Thiations with sulphur in dimethylformamide

A solution of sulphur in boiling dimethylformamide is a convenient thiation agent. Activated hydrogen and halogen atoms are replaced by thiol groups and further reactions may then occur, often involving dimethylamine liberated from the solvent. However, since the amine is present only in low concentrations, products are sometimes isolated which are formed only in small quantity in the presence of an excess of amine.