Thionyl Chloride → 4-Acetoxy-3-methoxy-cinnamic acid azide

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Reaction Steps

34.0 g (0.145 mol) of 4-acetoxy-3-methoxy-cinnamic acid are suspended in 150 ml of benzene and 21 ml (0.290 mol) of thionyl chloride are added. The mixture is then heated to the boil, under a reflux condenser, for 30 minutes; thereafter, the solvent and excess thionyl chloride are removed by distillation under reduced pressure. The crude 4-acetoxy-3-methoxy-cinnamic acid chloride which remains is dissolved in 150 ml of absolute 1,2-dimethoxyethane, 28.3 g (0.435 mol) of sodium azide are added and the mixture is subsequently stirred for 48 hours at room temperature. The inorganic salts are then filtered off and the filtrate is concentrated under reduced pressure at 30° C, in the course of which colourless crystals separate out. The crystallisation is completed by adding ether. 4-Acetoxy-3-methoxy-cinnamic acid azide of melting point 93°-95° C (decomposition) is obtained.

Provenance & Evidence