Mild Synthesis of α-Oxoketene O.N-Acetals from β-Oxothioxo Esters and Amines
摘要:
alpha-Oxoketene O,N-acetals were prepared from beta-oxothiono esters and primary amines in the presence of triethylamine at room temperature within several hours in good yields.
A novel method for the synthesis of N-alkyl-3-acyl-4-alkoxycarbonylmethylpyrrolidine-2,5-diones (3) was accomplished. α-Oxoketene O,N-acetals (1) reacted with maleicanhydride (2) at 80–110 °C for 5 h without solvent to give 3 in moderate to good yield (36–74%). Single X-ray crystallographic analysis showed that the two substituents on C-3 and C-4 were trans.