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19th January 2017 @ 13:09
 The aim of this experiment is to produce 2-piperidinylbenzaldehyde using a SNAr mechanism1.  This reaction was previously trialled on a smaller scale (AB-02-01). The previous experiment yielded the desired product but only a 28% yield. Therefore, the molar equivalents of the starting material have been altered to try to obtain a higher percentage yield. The same starting materials are being used; 2-fluorobenzaldehyde and Piperidine: Figure 1: Preparation of 2-piperidinylbenzaldehyde via SNAr. Table 1: Table of Reagents used in experiment. Reagent Equivalents Molecular Weight (g/mol) Density (g/mL) Moles (mmol) Quantities 2-fluorobenzaldehyde 1 124.11   1.178 8.8 1.10 g (0.933 mL) Potassium carbonate 1 138.205 - 8.8 1.20 g   Dimethylforamide (DMF) - - - - ~8 mL   Piperidine   1.5 85.15 0.862 13.2 1.14 g (1.322 mL)  Procedure To a stirred solution of DMF (8 mL), Potassium carbonate (1.20 g, 8.8 mmol) was added in a flask. 2-fluorobenzaldehyde (0.933 mL, 8.8 mmol) and Piperidine (1.322 mL, 13.2 mmol) were then added. The solution was heated and left under an air condenser for 12 hours. The resulting mixture changed from being pale yellow to dark  orange in colour. The mixture was then extracted into Diethyl ether (3 x 20 mL). the organic phases were combined and washed with Brine (10 mL).   Figure 2: Separating funnel showing the two layers present after washing. The organic phase was then dried (MgSO4), filtered and the solvent removed in vacuo to give the crude material as a yellow-orange solution The product was purified via silica column chromatography. The eluting mixture used was EtOAc/Pet. Ether 1:9. TLC analysis was undertaken (EtOAc/Pet. Ether 1:1) for each of the 20 fractions obtained. These were compared to the TLC taken to test whether the reaction had occurred. Spots 4, 5.2, 6.2 and 7.2 had Rf values of 0.66-0.68 which compared to the 0.64 obtained for the product initially, which suggested fractions 4-7 contained the product. Therefore, these were combined and dried under vacuo.  Figure 3: TLC taken for the 20 fractions; showing all spots seen. The resulting product was a yellow oily solution and a 35% yield was obtained. 1H NMR of the product was taken, which showed the presence of the desired product.   Figure 4: NMR spectra of fractions 4-7 combined.    Further data- [data]20522[/data][data]20524[/data][data]20526[/data][data]20532[/data] [data]20528[/data][data]20530[/data][data]20534[/data][data]20538[/data] References X. Xia, X. Shu, K. Ji, Y. Yang, A. Shaukat, X. Liu and Y. Liang, J. Org. Chem., 2010, 75 (9), 2893–2902