The synthesis of inward-facing 3,6-di(2-pyridyl)pyridazine ligands

• Published in: Tetrahedron letters Vol. 37; no. 16; pp. 2825 - 2828
• Main Authors: Butler, Douglas N., Tepperman, Paul M., Gau, Robert A., Warrener, Ronald N.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15-04-1996
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/0040-4039(96)00397-8

A new class of inward-facing bis(dpp-ligands) fused to rigid molecular racks are reported, eg
17 and
19. The 3,6-di(2-pyridyl)pyridazine ligand units are formed by the reaction of 3,6-di(2-pyridyl)
s-tetrazine with molrac bis(olefins), eg
11 and
18 (followed by oxidation of the intermediate dihydropyridazines); additionally mono-olefin, mono-pyridazines
14 and
21 are reported. Molecular modelling and comments of the mechanism of product formation are included.
Rigid mono-and bis-DPP ligands are formed from molrac olefins with tetrazine
1 and DDQ. The steps in the conversion of
11 to
14 and of
14 to
17 are followed by
1H NMR.