GTRS and 2D-NMR studies of alpha and gamma linolenic acids each containing the same H2C14-(H–C[dbnd]C–H)–C11H2–(H–C[dbnd]C–H)–C8H2 moiety

Abstract

• C14H2 -(H–C13 = C12–H)– C11H2 -(H–C10 = C9–H)– C8H2 is exactly the same structure in both Linolenic Acid isomers. • In γ-LN, chemical shifts for sites C14H2 and C8H2 are the same (1H = 2.65 ppm; 13C = 24.9 ppm). • In α-LN, 1H chemical shifts for sites C14H2 and C8H2 are the same (2.65 ppm) whereas the 13C chemical shifts are discretely different (24.9 ppm versus 24.7 ppm). • Chemical shifts for C11H2 are similar and unequal (1H = 0.78 ppm, 13C = 13.3 ppm α-LN; 1H = 0.72 ppm 13C = 13.5 ppm γ-LN). • Chemical shifts for C2H2 are similar and unequal (1H = 2.12 ppm, 13C = 33.4 ppm α-LN; 1H = 2.11 ppm 13C = 33.2 ppm γ-LN). • Moiety C17H2-(H–C16 = C15–H) is molecular site among redundant structures in α-LN at which spectroscopic differences are the most different and most important.