Pd-Catalyzed C-H arylation of pyridazine-based fused 1,2,4-triazoles: overriding selectivity at the usual position by undermining of preferred chelate formation.

The applicability of C-H functionalization to medicinally important 2-pyridyl-based N-heterocycles suffers from severe challenges owing to the high Lewis basicity of the N-atom. This arrests catalytic activity and yields undesirable positional selectivity due to preferential chelate formation. In this regard, we report a novel palladium(ii)-catalyzed arylation strategy on multiple-N-containing pyridazines by over-riding the functionalization due to a chelated palladacycle. We report a regioselective mono-arylation at the 8-position of diphenyl azolopyridazines without any ortho-C-H activation on the proximal phenyl groups. This methodology presents a broad arylation scope with uncompromised yield and positional selectivity, including the heteroarylation of N-heterocycles, which is an unprecedented feat for these types of molecules.

Piperidone derivative from Dalbergia sympathetica.

An alcoholic extract of Dalbergia sympathetica, on column chromatography, yielded a compound which analyzed for C(6)H(11)NO(3) (M(+) 145). The IR spectrum of the compound showed the presence of carbonyl and hydroxyl groups. PMR, (13)C and DEPT NMR spectral studies of the compound showed the presence of one N-methyl, two methine and two methylene groups. A quaternary carbon signal at delta 172.88 ppm was assigned to C-2 carbonyl of the compound. From all the above observations and also from the HMQC 2D NMR spectrum, the compound was identified as 3, 6-dihydroxy-N-methyl-2-piperidone. This is the first report of the natural occurrence of this compound from plant sources.