Analysis of the triglycerides of some vegetable oils

Abstract

The aim of this article is to show students that triglycerides, which are the main constituents of natural lipids, consist of a mixture of different compounds, depending on the total number of fatty acid constituents. The students will perform a GC analysis and HPLC.

Substituent effects on 13C chemical shifts of alkyl‐substituted 4‐oxo‐1,3‐dioxolanes and 5‐oxo‐1,3‐oxathiolanes

“…In spite of a statement to the contrary, [5] we agree with Farines and Soulier [4] that the ring conformation of the 4-oxo-1,3-dioxolanes (1-10) is of the O(1) envelope form like the S(3) envelope form in the case of 5-oxo-1,3-oxathiolanes [14] (Scheme 2).…”

“…Probably, 2 greatly favors the equatorial form (2a) and the 5-methyl derivative (3) slightly the equatorial form (3a), which is supported by similar observations in respect of 5-oxo-1,3-oxathiolanes [14] as well as by the similarity of the α-and γ -substituent effects of these compounds as discussed above. The assumption that 4-oxo-1,3-dioxolane (1) favors the O(1) envelope form and would like to have methyl substituents in equatorial positions [4,19] does not interfere with the values of the shift parameters (Table 2) and with the observation 2b that the cis-2,5-dimethyl-4-oxo-1,3-dioxolane (5) is more stable than the trans epimer (6), which could also be concluded from the peak intensities of the 13 C NMR spectra after equilibration.…”

O,O-Monochelate complexes of silicon and germanium halides: The derivatives of l-mandelic N,N-dimethylamide

“…42-43°C (no solvent), b.p. 5-Phenyl-1,3-dioxalan-4-one [28] (52 g, 0.31 mol) and Me 2 NH (250 g of 30 mass % aqueous solution, 1.5 mol) were mixed together and kept in a sealed bottle for 2 days. The precipitate formed was filtered, washed thoroughly with cold water (5 Â 30 ml), and dried in vacuo to afford 33.6 g (0.19 mol, 60.5%) of DL-mandelic N,N-dimethylamide.…”

Optisch aktive Alkohole aus 1,3‐Dioxan‐4‐onen: eine praktikable Variante der enantioselektiven Synthese unter nucleophiler Substitution an Acetal‐Zentren

“…26--1,48 ( m , 5 CH,);l,33 (d,4,01 (ddq,J = 10,68,4,34,6,14,); 5,29 (?,.I = 5.01, H-C (2)). " 97;21,29;22,62: 23,16;29,13;29,31;31,81;34,98: 37,90;70.73;103,SO;167,SS. MS: 130(4), 129(13), 115 (40),87(11), 69 (100).…”

“…Spaltung der so erhaltenen a-Alkoxy-siuren 7 mit Pb(OAc), lieferte die optisch aktiven Alkohole. Da die Ausbeuten fur die Herstellung [31] der Acetale und die Diaste-Schcmri 2 reoselektivitaten der Substitutionen ungenugend sind, scheint dies keine attraktive Variante der nucleophilen Substitution an Acetalzentren zu sein.…”