Fei(Shaanxi Environmental Monitoring Center,Xi’an 710054,China)
出处
《精细化工中间体》
CAS
2020年第6期25-28,共4页
Fine Chemical Intermediates
