Lawesson's reagent → HCID 54201267, compound

Participants

Reaction Steps

Lawesson's reagent (5.26 g.) was added to a boiling solution of 8H-thiazolo[3,2-a]pyrimidin-7-one (4.0 g.) in CH3CN(200 ml.) and the mixture was heated under reflux with stirring for 1.5 h. On cooling silica gel (70-230 mesh, 15 g.) was added and the mixture was evaporated to dryness. The residue was applied to a column of silica gel (300 g.) and eluted with MeOH/CH2Cl2 (5-10% to give 8H-thiazolo[3,2-a]-pyrimidin-7-thione (2.7 g.). Trimethyloxonium tetrafluoroborate (2.0 g.) was added to a stirred suspension of 8H-thiazolo[3,2-a]pyrimidin-7-thione (1.5 g.) in dry CH3CN (50 ml.). After stirring for 2 h, the solution was concentrated to about 20 ml., and with vigorous stirring anhydrous ether (100 ml.) was added to precipitate 7-methylthiothiazolo[3,2-a]-pyrimidinium tetrafluoroborate (1.3 g.), having nmr in d6DMSO:

Provenance & Evidence