The HPLC chromatograph of the reaction answer samples with ultraviolet detector. Isoascorbic acid and isoascorbyl palmitate peaks separated well with all the retention occasions of 1.44 and 7.36 min, respectively. The mass spectra of LC-MS indicated that the sample had the mass-to-charge ratios on the molecular ion peak (M -H) of 413.35 and (2M – H) of 827.00, even though D-isoascorbyl palmitate need to have a mass-to-charge ratio of 414 (M), which proved that the synthesized sample is D-isoascorbyl palmitateHOOO OHOH HO OH+HOErythorbic acidPalmitic acidImmobilized lipase NovozymO O O OH O HO H OHErythorbly palmitateFigure 1 The scheme of lipase-catalysed synthesis of D-isoascorbyl palmitate.+H2OSun et al. Chemistry Central Journal 2013, 7:114 http://journal.chemistrycentral/content/7/1/Page 3 ofFigure two HPLC-PDA chromatogram for the elements obtained in the immobilized lipase-catalysed esterification among isoascorbic acid and palmitic acid.Structural characteristic evaluation of the synthesized D-isoascorbyl palmitateThe FT-IR spectrum for the sample isoascorbyl palmitate was presented in Figure 3. The band within the area of 3423 cm-1 is as a consequence of the hydroxyl stretching vibration. The band within the region of 2930 cm-1 and 2850 cm-1 are on account of C-H stretching vibration in CH2 and 1711 cm-1 could be the absorption of C=O stretching vibration. Absorption at 1659 cm-1 was standard for dual bond C = C in isoascorbic acid. The band of 1470 cm-1 was characteristic absorption of CH3. The characteristic absorption at 1341 cm-1, 1225 cm-1, 1151 cm-1, 1110 cm-1 and 1054 cm-1 within the FT-IR spectrum was indicative of C-O-C linkage in the isoascorbyl palmitate whilethe absorption at 721 cm-1 also indicated the presence of linked palmitic acid. 1 H, 13C NMR spectra have been determined as follows (Figure 4), 1H NMR (400 MHz,DMSO-d6): (ppm):11.258 (s,1H,-OH), 8.467 (s,1H,-OH), 5.577(s,1H,-OH), four.739 (d,1H, -CH,J=1.six Hz), four.1-Bromo-3-fluoro-2-methyl-4-nitrobenzene supplier 017(m,3H,-OCH2-OH), 2.2,2′:6′,2”-Terpyridine Purity 279 (t,2H,-CH2CO, J=7.PMID:35901518 6Hz), 1.504 (t,2H,-CH2-,J=6.eight Hz), 1.236 (m,2H,12-CH2-), 0.855 (t,3H,-CH3,J=7.two Hz). 13 C NMR(400MHz,DMSO-d6): (ppm):(173.21 (C1=O), 170.60 (C-1’=O), 152.96 (C-2), 118.74 (C-3), 76.62 (C-4), 68.07(C-5), 63.84(C-6), 34.11 (C-2′), 33.80 (C-3′), 31.7728.94 (C-4′-C12′), 24.95 (C-13′), 24.81 (C-14′), 22.57 (C-15′), 14.39 (C-16′).Figure three FT-IR spectra of isoascorbyl palmitate synthesized by lipase.Sun et al. Chemistry Central Journal 2013, 7:114 http://journal.chemistrycentral/content/7/1/Page 4 ofFigure 4 1H (a) andC NMR (b) spectra of isoascorbyl palmitate synthesized by lipase in present study (400 MHz, DMSO-d6).The 13C NMR spectrum of isoascorbyl palmitate showed the carbonyl group at C-1 and double bonds in between C-2 and C-3 in isoascorbic moiety were intact which indicated that the enzymatic reaction occurred in other position. The C-6′ signal at 65.six ppm inside the synthesized isoascorbylester had a down-field shift of 3.9 ppm in comparison with that of isoascorbic acid (61.7 ppm). These benefits proved the presence of an ester bond on C-6of the isoascorbyl moiety and correspond using the pattern of chemical shift reported by Park et al. [8] and Stamatis et al. [19].Sun et al. Chemistry Central Journal 2013, 7:114 http://journal.chemistrycentral/content/7/1/Page 5 ofOne-factor-at-a-time experiments for isoascorbyl palmitate synthesis approach Effect of lipase supply on D-isoascorbyl palmitate synthesisLipases (E.C. 3.1.1.3) generally catalyze the hydrolysis of oils and fats [20,21]. Beneath certain conditions, in addition they ca.