Abietinic acid

Tall oil fatty acids consist of resin acids (25% to 30%) and of a mixture of linolic acid, conjugated Cig fatty acids (45% to 65%), oleic acid (25% to 45%), 5,9,12-octadecatrienic acid (5% to 12%), and saturated fatty acids (1% to 3%). Resin acids are abietinic acid, dehydroabietic acid, and others. Properties of fatty acids are shown in Table 6-1. 

Abietic acid sylvic acid, abietinic acid C20H30O2 302.45 If. 182 i. V. s. V. S. 

CAS 514-10-3 EINECS/ELINCS 208-178-3 Synonyms Abietinic acid 13-lsopropylpodocarpa-7,13-dien-15-oic acid Sylvie acid... 

Abietic acid methyl ester. See Methyl abietate Abietinic acid. See Abietic acid... 

Retene is a methyl isopropyl phenanthrene (Fig. 2). As mentioned above, Wakeham [43] was the first to address the natural non-combustion production of retene in relation to lake sediments. The starting material for retene is abietic acid, a diterpenoid found primarily in the resin of coniferous trees. When burned, the abietic acid forms retene. It can also degrade via one of two pathways to retene without combustion (Fig. 5). One pathway is through dehydro abietin and another intermediate to retene. The other proceeds through dehydroabietane, another intermediate to simonellite and finally to retene. These mechanisms can occur in both the atmosphere [44] and in aquatic systems. Therefore, where there is abietic acid, retene can follow. This becomes especially important in areas where there are high densities of conifers, and thus abietic acid. 

The Labdane Series.—The conifers are an important source of diterpenoids. Araucaria excelsa has been examined and manool, torulosol, abietinol, torulosal, and abietinal have been detected in the neutral fraction of the oleoresin. This fraction also contained the epimeric 18- and 19-nor-labdane-4,13-diols (1), which may arise by autoxidation of torulosal. Chromatography of this aldehyde on alumina or silica led to up to 14% of the epimeric C-4 hydroperoxides. Consequently, whenever these nor-diterpenoids are detected, the possibility that they are artefacts has to be borne in mind. Oxidative decarboxylation of acetylcupres-sic acid by lead tetra-acetate affords a synthetic entry to this series of compounds. 

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