Mechanism of the dehydrogenation of the Hantzsch ether with pyridine N-oxide

Recent advances in the chemistry of dihydropyridines

“…The use of the same reagent on 1,4dimethyl-l,4-dihydropyridine (115b) followed by methyl iodide gave only the 2-methyl-l,4-dihydropyridine 117. Dihydropyridines not substituted on nitrogen are sufficiently acidic for the removal of the proton by strong base, such as sodium hydride or organometallics. Phase transfer catalysis has similarly been used to generate iV-alkyl-1,4-dihydropyridines (120)(121). 89 The nitrogen-unsubstituted 1,2-dihydropyridines 122…”

Structural features and near infra-red (NIR) luminescence of isomeric Yb(iii) bipyridyl-N,N′-dioxide coordination polymers

“…Shortly thereafter, the same authors prepared and structurally characterised an unprecedented eight connected lanthanide coordination network with the CsCl (4 24 ·6 4 ) network topology, 13 with recent work extending the chemistry of substituted 4,4′-bpdo ligands. 14 Interestingly then, although the isomeric 3,3′-bipyridine-N,N′-dioxide (3,3′-bpdo, Chart 1) compound is known 11,15 in the literature, it appears that its coordination properties with metal ions have never been explored. Due to free rotation about the central C-C bond, we noted that 3,3′-bpdo is able to coordinate linearly (180°, trans N-oxides) or with a more acute bond vector (∼60°, cis N-oxides) when acting as a bidentate ligand, and rationalised this may introduce additional structural diversity into its networks.…”