Cardanol isolation

Besides typical cardanol-like structure, Sleeper and Fenical have identified in 1977 navenone, an alkylphenol derivative as a component of trail pheromone of the mollusk Navanax inermis [27]. Another alkylpheno lie derivative, plakinidone, has beed isolated in 1991 from a Caribbean sponge Plakortis angulospiculatus [26]. In 1995 the carboxylic acid derivative of alkylphenol - elenic acid was isolated from the Indonesian sponge Plakinastrella [25]. The structures and formulas of known monohydric phenolic lipids are presented in Fig. (1). 

Apart from cardanol (Fig. 1-1,2,4, and 5) which collectively is a minor natural component in Anacardium occidentale, the first 3-substituted monohydric phenols isolated were, ginkgol (identical with cardanol monene), (depicted in Fig. 1-2), from Ginkgo biloba, and camnospermanol, (Fig. 1-6), from Camnospermum auriculata. More recently a number of 4-substituted monohydric phenols, (depicted in Fig.l), have been obtained from natural sources including, elenic acid, R-2,4-dimethyl-22-(4-hydroxyphenyl)-docos-3(E)-enoic acid, 7, navenone,... 

The skin irritancy of cardanol monoene isolated from the fruits of the spice pink pepper, Schinus terebinthifolius, has been examined. However, it was supposed that the irritative effect, which was manifested after a long latency period, was also contributed to by ingredients of the essential oil, for example, by phellandrene and delta-3 carene [255]. Accordingly, it was indicated that experimental tests with animals were necessary before the spice can be forbidden for sale . 

Pentadecenyl)phenol, common name cardanol, is isolated from Ginkgo bilobaOil [21]. Phenol and 3-(8 -pentadecenyl)phenol react with methanal in presence of a strong acid catalyst such as concentrated sulfuric acid or in a basic environment according to the simplified equation 50. Some of the reactions of this alkyl phenol have already been illustrated in Scheme 12. 

In the determination of carbamate insecticide residues, the parent phenols were coupled with diazotized p-nitroaniline and the azo dye isolated (29). In a combined TLCVGLC procedure for quantitative determination of the polyunsaturated constituents of the cashew phenols following an initial TLC separation, the eluted phenols, cardanol, 2-methylcardol, and a small proportion of anacardic acid each containing mono-, di-, and triene constituents were examined by GLC (30). 

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