Dodecenoic acid

Dodecenoic acid, 37, 31 DodECYLAMINE, N methyl, 36, 48 n Dodecyl fluoride, 36, 42 Doebner reaction, 31, 35... 

Fatty acids are also characteristic natural products of species of thrips in a diversity of genera. A total extract of Hoplothrips japonicus was dominated by (E)-3-dodecenoic acid which is considered to be an alarm-aggregation pheromone (Z)-5-dodecenoic acid is a minor concomitant ( ) 2-Methylbutyric acid, a defensive allomone of swallowtail larvae ( ), is the only free fatty acid detected in the previously described anal exudate of Varshneyia pasanii (20). It is believed that the anal discharge of this species, thoroughly dominated by alkanes, acetates, and oxygenated monoterpenes, exhibits an increased repellent punch because of the presence of the C5 acid. 

The telomer of nitroethane, 134, was used for the synthesis of 11-hydroxy-8-frans-dodecenoic acid (135) (125). Apparently, the internal double bond of 134 must have a trans configuration from a mechanistic consideration. The nitro group was converted to alcohol via ketone, and the two-carbon homologation was carried out from the terminal double bond. This acid is converted to recifeiolide (136), a naturally occurring macrolide. 

Cross-metathesis of methyl oleate with 3-hexene under similar conditions led, in addition to the above products [Eq. (54)], to 3-dodecene and the methyl ester of 9-dodecenoic acid. 

This distillation is of importance if omitted, the final 2-dodecenoic acid is difficult to purify. 

The mixture of dodecenoic acids exhibited Amax at 210 m/z ( 11,980) in hexane. From the extinction coefficient (13,650) for the pure 2-isomer and that (about 1000) for the 3-isomer, it is calculated that this mixture contains about 13% of the latter. A small amount of dodeca-noic acid also appears to be present. 

The short chain fatty acids (C to. ) detected in plain cashews could be detected in roasted samples also, in higher amounts. Dodecenoic acid was the only unsaturated fatty acid among them. These fatty acids are formed by the degradation of glycerides by mild enzymatic action or hydrolysis. 

An unusual 9-10 desaturase is present in the codling moth, Cydia pomunella. It forms (25)—9-dodecenoic acid, which then... 

The carbon-carbon double bond is not isomerized to a detectable extent during saponification of the ester or distillation of the acid thus the 2-methyl-2-dodecenoic acid will have the same isomeric composition as the sample of ester from which it was obtained, and it consists entirely of a,/3-unsaturated isomers. 

Methyl-2-dodecenoic acid has been prepared by bromination of methyl 2-methyldodecanoate with N-bromosuccinimide, followed by dehydrobromination with quinoline and saponification of the ester.6 The present procedure is an adaptation of the method of Cason, Allinger, and Williams.6... 

Higher temperatures at this point tend to promote dehydro-bromination under the acidic conditions with the formation of 2-methyl-2-dodecenoic acid. 

If the distillation is carried out in a Claisen flask, the final product is impure, apparently contaminated with about 10% of 2-methyl-2-dodecenoic acid. 

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