A Convenient Synthesis of 2,2′,6,6′-Tetramethyl-4,4′-bipyridine and Its Oxidation to 2,2′,6,6′-Tetracarboxy-4,4′-bipyridine

Catalytic reduction of dinitrogen to ammonia at a single molybdenum center

“…Although we have not yet identified the initial reduction product, preliminary NMR evidence suggests that after workup of the 2,6-lutidinium reduction in air, the product is the bipyridine formed through coupling in the para position of 2,6-Lut. This bipyridine can be prepared through reduction of 2,6-Lut with sodium followed by treatment of the reaction with SO 2 (21). However, the electron balance for production of dihydrogen and ammonia in catalytic runs suggest that this bipyridine is not formed to any significant extent under catalytic conditions.…”

2,2′,6,6′-Tetramethyl-4,4′-bipyridine

“…For the synthesis of the title compound, see: Hunig & Wehner (1989). For related compounds, see: Coles et al (2002); Jackisch et al (1990); Lin et al (2006).…”

Cocondensation reactions of nitrogen-containing heterocycles with lithium atoms at 77 K

“…The main one (38% yield) was characterised as 4,4 0 -bilutidine (14) [13], therefore lithium atoms do not appear bonded (Scheme 4). The second product (13) was obtained in lower yield (4%) and was identified as a lithium-containing compound. The lithium is found bonded through the nitrogen and two rings are connected in the para position, which leads to a dimeric hexadiene.…”

“…The general procedure applied to 2,4,6-collidine (9) gave 1,1 0 -dilithio-2,4,6,2 0 ,4 0 ,6 0 -hexamethyl-1,4,1 0 ,4 0 -tetrahydro-[4,4 0 ]-bipyridinyl (10) (red colour) in 35% yield, which was identified as its TMS derivative: 1 The general procedure applied to 2,6-lutidine (11) gave 1,1 0 -dilithio-2,6,2 0 ,6 0 -tetramethyl-1,4,1 0 ,4 0 -tetrahydro-[4,4 0 ]-bipyridinyl (13) (red colour) in 4% yield, which was identified as its TMS derivative: 1 H NMR (CDCl 3 ) d = 0.09 ppm (s), d = 2.55 ppm (s), d = 3.28 ppm (t, J = 6 Hz), d = 4.35 ppm (d, J = 6 Hz); 13 C NMR (CDCl 3 ) due to the low yield of this reaction, the compound could not be identified using 13 C NMR spectroscopy. The general procedure applied to 2-methoxy pyridine (14) gave 1,1 0 -dilithio-2,2 0 -dimethoxy-1,4,1 0 ,4 0 -tetrahydro-[4,4 0 ]-bipyridinyl (15) (dark yellow colour) in 8% yield, which was identified as its TMS derivative: (CDCl 3 1 H NMR) d = 0.08 ppm (s), d = 3.47 ppm (m), Table 4 Crystal data and structure refinement of 10b 13 C NMR (CDCl 3 ): due to the low yield of this reaction and the low concentration of the analysed compound, not all carbons could be found in the 13 C NMR spectra, 13 …”