Methyl 3-arylamino-2-benzoylaminopropenoates in the synthesis of 4-arylaminomethylene-2-oxazolin-5-ones: Unexpected formation of bis-oxazolones

摘要

The reaction of methyl 3-arylamino-2-benzoylaminopropenoates 2 with phosphorus oxychloride in pyridine at 70 deg C for 30 min leads to the unexpected formating of N-aryl-N-bis-(5-oxo-2-phenyl-4,5-dihydro-oxazol-4-ylmethylene) amines 4.