Oxidation of aromatic compounds: VII. Oxidation of symmetrically substituted 1,3-diarylpropynones in the system CF3COOH-CH2Cl2-PbO2. New synthesis method of 1,1,2,2-tetraaroylethenes
Av. Vasil'Ev et al., Oxidation of aromatic compounds: VII. Oxidation of symmetrically substituted 1,3-diarylpropynones in the system CF3COOH-CH2Cl2-PbO2. New synthesis method of 1,1,2,2-tetraaroylethenes, RUSS J ORG, 36(8), 2000, pp. 1157-1162
Preparative oxidation of 1,3-diarypropynones ArC=CCOAr in a system CF3COOH-
CH2Cl2-PbO2 at 18-20 degreesC within 1.5-25 h results in 1,1,2,2-tetraaroyl
ethenes (ArCO)(2)C= C(COAr)(2) in yields up to 75%. The most easily and eff
iciently the products form from the substrates where the aryl moiety conjug
ated with the triple bond contains electron-donating substituents p-MeO, p-
Me, and p-t-Bu. On heating with hydrazine 1,1,2,2-tetrakis(4-methoxyphenylc
arbonyl)ethene is converted into heterocyclic structures: pyridazine and 2,
3,6,7-tetraazanaphthalene derivatives.