Vemolic acid

One species of Euphorbia in Brazil (Bernardia pulchelld) has been determined to contain more than 90% vemolic acid in the triglyceride [120]. This level of single-component purity is equivalent to the level of ricinoleic acid typically found in castor oil. These different varieties of epoxidized oil plants will probably continue to be the subject of agricultural development in the coming years. 

A number of naturally-occurring fatty acid epoxides have been isolated from various sources. Among these are cw-O.lO-epoxyoctede-ranoie acid,17 cw-9,10-opoxyoctadec-li-enoic (coronaric) acid,laM cis-12,13-epoxy oetadec-8-enoio (vemolic) acid,10 - 77 and cie-16,16-i- poxyoctadeca9,12-dienoic acid 878... 

Epoxidised oils (with isolated double bonds), such as epoxidised soybean are used as plasticisers. The natural occurrence of epoxidised fatty acids could be exploited to reduce processing costs on the pathway to polymerisation. For example, seed oils derived from Vernonia galamensis and Euphorbia lagascae both contain significant proportions (60-80%) of the epoxy acid vemolic acid, with interesting applications in greases and polyurethane applications (Turley et al., 2000). 

These are average values from recent years crops bContains 89.2% ricinoleic and 1.4% dihydroxystearic acids Contains 59.8% crepenynic acid "Contains 78.0% licanic acid and 4.0% hydroxy acids eHigh-erucic-acid variety Contains 71.3% vemolic acid 6Contains 78.5% vemolic acid and 5.8% hydroxy fatty acids. 

Vemolic acid (or c -12,13-epoxy-octadec-cA-9-enoic acid) (Fig. 6) was the hrst naturally occurring epoxy fatty acid isolated from the seed oil of Vernonia anthelmintica. It is also found in several Compositae, Malvaceae, and Euphorbiaceae species in signihcant amounts. Other epoxy acids include... 

Some contain vemolic acid (12,13-epoxyoleic acid). This has several potentially useful properties, and attempts are being made to produce an economically viable crop. 

Oils containing epoxy acids Several natural epoxy acids are known, but vernolic acid (12,13-epoxyoleic) is the most common and occurs at high levels in several seed oils. Of these, serious attempts are now being made to develop Vernonia galamensis (73-78% vemolic acid) and Euphorbia lagascae (57-62% vernolic acid) as commercial crops (198). Several potential uses of this acid and the seed oils in which it occurs are being explored. 

Pascual, M.J., and E. Correal. 1992. Mntation studies of an oilseed spurge rich in vemolic acid. Crop Sci. 32 95-98. 

Typically, this oil was rich in erucic acid, which is still available from high-erucic rapeseed oil (HEAR) or from crambe oil. Erucic acid is mildly toxic to humans in large doses but is used as a food additive in smaller doses. The variety low in erucic acid (<5% or <2%) and also in glu-cosinolates (LEAR, double zero) is now more important. The oil typically contains palmitic (4%), stearic (2%), oleic (56%), linoleic (26%), and linolenic acids (10%). Rapeseed lends itself to genetic manipulation and rapeseed oil containing a lower level of linolenic acid or higher levels of lauric, stearic, or oleic acid or new acids, such as 8-linolenic, ricinoleic, or vemolic acids, are being developed for commercial exploitation. ... 

Aminododecanoic acid was obtained by hydrogenation of vemolic acid, 12,13-epoxy-18 l(9Z), to give 12,13-epoxystearic acid. The latter compound was oxidized by HIO4 to yield 12-oxododecanoic acid, which was treated with hydroxylamine to form the oxime. The oxime was then catalytically reduced to yield the requisite 12-aminododecanoic acid. 11-Aminoundecanoic acid was prepared from the 12-oxodo-... 

Another interesting oilseed crop tiiat has been researched in our laboratories for several years is Euphorbia lagascae (22) (Fig. 3). This oilseed crop contains vemolic acid (12,13 -epoxy-cis-9-octadecenoic acid), with a natural epoxide content of 65% (see Table 2). 

For the synthesis of methyl 9,10 12,13-diepoxystearate (27,30), Euphorbia la-gascae, which is rich in vemolic acid, was used as the raw material. Following a one-step transesterification with MeOH/NaOH, pure methyl vemolate was obtained in high chemical yields by vacuum distillation. Methyl 9,10 12,13-diepoxystearate... 

Dihydroxyoleic acid (30) (Fig. 2.15) is formed from vemolic acid (39) (which, in turn, is formed from linoleic acid) in crushed seeds of Xeranthemum annuum (As-teraceae) and Euphorbia lagascae (Euphorbiaceae). 

Epoxy fatty acids also are found as components of triglycerides of the seed oils (Smith, 1970). This unusual fatty acid type is sporadically distributed in species of several taxo-nomically unrelated plant families. Z-12,13-Epoxyoleic acid (vemolic acid) (39) (Fig. 2.15) is biosynthesized from linoleic acid in the seeds of Xemnthemum anmum and Euphorbia lagascae (Hitchcock and Nichols, 1971). This compound and Z-9,10-epoxy stearate are synthesized by the introduction of oxygen from O2 across the double bonds of linoleic and oleic acids, respectively (Butt and Lamb, 1981 Morris, 1970). The biosynthesis of epoxy fatty acids is related to that of dihydroxy fatty acids, and epoxy fatty acids may serve as precursors for the latter type of compound. 

Further studies on this topic required the preparation of the four geometrically isomers of methyl 12,15-octadecadienoates-9,10-J2- [50, 51] They were prepared by Wittig reaction between cis- or trans-3-hexenyl-triphenylphosphonium bromide and methyl 12-oxododecanoate-9,10-c/2 prepared from vemolic acid as above described. 

P450 BM3 and its variant F87V were exploited for the preparation of (+)-leukotoxin B [(+)-12(5),13(7 )-vemolic acid] from linoleic acid as well as 14(5),15(f )-epoxyeicosatrienoic acid from arachidonic acid, with application of G-6P-DH as the cofactor-regenerating enzyme (Fig. 8.11) [261]. 

Falck JR, Reddy YK, Haines DC, Reddy KM, Krishna UM, Graham S, Murry B, Peterson JA (2001) Practical, enantiospecific synthesis of 14,15-EET and leukotoxin B (vemolic acid). Tetrahedron Lett 42 4131 133... 

Stearic acid (18 0) Vemolic acid (18 1) a-Elaeostearic acid (18 3)... 

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