3,4,5-Trimethoxybenzaldehyde → Trimethoxybenzylidene pentanedione

Reaction equation

[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:8]=[C:9]([O:13][CH3:14])[C:10]=1[O:11][CH3:12])[CH:6]=O.[C:15]([CH2:18][C:19](=[O:21])[CH3:20])(=[O:17])[CH3:16].N1CCCCC1>C1CCCCC1>[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:8]=[C:9]([O:13][CH3:14])[C:10]=1[O:11][CH3:12])[CH:6]=[C:18]([C:19](=[O:21])[CH3:20])[C:15](=[O:17])[CH3:16]

Participants

Procedure

3-(3,4,5-trimethoxybenzylidene)-2,4-pentanedione (hereinafter “HSS”) was prepared by the condensation of 3,4,5-trimethoxy benzaldehyde with acetyl acetone in the presence of piperidine and cyclohexane as the reaction medium at reflux temperature under continuous azeotropic water removal. The reaction takes about eight hours to complete. The reaction product was purified by crystallization with methanol. The typical yield of HSS is about 68% with a purity, as determined by GC, of 99.1%. HSS is an off-white free-flowing powder with a melting point of 83-86° C. with a λmax at 319 nm.