Chemical News

Tuesday, March 10, 2009

Flavoring Compound Synthesis by Enzymatic Esterification

cis-Pellitorin (1) is isolated from the tarragon plant. It used as a pungent flavoring to give a “hot” taste to foods and oral hygiene products. I.-L. Gatfield and co-inventors describe a method of preparing synthetic 1 by the reaction of ester 2 and i-BuNH2 in the presence of an enzyme catalyst.

The crude product is purified by silica gel chromatography and isolated in ~80% yield with a GC purity of 99.4%. The patent claims do not mention a specific enzyme catalyst, but specify that it must have lipase activity and is on a support. The enzyme used in the examples is Chirazyme L-2 from Roche.

The examples indicate that the reaction can be carried out without solvent or in toluene. The concentration of the enzyme is ~40 wt% of the amount of ester 2. Much of the discussion in the patent relates to plants or molecules with similar pungent taste properties. There are also details on the preparation and the testing of flavors for chewing gum, mouthwash, and toothpaste using 1. 1H and 13C NMR data for 1 are given. The patent does not provide a preferred method for isolating and purifying 1 on a commercial scale, although one example mentions molecular distillation

Source: CAS & Patent Watch