2-Carbethoxymethyl-4H-3,1-benzoxazin-4-one. 3. Condensation of o-phenylenediamive

3-(2-Benzimidazolyl)-4-hydroxy-2-quinolone was unexpectedly obtained as the principal reaction product on fusion of 2-carbethoxymethyl-4H-3,1-benzoxazin-4-one with o-phenylenediamine. A possible mechanism of its formation is presented.For Communication 2 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 239–241, February, 1992.