General Procedure for Urea Synthesis through an Isocyanate (1–13) (General Procedure C)

The corresponding isocyanate (1.2 equiv) was added to a solution of the corresponding amine (1 equiv) dissolved in dry THF (10 mL) and stirred overnight. The reaction was quenched with 1 N HCl (10 mL) and stirred for 5 min. The reaction was neutralized by addition of Na₂CO₃ and extracted three times with EtOAc. The product was further purified by flash chromatography to afford the product.