No abstract

We develop a tandem protocol to synthesize unsymmetrical sulfoximine-based urea via Curtius rearrangement. The aliphatic/aromatic acid in the presence of diphenylphosphorylazide (DPPA) undergo Curtius rearrangement, and subsequent nucleophilic attack with sulfoximine provides corresponding urea derivative in very good to excellent yield. The protocol is equally applicable for gram-scale synthesis. The direct use of cheap, easy handling, commercially available aliphatic/aromatic acids are the main advantages of this method. Additionally, we synthesize the sulfoximine analogue of key biologically active compounds, such as tolbutamide, chlorpropamide, and oncolytic sulfonyl urea.