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Williamson etherification using a hydroxypyridine; 5-(Propargyloxy)picolinaldehyde

SyntheticPage 555
DOI: 10.1039/SP555
Submitted Apr 10, 2012, published Apr 16, 2012
Suzanne Elizabeth Howson (s.e.howson@warwick.ac.uk)
A contribution from Scott group, Warwick University


			Reaction Scheme: <IMG src="/images/empty.gif">Williamson etherification using a hydroxypyridine<IMG src="/images/empty.gif">

Chemicals Used

Potassium carbonate (Fisher Scientific)
5-(Hydroxy)picolinaldehyde (SyntheticPage 549)
Dimethylformamide - DMF (Fisher Scientific)
Propargyl bromide - 80% in toluene (Sigma-Aldrich)
Chloroform (Fisher Scientific)

Procedure

Potassium carbonate (0.59 g, 4.26 mmol, 1.05 eq.) was added to a solution of 5-(hydroxy)picolinaldehyde (0.50 g, 4.06 mmol, 1.0 eq.) in DMF (15 ml). Propargyl bromide (80% in toluene, 0.475 ml, 4.26 mmol, 1.05 eq.) was added to the reaction via syringe. The round bottomed flask was fitted with a condenser and the solution was stirred at 100°C for 4 h before allowing to cool to ambient with stirring for an additional 1 h. The solvent was then removed under reduced pressure. The crude solid was then taken up in chloroform (150 ml) and filtered. This process was repeated a further two times (2 × 40 ml). The chloroform was then removed from the filtrate under reduced pressure to leave an orange solid, which was dried overnight in vacuo. Yield = 0.32 g, 1.99 mmol, 49%.

Author's Comments

Reaction has been carried out using this method with a number of different organic halides.

Data

1H NMR (400 MHz, 298 K, DMSO) δH 9.90 (1H, s, C=O), 8.53 (1H, d, 4JHH = 3.0 Hz, Py), 7.97 (1H, d, 3JHH = 8.5 Hz, Py), 7.64 (1H, dd, 3JHH = 8.5 Hz, 4JHH = 3.0 Hz, Py), 5.05 (2H, d, 4JHH = 2.5 Hz, CH2-C≡C), 3.71 (1H, t, 4JHH = 2.5 Hz, C≡CH).

13C{1H} NMR (100 MHz, 298K, DMSO) δC 191.9 (C=O), 156.7 (Py), 146.1 (Py), 138.8 (Py), 123.3 (Py), 121.7 (Py), 79.4 (C≡CH), 78.9 (C≡CH), 56.3 (CH2).

MS (ESI) 162.2 [M+H]+, 184.1 [M+Na]+.

IR ν cm-1: 3213 w, 2127 w, 1692 s, 1569 s, 1490 w, 1474 w, 1379 w, 1308 m, 1282 w, 1259 s, 1203 s, 1132 m, 1006 s, 975 m, 916 w, 835 s, 800 s, 762 m, 732 m, 694 s, 659 s.

Elemental Analysis found (Calculated for C9H7NO2) % C 66.85 (67.07), H 4.02 (4.38), N 8.52 (8.69).


Supplementary Information

e.g. Actual NMR spectra (as images or jdx files for interactive spectra), photographs of apparatus, TLC’s or crystals or videos. Please contact the ChemSpider team (ChemSpider-at-rsc.org) for help with this.
1H NMR spectrum (SEH503_1HNMR.jcamp)
13C NMR spectrum (SEH503_13CNMR.jcamp)

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Keywords: addition, alcohols, alkyl/alkenyl/aryl halides, alkynes, aromatics/arenes, etherification, ethers, nucleophilic, substitution, Williamson