1. A reinvestigation of the reaction between dibenzoylethylene and orthophenylenediamine
2. J. Org. Chem. USSR, 6, 1110 (1970).
3. A third compound initially isolated was found to be 2-phenyl-3-methylquinoxaline. However, in subsequent runs it was not obtained. We therefore ascribe its presence to an impurity in one sample of starting material.
4. “Sadtler Standard Spectra”, Sadtler Research Laboratories, Philadelphia.