Synthesis of New Aroma Chemicals Using Prenyl Chloride

Abstract

In order to find new aroma chemicals, various type of terpenoid compounds are prepared using prenyl chloride (1) as a raw material. The main reaction is the condensation of (1) and aldehydes with aqueous sodium hydroxide (ca. 50%) in the presence of a tetrabutylammonium iodide catalyst. The prenylated aldehydes (2) are converted to the corresponding alcohols (3), acetals (4) or nitriles (5). Alcohols (6) are also obtained from (2) and various allylic Grignard reagents. Those compounds are evaluated by their odor : 2, 5-Dimethyl-2-propyl-4-hexen-1-ol (3c), 2, 5-dimethy;-2-phenyl-4-hexenal (2 e), 2, 5-dimethyl-2- (p-methylphenyl) -4-hexenal (2 h), 2, 5-dimethyl-2-propyl-4-hexenal dimethyl acetal (4 c) each emited an odor that will qualify them for cosmetic application.