Synthesis and crystal structure of N-phenyl-N′-(pyridin-2-ylmethyl)-S-methyl-thiouronium iodide

Methylation of N-phenyl-N′-(pyridin-2-ylmethyl)thiourea led to a new low melting thiouronium iodide salt, whereas a further methylation of the nitrogen of the pyridine ring was not successful. This could be explained by the inactivity of the nitrogen atom due to the sterical shielding revealed by crystallographic data. Exchange of the iodide anion with bis(trifluoromethylsulfonyl)imide led to a thiouronium room temperature ionic liquid. Methylation of the urea analog N-phenyl-N′-(pyridin-2-ylmethyl)urea occurred on pyridine nitrogen, resulting in the expected pyridinium salt.