849020-94-6

• Two-step syntheses of fused quinoxaline-benzodiazepines and bis-benzodiazepines employing a double UDC (Ugi/Deprotect/Cyclize) strategy
• Preparation of hydroquinazoline scaffolds via microwave-promoted Ugi reaction and cyclization
• Preparation of pyrazinone inhibitors of mast cell tryptase

24424-99-5

4403-69-4

849020-94-6

Example 1 Synthesis of tert-butyl N-[2-(aminomethyl)phenyl]carbamate: To an anhydrous dichloromethane (30 mL) solution of 2-aminobenzylamine (2.440 g, 20.0 mmol), an anhydrous dichloromethane (12 mL) solution of di-tert-butyl dicarbonate (4.360 g, 20.0 mmol) was slowly added dropwise over a period of minutes at room temperature. The progress of the reaction was monitored by thin layer chromatography (TLC) with ethyl acetate: hexane (1:1) as the unfolding agent, and the completion of the reaction was confirmed after about 30 minutes. Subsequently, the volatile solvent was removed by rotary evaporation, and the resulting solid was purified by fast column chromatography with the eluent ethyl acetate-hexane (initial ratio 1.5:8.5, gradually adjusted to 3:7), resulting in tert-butyl N-[2-(aminomethyl)phenyl]carbamate 3.912 g in 88% yield as an off-white powder, with spectral and analytical data as expected.