Triethylamine → Methyl thieno[2,3-b]pyridine-2-carboxylate

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Reaction Steps

To 2-chloro-3-pyridine carboxaldehyde, compound 147-A, (5.07 g, 35.8 mmol), dissolved in MeCN (30 mL) was added triethylamine (6.5 mL, 46.5 mmol) followed by methyl thioglycolate (3.49 mL, 38.3 mmol) and the reaction was refluxed for 18 h. The reaction mixture was cooled and the solvent evaporated under reduced pressure. The crude residue was partitioned between H2O and EtOAc, the layers separated and the aqueous phase extracted with EtOAc. The organic layers were combined, washed with H2O, brine, dried over Na2SO4, filtered, and the solvent evaporated under reduced pressure. The crude residue was purified by flash column chromatography (SiO2) eluting with a heptane-EtOAc gradient to afford compound 147-B as a white solid (2.01 g, 29%). 1H-NMR (DMSO-d6): δ 3.91 (s, 3H), 7.54-7.57 (m, 1H), 8.23 (s, 1H), 8.43-8.46 (m, 1H), 8.72-8.74 (m, 1H); MS: m/z 194.1 (MH+).

Provenance & Evidence