Figure 1. Chemical structure of AEL (alkyl-ether-lipid) subtypes: DAGE, AAGPL and the structure of the common fragment 1-O-alkyl-glyceryl ether lipid (AGEL). For simplification purposes, chirality is not depicted. Figure 1. Chemical structure of AEL (alkyl-ether-lipid) subtypes: DAGE, AAGPL and the structure of Figure 2. Synthesis of alkyl-glycerolipids 4a—-i and derivatization as diacetyl esters 5a-i. (i) TsCl, Pyridine, 1 h, 0 °C then 24 h, rt; (ii) preparation of the alcoholate: NaH, ROH, dimethoxyethane, 1 h, then addition of 2, 100 °C then 48 h, reflux; (iii) HCl 2N, Ethanol, 4h, reflux. Method A (iv): acetic anhydride, pyridine, 60 °C, 30 min. and then 1 night at 20 °C; Method B (v): acetyl chloride, 5 min. 140 °C. Figure 3. Chromatogram of alkyl-glycerols diacetate from chimera (Chimaera monstrosa) liver oil. Figure 4. Comparative analysis of alkyl-glycerols of chimera (Chimaera monstrosa) and shark liver (a mixture of two species: Centrophorus squamosus and Somniosus microcephalus). Bars represent mean value and error bars represent SD, n = 6. Neither C19:0 nor C22:0 alkyl chains were detected. ‘igure 4. Comparative analysis of alkyl-glycerols of chimera (Chimaera monstrosa) and shark liver (a After derivatization as acetate, we optimized the temperature program for the separation and identification of alkyl-glycerolipids by GC-MS (see Supplementary Materials SI2.1, SI2.2). This method confirmed the results obtained using GC-FID. Table 2. Statistical data for analytical procedure for GC. 4. Conclusions
