Acetic Acid → 1-(4-Carboxyphenyl)-4-(4-dimethylaminocinnamylidene)-3-methyl-2-pyrazolin-5-one

Participants

Reaction Steps

1-(4-Carboxyphenyl)-3-methyl-2-pyrazolin-5-one (2.18 g, 0.010 mol), 4-dimethylamino-cinnamaldehyde (1.75 g, 0.010 mol) and glacial acetic acid (10 ml) were mixed together to form a slurry. It was heated to reflux with stirring, held at reflux for five minutes and then cooled to room temperature. EtOH (20 ml) was added to the reaction mixture, which was heated again to reflux, held there for five minutes, and cooled to room temperature. The product was isolated by filtration, washed in succession with ethanol and ligroin, and dried. The reaction was repeated twice on the same scale and the products obtained were all combined. They were treated further by first slurrying in refluxing EtOH (150 ml), isolating the solid by filtration while hot, and then slurrying in refluxing MeOH (200 ml) and isolating it again, while hot, by filtration. The mp was 282°-284° C. The NMR and IR spectra were consistent for the structure assigned. The C, H, and N elemental analyses were in agreement with those calculated for the empirical formula of the dye.

Provenance & Evidence