Dipodal (2+2) condensation of 3,5-(1H-pyrazole)dicarbaldehyde (3) with 1,5-diamino-3-oxapentane (4) and diethylenetriamine (5) followed by hydrogenation of the resulting Schiff bases (6 and 8), affords two new 26 membered polyaza macrocycles of 1H-pyrazole (7 and 9). The deprotonation of both crowns in basic medium as well as the formation of dinuclear Zn2+ complexes (7b and 9b) from the dipyrazolate salts 7a and 9a have been studied by 13C NMR.

This work wss supported by the Comision Interministerial de Ciencia y Tecnologia (CICYT, Plan National I+D, Proyect FAR-90-0745). One of us (Dr M. Kumar) is grateful to the Spanish Ministry of Education and Science for a postdoctoral grant and to the D.A.V. Managing Commitee of Hoshiarpur (India) for granting study leave.