Ahm. Elwahy et al., Difunctional heterocycles: a convenient synthesis of bis(pyridinyl-2,3-dihydrooxadiazolyl)benzenes, J CHEM R-S, (5), 2001, pp. 175-178
Bis(pyridinyl-2,3-dihydrooxadiazolyl)benzenes 5a-e and 9a, b are obtained i
n 25-85% yields by heating the corresponding bis(hydrazones) 4a-f and 8a, d
in refluxing AC(2)O-AcOH for 3-5 h, while the bishydrazones 19 and 17b giv
e 33-54% yields of the phthalazine derivatives 20a, b upon heating in reflu
xing ethanol containing acetic acid.