Chemical Properties
White Solid
Uses
Sodium Methanethiosulfonate (cas# 1950-85-2) is a compound useful in organic synthesis.
Synthesis
The general procedure for the synthesis of sodium sulfur methanesulfonate from sodium methanesulfite was as follows: a mixture of sodium methanesulfonate (5.43 g, 53 mmol) and sulfur powder (1.666 g, 52 mmol) in anhydrous methanol (310 mL) was heated and refluxed for 20 minutes until the sulfur was almost completely dissolved. The reaction mixture was filtered while hot and the filtrate was concentrated to dryness. The resulting off-white solid was stirred with a small amount of anhydrous ethanol at room temperature, filtered and concentrated again. The grinding process was repeated until the 1H NMR spectrum of the white residue showed no sodium methanethiosulfonate residue. All the filtrates were combined and evaporated to dryness to give sodium thiomethanesulfonate (5.40 g, 77% yield) as fine white acicular crystals; melting point 271-272°C (literature value: 272-273.5°C, G.L. Kenyon, T.W. Bruice, Methods Enzymol. 1977, 47, 407-430); 1H NMR ( 200 MHz, CDCl3) δ 3.18 (s, 3H, CH3); Calculated elemental analysis (C8H5NaO2S2): C 8.95, H 2.25; Measured values: C 8.86, H 2.55.
An improved synthetic method for NaMTS has been successfully validated, which achieves a high yield synthesis of NaMTS through the reflux reaction of sodium sulfite with sulfur in methanol (Scheme 16, Figure 19), avoiding the cumbersome by-product isolation step in the conventional Na2SZMe3SiCl method. Although a small amount of unknown by-products was generated during the reaction, they were easily separated from NaMTS.
Purification Methods
Recrystallise the salt from H2O (plates as monohydrate) or MeOH. The potassium salt crystallises from H2O, EtOH or MeOH (thick plates) with m 201-202o [Foss Acta Chem Scand 10 868 1956]. The S-benzylisothiouronium salt has m 141-142o (from EtOH) [Kurzer & Powell J Chem Soc 3733 1952]. [Beilstein 4 IV 31.]
References
[1] Chemistry Letters, 1987, p. 2161 - 2162
[2] Patent: WO2006/55437, 2006, A2. Location in patent: Page/Page column 38; 39; sheet 23
[3] Journal of Organic Chemistry, 2005, vol. 70, # 24, p. 9740 - 9754
[4] Dalton Transactions, 2011, vol. 40, # 45, p. 12310 - 12319
[5] Journal of Organic Chemistry, 1988, vol. 53, # 2, p. 396 - 402
