Method for synthesizing 1-(3-oxabutyl cycloalkyl)-1H-pyrazole-4-boronic acid pinacol ester

The invention relates to a method for synthesizing 1-(3-oxabutyl cycloalkyl)-1H-pyrazole-4-boronic acid pinacol ester, which comprises the following steps: 1, taking 3-iodoxetane and 4-bromo-1H-pyrazole as raw materials, and carrying out N alkylation reaction in the presence of weak base to generate an intermediate 4-bromo-1-(oxetan-3-yl)-1H-pyrazole; and 2, reacting the intermediate with strong base, adding triisopropyl borate, reacting for a period of time at low temperature, adding 2, 3-dimethyl butane-2, 3-diol, fully reacting, quenching the reaction liquid, washing, extracting with ethyl acetate, concentrating, recrystallizing and purifying to obtain the product with qualified purity. The method provided by the invention provides a synthesis process with economical raw materials, high reaction yield and easy post-treatment pilot scale-up, and mainly solves the problems that the existing route is not suitable for pilot scale-up due to uneconomical raw materials, low yield, post-treatment needs column sepa