Process for synthesizing 2-allyl-3-methoxybenzaldehyde

Abstract

The invention belongs to the field of synthesis of drug intermediates, and discloses a process for industrially producing 2-allyl-3-methoxybenzaldehyde. The synthesis method comprises the following three steps: 1, alkylation reaction: reacting a raw material 3-hydroxybenzaldehyde with allyl bromide under an alkaline condition to obtain an allyl ether intermediate (3-allyl ether benzaldehyde); and 2, Claisen rearrangement reaction of the allyl ether intermediate: under a brand new flowing chemical reaction device (240 DEG C, 2MPa back pressure), dissolving the raw materials in a solvent, pumping the solvent into a microchannel, carrying out rearrangement reaction, and recrystallizing to remove an isomer, so as to obtain the intermediate 2-allyl-3-hydroxybenzaldehyde. And 3, methylation reaction: enabling the 2-allyl-3-hydroxybenzaldehyde to react with dimethyl sulfate under an alkaline condition, so as to obtain the product 2-allyl-3-methoxybenzaldehyde. The total yield of the three steps is 40%. According to the process, the raw materials are low in price and easy to obtain, the process operation is simple and convenient, and the process is suitable for industrial production of the 2-allyl-3-methoxybenzaldehyde.

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