3.1.9. General Procedure for the Synthesis of Compounds **15** and **16**

The general procedure is illustrated below with compound **15** as a specific example. To a solution of curcumin bisacetate **17** (0.76 g, 1.68 mmol) in DMF (8 mL) was added K2CO3 (0.58 g, 4.20 mmol) and propyl bromide (0.435 g, 3.53 mmol) sequentially at 0 ◦C. The reaction mixture was stirred at room temeperatre for 20 h and then H2O (10 mL) and diluted HCl(aq) (1 *N*, 5 mL) were added to quench the reaction. The aqueous layer was separated and extracted with EtOAc (3 × 10 mL). The combined organic layer was dried over MgSO4, filtered and concentrated to give the crude product, which was subjected without any purification to the base-promoted hydrolysis reaction [NaOMe (0.190 g, 3.53 mmol), MeOH (5 mL)]. The reaction was followed by TLC until no starting material was present. The resulting mixture was then concentrated to give the crude product, which was then purified by flash chromatography on silica gel with EtOAc/*n*-hexane/CH2Cl2 (1:2:1) to afford compound **15** (0.213 g, 28% yield for two steps) as a yellow solid.
