Fatty acids, part 17. The synthesis and chromatographic and spectroscopic properties of the cyclopropane esters derived from all the methyl octadecenoates (Δ2-Δ17).

✍ Scribed by W.W. Christie; F.D. Gunstone; I.A. Ismail; Mrs.L. Wade

• Publisher: Elsevier Science
• Year: 1968
• Tongue: English
• Weight: 262 KB
• Volume: 2
• Category: Article
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(68)90023-6

✦ Synopsis

All the cis octadecenoic esters have been converted to cyclopropane compounds by reaction with zinc-copper couple and di-iodomethane. Their gas-liquid chromatographic behaviour on four liquid phases is described. Six isomers (2,3-; 3,4-; 4,5-; 15,16-; 16,17 -; and 17,18 -) have distinctive nuclear magnetic resonance spectra and two (2,3 -and 17,18 -) have distinctive infra red spectra.

Discussion

In continuance of our study of series of closely related long-chain acids 1-4) we report the preparation and properties of the methyl esters of sixteen cyclopropane acids. CH2

/\ H [CHzIm.CH--CH.[CH2],,COOCHa re+n--15; n--0--15

Cyclopropane acids are present in a wide range of bacterial a), protozoan6), and plant species v, 8) but only a few compounds have been fully identified because of difficulties of isolation and of structure determination. These include one C17 9), one C~8 (dihydromalvatic), and two C,9 (lactobacillic and dihydrosterculic) acids in addition to acids of higher molecular weight with one or two cyclopropane systemsX°,11). The analysis and identification of these acids has recently attracted interesO 2-14) and we considered it worthwhile to prepare and examine a complete series of cyclopropane compounds.