Ahm. Elwahy, Difunctional heterocycles: a convenient synthesis of bis(4,5-dihydropyrazolyl) ethers from their precursor bis(chalcones), J CHEM R-S, (10), 1999, pp. 602-603B
Bis(4,5-dihydropyrazolyl) ethers 18-22, 26, 27 and 40-44 are obtained in 35
-80% yield by heating the corresponding bis(chalcones) 13-17 and 34-37 with
each of hydrazine hydrate and phenylhydrazine in refluxing acetic acid.