the 2-mono and 2,6-disubstituted methyl-1,4-dihydropyridines were synthesized by reaction of morpholine, thiophenol, 8-hydroxyquinoline, 2-naphthol and 2-mercopto-1-methyl imidazole with the 2-mono bromo and 2,6-dibromo-1,4-dihidropyridines.

oxidation of different types of 1,4-dihydropyridines with diphenylpicrylhydrazyl (dpp) and benzoyl peroxide (bz2o2) as free radical oxidizing agents to pyridine derivatives is reported and a mechanism for this oxidation is also proposed.

Reactions of 1 ,Zdihydropyridines (la-c) and 1,4-dihydropyridines (2a-c) in the presence of benzyne (3) under thermal conditions, and in the case of (2c) under photochemical conditions, have been investigated. Benzyne acts as an oxidizing agent to convert dihydropyridine (la) and (2a) to the corresponding pyridine (4) or adds as a dienophile to (lb-c).

The palladium-assisted one-pot three-component reactions of aldehydes, amines and olefins proceeded smoothly to give 2,6-unsubstituted 1,4-dihydropyridines (1,4-DHPs) using molecular oxygen as a sole oxidant. It also provides efficient Pd-catalyzed aerobic oxidation access to the anti-Markovnikov oxidative amination products of olefins from primary aromatic amines and alkenes. The method is ato...