Syntheses of 5,5′-Disubstituted 2,2′-Bipyridines

Abstract

New and improved syntheses of 5,5′-donor-functionalized 2,2′-bipyridines are reported with the 5,5′-donors being -NH₂ (4), -NMe₂ (5), -CN (6), and -NCS (7). A new route for 4 and 5 is based on the coupling of 2-chloro-5-amino-pyridine in the presence of NiCl₂ · 6 H₂O/PPh₃/Zn in DMF (NiCRA). 6 was obtained by a dehydration treatment of 5,5′-dicarboxamide-2,2′-bipyridine with (F₃CO)₂O and P₄O₁₀. The new ligand 7 is prepared from 4 and SCCl₂.

Key Words:

• biaryls
• coupling reactions
• pyridines
• cyano compounds
• isothiocyanates