A new synthesis of α-oxoketene O,N-acetals has been developed from β-oxothioxo esters. Thus, the reaction of 2a-c with alkyl, allyl or cyclic primary amines in refluxing toluene and formic acid led to α-oxoketene O,N-acetals 3a-i in good yields.
A series of 1,5-diphenyl-1 H-pyrazol-3-amines, 3-ethoxy-5-phenyl-1 H-pyrazole, 5-ethoxy-1,3-diphenyl-1 H-pyr-azole and 3-ethoxy-1,5-diphenyl-1 H-pyrazole were efficiently prepared from the regiocontrolled cyclization of α-oxoketene O, N-acetals and/or β-oxo thioxoesters with hydrazine derivatives using montmorillonite K-10 as solid support with ultrasound. The antimicrobial activity of the heterocyclic
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.
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.