4 allylanisole

AITC, capsaicin, ruthenium red (RR), HC-030031, capsazepine (CPZ), acacetin, 4-allylanisole, p-anisaldehyde, apigenin 7-glucoside, L-carveol, β-caryophyllene, trans-p-methoxycinnamaldehyde, methyl eugenol, rosmarinic acid, and dimethyl sulfoxide (DMSO) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Pachypodol was obtained from Chem Faces (Hubei, China). The media used for cell culture were obtained from Life Technologies, Inc. (Grand Island, NY, USA). The structures of AITC, acacetin, 4-allylanisole, p-anisaldehyde, apigenin 7-glucoside, L-carveol, β-caryophyllene, trans-p-methoxycinnamaldehyde, methyl eugenol, pachypodol, and rosmarinic acid were shown in Fig 1.

To synthesize MMPP, 4-Iodo-2-methoxyphenol (500 mg, 2 mmol, Sigma Aldrich, St. Louis, MO, USA) and 4-allylanisole (296.4 mg, 2 mmol, Sigma Aldrich) were added to triphenylphosphine (105 mg, 0.4 mmol), Pd(OAc)₂ (44.9 mg, 0.2 mmol), and tributylamine (451 μL, 1.9 mmol) in a 25 mL round bottom flask. The reaction mixture was stirred for 2 h at 45 °C in an argon atmosphere. The product was purified by flash silica gel chromatography using hexane and ethyl acetate (3:1 mixture v/v) as the mobile phase. Reduction of the alkene or aldehyde of α, β-unsaturated aldehyde moieties resulted in stable compounds to protect the phenolic alcohol from ether. The purity of MMPP was over 99.5%, as determined with HPLC analysis.