Synthesis of moss fragrance component ethyl divaricatinate

Ethyl 2-hydroxy-4-methoxy-6-propylbenzoate (Ethyl divaricatinate, Compound 4) is a key component in moss fragrance spice extracts from oakmoss and treemoss. Compound 4 was synthesized by four-step reactions (addition and condensation reaction, aromatization reaction, catalytic hydrogenation reaction and methylating reaction) using hept-3-en-2-one and diethyl malonate as initial materials. The results showed that:1) The reaction route had the advantages of available initial materials, moderate temperature, high yield and easy isolation of intermediates and target product, and the total yield reached 53%. 2) In order to prevent side reactions in the synthesis process of Compound 4, methane iodide was added drop by drop with the optimum mole ratio of 1:1 for methane iodide to ethyl 2, 4-dihydroxy-6-propylbenzoate (Compound 3).