Лако-красочные материалы — производство

The Carroll, or an equivalent, reaction between linalool and an acetoacetic ester gives geranylacetone. Further elaboration, as shown in Scheme 4.28, produces sesquiterpenes such as nerolidol, farnesol and bisabolol which have some perfumery use, although their odours are weak. Bisabolol is used mostly because of its anti-inflammatory and

anti-bacterial properties. The main use for these materials is as inter­mediates for vitamins E and K.

The sesquiterpenes important in odour terms mostly have complex cyclic structures. The problem of elimination of alcohols to produce olefins on attempted isolation is even more acute with sesquiterpenes than with monoterpenes because of their higher boiling points, which require more vigorous distillation conditions. The sesquiterpenes responsible for the odours of vetiver and patchouli oils have complex structures (21-24), which can only be reached by lengthy and hence uneconomic syntheses. As their names suggest, the vetivones occur in vetiver oil and the patchoulane derivatives in patchouli.

Caryophyllene is the main hydrocarbon component of clove oil, from which it is produced as a by-product of eugenol extraction. The endocyclic double bond of caryophyllene is highly strained and reacts readily with a variety of reagents. Usually both double bonds become involved in a traws-annular reaction, followed by rearrangements to give mixtures of polycyclic products. Some of these mixtures find use as woody ingredients in perfumes. Caryophyllene and two typical reaction products from it are shown in Scheme 4.29.

Longifolene is present in Indian turpentine, which is obtained from the species Pinus longifolia. This hydrocarbon also has a strained skeleton and treatment with acid causes rearrangement to isolongifo- lene. Treatment of this with a peracid under acidic catalysis gives

isolongifolanone, which has a rich woody-amber odour. Isolongifolene can also be hydroformylated to give materials such as Amboryl Acetate®, which also has a woody-amber character. These reactions are shown in Scheme 4.30.