An Efficient and Chemoselective Synthesis of 1,6-Naphthyridines and Pyrano[3,2-c]pyridines under Microwave Irradiation

Abstract

A series of 1,6-naphthyridines and pyrano[3,2-c]pyridines were selectively synthesized via microwave-assisted reactions controlled by the nature of the solvent. This has resulted in an efficient and promising synthetic method for constructing the 1,6-naphthyridine and pyrano[3,2-c]pyridine skeletons.

Key words

solvent-dependent chemoselectivity - 1,6-naphthyridines - pyrano[3,2-c]pyridines

References

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10

The single-crystal growth was carried out in ethanol at room temperature. X-ray crystallographic analysis was performed with a Siemens SMART CCD and a Siemens P4 diffractometer (graphite monochromator, MoKα radiation, λ = 0.71073 Å). Crystal data for 4i: empirical formula = C₂₅H₂₀N₄S₂, formula weight = 440.57, crystal dimensions = 0.13 × 0.12 × 0.03 mm, monoclinic, space group P2(1)/n, a = 11.0619(12) Å, b = 11.2598(13) Å, c = 17.5329(19) Å, α = 90, β = 93.6620(10), γ = 90, µ = 0.265 mm^-¹, V = 2179.3(4) Å^³, Z = 4, D _c  = 1.343 g/cm^³, F(000) = 920, S = 0.808, R ₁ = 0.0665, wR ₂ = 0.0863.