Please find the information about the canolol from the previous post.
All the information below is a part of my article in Journal of Agricultural and Food Chemistry (J. Agric. Food Chem. 2012, 60, 30, 7506–7512). For details, please read the original article
In this post, we will focus our discussion on the chemistry of canolol. First, we will discuss the chemical synthesis in the laboratory. Afterwards, we will discuss NMR (Nuclear Magnetic Resonance) spectroscopy and mass spectrometric methods to confirm the structure of the synthesized compounds.
Chemical synthesis
Canolol was synthesized from Syringaldehyde by reacting with Malonic acid in the presence of Acetic acid and Piperidine under microwave condition. The chemistry of the reaction is shown in the Figure. The reaction involves series of condensation, dehydration and decarboxylation steps. Microwave supports the formation of polar intermediates during the reaction. The synthesized canolol was purified using a silica gel column chromatography. Crystallization was applied as an additional step to increase the purity. A saturated solution of the synthesized compound in hexane was prepared at ambient temperature, and crystallization was induced by storing it inside the freezer (−28 °C). Crystals (white) were separated from the mother liquor and dried under nitrogen. The structure of the purified compound was confirmed by NMR and mass spectrometry.
Figure: chemical synthesis of canolol from syringaldehyde
NMR Spectroscopy:
NMR Chemical Shifts of the compound is shown below. The position of the proton responsible for different NMR spectra has been indicated in the table. The NMR spectroscopy confirms the structure of the purified compound as canolol.
Liquid Chromatography−Time of Flight Mass Spectrometry (LC−TOF MS) :
The LC-MS spectra indicated different fragments of the compound having m/z values of 203.06, 181.08, 166.06, 149.06, 121.06 and 103.05. The ms fragmentation pattern of the compound has been shown in the figure below.
Both the NMR and LC-TOF MS confirmed the structure of the synthesized compound. Canolol can be used in functional foods, Nutraceutical products, pharmaceutical products, chemicals industries etc. The compound is known to be formed during roasting of mustard and rapeseed. The roasted mustard and rapeseed oil is a good source of canonol. Roasted oil is an integral part of the Newari cuisines. Researchers from Canada and Germany have already started developing a commercial technology for the manufacturing of this compound.
Canolol as a potent antioxidant
Canolol is a potent antioxidant. The antioxidant property of the canolol is due to its’ radical scavenging activity. Canolol can easily donate a proton to the free radical to form a stable resonance structures. The mechanism of radical scavenging activity of this compound is shown in the figure below.
For those interested in the methodology:
NMR Spectroscopy:
The purified compound was dissolved in deuterated chloroform. The proton (1H) and carbon (13C) NMR spectra were taken using a Jeol EX300 Eclipse NMR (300 MHz) spectrophotometer (Japan).
Liquid Chromatography−Time of Flight Mass Spectrometry (LC−TOF MS) Spectroscopy :
The LC−MS analysis of the purified compound was carried out using UltiMate 3000 ultrahigh-pressure liquid chromatography (UHPLC, Dionex) equipped with a degasser, four solvent delivery modules, an autosampler, a column oven, and an UV detector coupled with a MicroTOF MS instrument (Bruker). The purified compound was dissolved in an isopropanol/water/acetic acid (90:10:0.1, v/v/v) mixture (10 μg/mL) and then injected on a C8 Zorbax 300 SB column (Agilent, Santa Clara, CA). Mobile phase A was a water/acetonitrile/acetic acid mixture (90:10:0.1, v/v/v), and mobile phase B was an acetonitrile/ water/acetic acid mixture (90:10:0.1, v/v/v). The method was run with 10% mobile phase B for 1 min, then a gradient was applied to reach 100% of mobile phase B in 11 min, which was held for 5 min. Afterward, the initial conditions were reached in 0.5 min, and the column was allowed to equilibrate for 4.5 min before a subsequent analytical run. The solvent flow rate was 0.2 mL/min. Electrospray ionization (ESI) in positive-ion mode was used, and m/z values were scanned from 50 to 1000. The capillary voltage was set at 4500 V, and the end plate offset was at −500 V. The nebulizer pressure was 0.5 bar and was heated to 190 °C with dry nitrogen at a flow rate of 4 mL/ min.
All the information above is a part of my article in Journal of Agricultural and Food Chemistry (J. Agric. Food Chem. 2012, 60, 30, 7506–7512). For details, please read the original article. Contact me if you have trouble accessing it.
Please find the information about the canolol from the previous post.
Read the original article below:
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