GC‐MS characterization (Chemical lonization and electron impact modes) of the methyl esters and oxazoline derivatives of cyclopropenoid fatty acids

Abstract

The CI‐(CH4) mass spectra of the methyl esters and the EI mass spectra of the oxazoline derivatives of three cyclopropenoid fatty acids (malvalic, sterculic and α‐ hydroxy‐sterculic acid) from the seed oil ofPachira aquatica were found to be useful for structure elucidation of such compounds. Furthermore, some hitherto unknown minor fatty acids were identified and the nuclear magnetic resonance data of the oil and α‐hydroxysterculic acid methyl ester are presented.

Screening analysis of unknown seed oils

“…BPX-70 TM ∆5-unsaturated polymethylene-interrupted fatty acids in Ranunculaceae [120]; γ-linolenic, α-linolenic, and stearidonic acid in Boraginaceae [121]; acetylenic fatty acids in Olacaceae [11] Carbowax 20M TM /DB Wax TM Conjugated triene fatty acids in Cucurbitaceae [90], positional monoene isomers in Sapindaceae [2,122], ∆5-unsaturated polymethylene-interrupted fatty acids in Cupressaceae, Pinaceae, and Taxaceae [123] CP-SIL-88 TM Unusual unsaturated double bond and configuration isomers in Ranunculaceae [124] and Pinaceae [125] CP-WAX 52CB TM Methyl-branched and ∆5-unsaturated polymethylene-interrupted fatty acids in Ginkgo biloba [20] DB-23 TM Cyclopropanoic, cyclopropenoic, and hydroxy fatty acids in Bombacaceae [14], positional monoene isomers in Sapindaceae [2,122], conjugated triene, tetraene, and keto fatty acids in Chrysobalanaceae [21,77,126] and Euphorbiaceae [6], acetylenic acids in Olacaceae [3,128] and Santalaceae [3,128] SILAR 5 CP TM ∆5-unsaturated polymethylene-interrupted fatty acids in Ranunculaceae [129], allenic fatty acids [13] SP2330 TM Polyunsaturated fatty acids in various species [130] Detection of the individual compounds can be made with a flame-ionization detector (FID).…”

“…As only a relatively small number of signals (> 9) can be observed, the information impact of 1 H NMR spectra is limited in comparison with that of 13 C NMR spectra (see 4.2.2). Nevertheless, the detection of a number of functional groups in seed oils, such as allenes [15,69], conjugated double bonds [8,15,70,71], conjugated double-triple bonds [3,10,11,72], cyclopropane [73] and cyclopropene rings [74], cyclopentene [75], epoxy [5], hydroxy [14,76], and terminal vinyl groups [3] is possible by their characteristic 1 H NMR signals. The methylene groups adjacent to a keto group show similar shift values as those adjacent to the carboxyl group when located remote from the carboxyl or other functional groups.…”

“…for acetylenes [84][85][86][87], allenes [15,69], conjugated acetylenes [10], conjugated dienes [5,85,88], trienes [89][90][91][92], tetraenes [8,91,93], conjugated olefin-acetylenes [3,11,72], cyclopropenes [14,83], epoxy [94], hydroxy [14,95,96], keto [95,97], and olefins (monoenes [84,85,87,98]; polyenes, methyleneinterrupted [99][100][101][102]; non-methylene-interrupted [98,103,104]). …”

Identification of Cyclopropyl Fatty Acids in Walnut (Juglans Regia L.) Oil

“…45,46 . Previously, dihydrosterculic acid (4) as well as sterculic acid (5) were found in Pachira aquatica seed oils 47 . The biosynthesis of cyclopropane and cyclopropene fatty acids has been discussed in some reviews 48,49 .…”

Pachira glabra Pasq. Essential Oil: Chemical Constituents, Antimicrobial and Insecticidal Activities

“…Fatty acids such as malvalic acid, sterculic acid and α-hydroxy-sterculic acid and palmitic acid were previously described from the plant 5,6 . The phytochemical analysis of P. aquatic described the isolation of an antifungal fungitoxin known as isohemigossypolone 7 In Nigeria, P. glabra is cultivated and grown as an ornamental plant in home yards and gardens for its attractive flowers, and for the seeds, which is eaten as beans.…”