TfOH/DMEDA-Mediated Cyclization of 2-(3-Arylthioureido)-amide to Form 2-Thioimidazoline-4-ones

A synthetic methodology for a series of 2-thioimidazoline-4-ones (4 a-4 u) was developed using trifluoromethanesulfonic acid (TfOH)/N,N '-dimethylethylenediamines (DMEDA) in dichloromethane. alpha-Aminoacetamides and isothiocyanates were used to prepare 2-(3-arylthiourea)amide (3 a-3 u), which was cyclized to produce the desired 2-thioimidazoline-4-ones with good to excellent yield (75 %-95 %). All the new compounds obtained were characterized by H-1 NMR, C-13 NMR and HRMS, and further corroborated by X-ray crystallography for 4 i, 4 o, 4 p.

Automated summary

A synthetic methodology for a series of 2-thioimidazoline-4-ones was developed using trifluoromethanesulfonic acid and N,N'-dimethylethylenediamines in dichloromethane. The new compounds were characterized by various spectroscopic techniques and X-ray crystallography for further confirmation. High yields were obtained during the cyclization process.