•A one-stage fatty acid transmethylation method has been optimized for meat products.•A fast GC run for fatty acid analysis has been established.•Quality control parameters have shown an accurate ...performance of this methodology.•High recovery percentages of fatty acids have been found with the improved method.•A straightforwardly and quickly fatty acid analysis for meat products has been proven.
The quantification of fatty acids (FA) in meat products is frequently carried out by two-stage methylation procedures followed by long gas chromatography (GC) runs. This work aimed to simplify this methodology by means of a one-stage transmethylation method and a fast GC run, evaluating the influence of sample preparation, reagents and type of heating on the amount of FA in different meat products and optimizing a fast GC-FID (flame ionization detector) run. This allowed to establish the optimum combination of parameters (methanol + chlorotrimethylsilane, lyophilized samples and oven heating) to achieve the quantification of the highest possible amount of FA and to reduce the time of GC run from 60 to 10 min. The quality evaluation of this method obtained satisfactory results. Thus, the quantification of FA in meat products was achieved in a straightforwardly and quickly way by using a one-stage transmethylation procedure followed by a fast GC-FID run.
The electroreductive coupling of 2-acylbenzoates with acrylonitrile in the presence of TMSCl and successive treatment with 1 M HCl gave 2-cyanonaphthalen-1-ols or 3-(3-cyanoethyl)phthalides. On the ...other hand, the reaction of 2-acylbenzoates with methyl vinyl ketone under the same conditions produced 3-(3-oxobutyl)phthalides as the sole products. What determines the product selectivity was studied using DFT calculations.
An efficient regioselective deoxygenation of arylalkyl‐1,2‐diketones by the couple trimethylsilylchloride/sodium iodide has been reported. In all cases, the deoxygenation takes place on the carbonyl ...group (Cα=O) proximal to the aromatic ring in methylene chloride at room temperature in good yields, furnishing a series of variously functionalized alkylbenzylketones. A large range of functional groups were well tolerated on the ortho‐, meta‐ and para‐positions by this mild process regardless of their electronic effects, demonstrating the general character of the present methodology. The trimethylsilylchloride/sodium iodide reducing process was also successfully applied to reduce α‐ketoacid and α‐ketoester substrates.
A new protocol for the direct sulfonylation of benzylic, allylic and homoallylic alcohols with sodium arenesulfinates is described by using iron(III) chloride as a catalyst and chlorotrimethylsilane ...as an additive. This method requires no preactivation of alcohols. Surprisingly in the reaction with homoallyl alcohols nucleophilic addition of sulfinate anion, occurs at the terminal double bond instead of nucleophic substitution at the alcohol.
In this paper, a new method for oxidative chlorination of thiols to sulfonyl chlorides and sulfonamides using H
2
O
2
in the presence of TMSCl is reported. The excellent yields, short reaction times, ...excellent efficiencies, low costs, and easy separation of products are the most important advantages of this method.
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•One-flask cascade method for synthesis of the multi-substituted 1,2,4-triazoles.•The utility of method was performed to synthesize Rimonabant analogue 4c and LH-21 3.•Compound 4g ...showed better CB1 inhibition and selective than compound 4c and LH-21 3.•This study provides the basis for further development of a potent CB1 antagonist.
An efficient one-flask cascade method for synthesis of the multi-substituted 1,2,4-triazoles via chlorotrimethylsilane as a promoter was developed. Firstly, nitrilimines were transformed to hydrazonamides as intermediate in high yield by treatment with commercially available hexamethyldisilazane. Subsequently, the mixture was added with corresponding acyl chloride and heated in the presence of pyridine to give the corresponding multi-substituted 1,2,4-triazoles via chlorotrimethylsilane promoted heterocyclization reaction. The utility of method was demonstrated to synthesize CB1 ligands including Rimonabant analogue 4c and LH-21 3 for modeling study. All synthesized compounds were subjected to the cAMP functional assay of CB1/CB2 receptor. Especially, compound 4g enhanced the reversal of cAMP reduction by CP59440 than LH-21 and Rimonabant analogue in CHO-hCB1 cells. In addition, the docking results showed compound 4g fits the best position with CB1 receptor. However, the ability to penetrate brain-blood barrier of compound 4g is similar with Rimonabant in MDCK-mdr1 permeability assay, which might cause CNS side effect. This study still provides the basis for further development of a potent and specific CB1 antagonist.
•First substituted pyrazolo3,4-d-4,5-dihydropyrimidin-6-ones are reported.•The compounds are prepared by a new two-step procedure from commercial chemicals.•Up to four different groups are introduced ...into the title scaffold (19 examples).•Both, intermediates and the title species are easily purified by crystallization.•The reported method is suitable for the parallel synthesis of the title structures.
A small library of hitherto unprepared pyrazolo3,4-d-4,5-dihydropyrimidin-6-ones was synthesized on a preparative scale. The synthesis starts with a substituted 5-aminopyrazole that reacts with an isocyanate to give the corresponding urea. The latter undergoes a chlorotrimethylsilane-promoted 5+1 cyclocondensation with an aldehyde yielding the title pyrazolo3,4-d-4,5-dihydropyrimidin-6-one. Both synthetic steps are high-yielding (74–94%). The intermediates and the target compounds were isolated by simple crystallization. Ketones with the exception of isatin do not react with the open-chain urea intermediates.
Nitroso compounds are versatile reagents in synthetic organic chemistry. Herein, we disclose a feasible protocol for the ipso-nitrosation of aryl boronic acids using chlorotrimethylsilane–sodium ...nitrite unison as nitrosation reagent system.
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