Isovanillin → 5-Hydroxy-1-indanone

Beteiligte Stoffe

Reaktionsschritte

The indanone building blocks (18) were prepared as described in Scheme 11. The commercially available vanillin (33a) was reacted with Wittig reagent (34) in toluene at reflux temperature to give the corresponding unsaturated ester (35a) as cis and trans mixture. The ester (35a) was subjected to hydrogenation using palladium-carbon catalyst in methanol to give the saturated ester (36a). The ester (36a) was hydrolyzed using aqueous potassium hydroxide in THF to give carboxylic acid which after cyclization in the presence of concentrated sulfuric acid gave the target 6-hydroxyindan-1-one (18a) in overall good yield. Similarly, 5-hydroxyindan-1-one (18b) was prepared from the commercially available starting building block isovanilin (33b) in overall good yields.

Herkunft & Nachweise