Hexahydro-3-alkyl-3H-oxazolo[3,4-a]pyridines 4–15 for the quantitative analysis of various aldehydes were obtained in good yield via condensation reaction 2-hydroxymethylpiperidine (2-HMP) with under mild conditions. When acrolein was used, bicyclic 17 obtained. This novel compound has suitable physical characteristics an analytical standard. The hexahydro-3-vinyl-3H-oxazolo[3,4-a]pyridine 16 c...

Three symmetrical and unsymmetrical trans-dithienylethenes functionalized with pyridines and fluorenes have been synthesized by a facile one-pot procedure, and their characteristics and photochromism were investigated. Their fluorescent intensity was efficiently regulated by a photochromic switch using alternative irradiation with UV light and visible light. Moreover, by protonation and complex...

A convenient one-pot reaction was conducted by mixing bromoacetophenone, a functionalized α,β-unsaturated ketone and potassium hydroxide in tetrahydrofuran at room temperature, ammonium acetate was added and heated to reflux, resulting in four chemical bonds forming from easily accessible substrates. This process provides a flexible and rapid synthetic route for the construction of polysubstitu...

A number of 4-aryl- and 4-alkynyl-substituted 6H-1,2-oxazines 8 and 9 have been prepared in good yields via cross coupling reactions of halogenated precursors 2, which in turn are easily accessible by bromination of 6H-1,2-oxazines 1. Lewis-acid promoted reaction of 1,2-oxazine 9c with 1-hexyne provided alkynyl-substituted pyridine derivative 12 thus demonstrating the potential of this approach...

Iodine-catalyzed regioselective sulfenylation of imidazo[1,2-a]pyridines via C(sp(2))-H bond functionalization has been achieved using sulfonyl hydrazides as a thiol surrogate. A library of 3-sulfanylimidazopyridines with broad functionalities was synthesized under metal and oxidant-free practical reaction conditions. This methodology is also applicable for the regioselective sulfenylation of i...

The synthesis of dipyrazolo[1,5-a:4',3'-c]pyridines is described. Easily obtainable 5-alkynylpyrazole-4-carbaldehydes, p-toluenesulfonyl hydrazide, and an aldehyde or ketone containing an α-hydrogen atom were reacted in a silver triflate catalyzed multicomponent reaction affording new tricyclic compounds with a dipyrazolo[1,5-a:4',3'-c]pyridine core. Detailed NMR spectroscopic investigations ((...