Methanesulfonic Acid → 4-Methylthio-N-(2-mercaptoethyl)pyridinium methanesulfonate

Participants

Reaction Steps

4-Methylthiopyridine (2.75 g, 22.0 mmol) was added slowly to methanesulfonic acid* (0.65 mL, 10.5 mmol) by cooling in an ice-bath. To this solid was added ethylene sulfide* (0.66 mL, 11.0 mmol, Aldrich) and the mixture was heated at 50°-60° C. for 21 h. As reaction proceeds the solid went to solution. After cooling, the reaction mixture was dissolved in H2O (5 mL) and washed with Et2O (5×4 mL). The cloudy aqueous layer was filtered over Celite and the filtrate was purified by reverse phase silica gel column chromatography (C18 micro bondapack 10 g) eluting with H2O. Each fraction of 10 mL was collected. Fractions 2 and 3 were combined and repurified by the reverse phase column. Fraction 2 gave 1.258 g (4.48 mmol, y. 42.6%) of the title compound as a viscous oil: 1Hmr (DMSO-d6, CFT-20) δ: 2.32 (3H, s, MeSO3⃝), 2.72 (3H, s, --SMe), 2.68 (1H, m, SH), 2.9-3.2 (3H, m, --CH2S--), 4.59 (2H, t, J=6.4 Hz, --CH2N⊕), 7.97 (2H, "d", J=7.2 Hz, aromatic-Hs) and 8.72 ppm (2H, "d", J=7.2 Hz, aromatic-Hs); ir (neat) νmax : 1630, 1200 (br, --SO3⃝), 785 and 770 cm-1.

Provenance & Evidence