Die Strukturen der essentiellen ungesättigten Fettsäuren, Kristallstruktur der Linolsäure sowie Hinweise auf die Kristallstrukturen der α-Linolensäure und der Arachidonsäure / The Structures of the Essential Unsaturated Fatty Acids. Crystal Structure of Linoleic Acid and Evidence for the Crystal Structures of α-Linolenic Acid and Arachidonic Acid

Abstract

Abstract The essential fatty acids linoleic, α-linolenic and arachidonic acid have been crystallized for the first time. The crystal and molecular structures have been elucidated by X-ray analysis. Linoleic acid crystallizes monoclinic P21/c with a = 4298(3), b = 463.2(3), c = 937.7(6) pm, β = 109.38(8)°, Z = 4. The closely packed molecules are stretched with a tttttts̄CssCs̄tt conformationa. By comparison of the unit-cell constants and calculated densities of the unsaturated fatty acids it may be shown that both α-linolenic acid and arachidonic acid also possess stretched structures in the crystal lattice, α-linolenic acid must display a tttttts̄CssCs̄s̄Cs and arachidonic acid a tts̄CssCs̄s̄CssCs̄ttt conformation.