Salicylaldehyde → p-Toluenesulfonate

Participants

Reaction Steps

A solution of 2-hydroxy-benzaldehyde (1.5 g, 12.16 mmol), potassium carbonate (8.4 g, 60.8 mmol) and toluene-4-sulfonic acid 3-methoxy-propyl ester (14.85 g, 60.8 mmol) in DMF (30 mL) is stirred at 50° C. for 3 h. The solvent is concentrated under reduced pressure, H2O is added, and the aqueous layer extracted twice with ethyl acetate. The combined organic extracts are dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue is purified by flash column chromatography on silica gel (hexane/EtOAc 4/1 to 1/2) to afford the title compound together with 50% of remaining tosylate: MS 195.0 [M+H]. Rt (HPLC, Nucleosil C18, 10:90-100:0 CH3CN/H2O+0.1% TFA within 5 min, then 100% CH3CN+0.1% TFA): 5.08 min. The mixture is further used as is in the next step.

Provenance & Evidence