Once again the question of cyclization of pyrazolones-5 unsubstituted at the nitrogen into tripyrazolylenes

Article abstract of DOI:10.1007/BF02290950

The experimental data were refined and the yields were improved significantly in cyclization of pyrazolones-5 into tripyrazolylenes-1,5 with phosphorus oxychloride. 1998 Plenum Publishing Corporation.