2-Mercaptoethanol (1.09 g, 13.9 mmol) was dissolved in dry hexamethylphosphoryltriamine (HMPA, 3 mL), and sodium hydride (NaH, 0.40 g, 16.7 mmol) was added batchwise under nitrogen protection over 30 minutes. After addition, the reaction mixture was continued to be stirred for 10 min, followed by dropwise addition of 2-bromopyridine (2.00 g, 12.7 mmol). The reaction mixture was stirred at room temperature for 18 hours, then warmed up to 40 °C and continued stirring for 24 hours. Upon completion of the reaction, the reaction was quenched by slow addition of water (20 mL) and the aqueous phase was extracted with dichloromethane (3 x 15 mL). The organic phases were combined, dried over anhydrous magnesium sulfate (MgSO4), filtered and concentrated under reduced pressure to give a yellow oily crude product (5.53 g). Purification by silica gel column chromatography (eluent: ether/hexane, 4:1) afforded 2-(pyridin-2-ylthio)ethanol (19) as a yellow oil (purity ~95%, 1.54 g, yield ~72%). The product was characterized by the following data: infrared spectrum (νmax, neat, cm?1): 3362 (broad peak), 2929, 2864, 1580, 1557, 1455, 1415, 1283, 1232, 1149, 1045, 1016, 942, 878, 758, 724. 1H NMR (300 MHz, CDCl3): δ 3.31 (t, J = 5.5 Hz, 2H, H2), 3.93 (t, J = 5.5 Hz, 2H, H1), 7.00 (ddd, J = 7.4, 5.0, 1.1 Hz, 1H, H5'), 7.25 (dt, J = 8.1, 1.0 Hz, 1H, H3'), 7.48 (ddd, J = 8.0, 7.4, 1.9 Hz 1H, H4'), 8.35 (ddd, J = 5.0, 1.8, 1.0 Hz, 1H, H6'). 13C NMR (75 MHz, CDCl3): δ 33.9 (C2), 63.2 (C1), 119.9, 122.8 (C3', C5'), 136.4 (C4'), 148.9 (C6'), 158.8 ( C2'). Mass spectra (ESI): m/z 155.8 [M + H]+ (55%), 137.8 (100%). High-resolution mass spectrum (ESI+, MeOH): calculated value C7H10NOS [M + H]+ m/z 156.0483, measured value 156.0534. All spectral data are in agreement with literature reports. The conversion of alcohol 19 was 54% (as determined by 1H NMR spectroscopy) when the reaction time was extended to 25 h under the same reaction conditions.
