Agathic acid

Agathic acid Agatholic acid Communic acid... 

Copals, sometimes referred to as immature amber, originate from Africa, Asia or central American countries and derive from the Araucariaceae and Leguminosae families. Polymerised communic acid and agathic acid are found as the main compounds in these fossil resins. The extreme hardness of copal results from polymers of resin acids such as ozoic acid, an enantiomer of communic acid that can polymerize and thus enable fossilization [86]. They are still commonly used today for varnishing and protecting wood. 

Imbricataloic acid has been obtained19 together with agathic acid 19-monomethyl ester from Pinus massoniana needles. The labdane acid, anticopalic acid, has been... 

The structure of the epoxy-dialdehyde (15), from Afromomum daniellii (Zingiberaceae), was established by correlation with c -12-norambreinolide. The hydroxy-acid (16), salvic acid from Eupatorium salvia,and the ring B seco-labdane jhanic acid (17) from Eupatorium jhanii are two further diterpenoids from these species of the Compositae. The structure of the latter rests on interpretation of the H and C n.m.r. data. Gutierrezia lucida (Compositae) contains the 13-epimeric acids (18) related to agathic acid together with the butenolide (19). Some esters of 6-hydroxylabdane-17-carboxylic acids were detected in G. mandonii. The investigation of Cistus species has continued. The ent-labdane acetyl-laurifolic acid (20) is a component of Cistus laurifolius ... 

The cyclization of agathic acid by formic acid to afford the tricyclic isoagathic acid has been known for many years. The stereochemistry of the comparable cyclization products (15) and (16) of methyl jE-anticopalate (13) and methyl Z-anticopalate (14)... 

Compositae). The tetracyclic beyer-15-en-19-oic acid with the normal configuration was also present. The phenol sugiol and a number of bicyclic relatives of agathic acid have been obtained from Araucaria angustifolia. 

The dehydrogenation of agathic acid by selenium has been studied under various conditions. The results have been rationalized in terms of the formation, on the one hand, of tricyclic compounds such as 1,6-dimethylphenanthrene and, on the other hand, of bicyclic compounds such as 1,2,5-trimethylnaphthalene. 

The fruit oil of the leguminous tree Pterodon pubescens contains geranylgeraniol (3) and its terminal epoxide (98). This terminal epoxide is highly lethal to the cercariae of Schistosoma mansoni, the causative agent of schistosomiasis (Gilbert, 1977). Other unsaturated diterpenes such as dehy-droabietic acid, agathic acid, and copalic acid prevent cercar-ial penetration. 

Agathic acid, a well-known labdane diterpene, was identified in a species of the genus Chromocleista from sediment collected at a depth of 70 m in the Gulf of Mexico (Park et al, 2006). 

The new diterpene, named isoagatholactone, proved to be the first naturally occurring compound with the carbon skeleton of isoagathic acid, the acid-catalyzed cyclization product of agathic acid (30, 159). Structure (63) for isoagatholactone without sterical implications was suggested... 

In Pinaceae resins, for instance, fully trimethylsilylated derivatives of 7-hydroxy-DHA, 15-hydroxy-DHA and 15-hydroxy-7-oxo-DHA have been identified, as well as all the other abietadiene and pimaranediene acids present in these resins. The derivatization was ineffective on some labdane alcohols such as larixyl acetate, a marker compound for Venice turpentine, but in general labdane compounds have been identified in their trimethylsilylated form. Labdane acids, such as communic, agathic, agathalic, agatholic and acetoxy agatholic acids, that are among the most important constituents of sandarac... 

A number of partial syntheses have been described in the bicyclic series. The synthesis of methyl (12S)- and (12i )-hydroxylabda-8(17)-en-19-oate utilized the aldehyde (10) as an intermediate. This was obtained from podocarpic acid. The synthesis of the furan methyl lambertianate (11) from dimethyl agathate has been described. Examination of the n.m.r. spectra of the levantenolides (12) has led to a revision of their C-12 stereochemistry. a-Levantenolide has the (12i ) configuration whereas jS-levantenolide has the (125) configuration. The functionalization at C-12 of labdanes by oxidation of C-15 alcohols with iodine and lead tetra-acetate has been described. ... 

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