A. Guiotto, G. Bandoli, P. Manzini
Jun 1, 1987
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Journal
Journal of Crystallographic and Spectroscopic Research
Abstract
Treatment of dimethylated psoralen and angelicin in the 4′, 5′-position leads to the formation of 1,3-dioxane derivatives, resulting from the condensation of an 1,3-dioxane ring to the 4′, 5′-positions of the dihydrofurocoumarin moiety. The structures of these new compounds, 4a, 1 1a-dihydro-4a, 11a-dimethyl-8H-pyrano [3′, 2′∶5,6]benzofuro[3,2-e]-1, 3-dioxan-8-one (C15H14O5) (1) and 7a, 11a-dihydro-7a, 11a-dimethyl-2H-pyrano[2′, 3′∶4, 5]benzofuro[3, 2-d](1, 3)dioxan-2-one (C15H14O5) (2) have been assigned by1H and13C NMR measurements, mass spectrometry results, and X-ray analysis. Compound (1): triclinic,P¯1,a=9.847(2),b=8.927(2),c=8.334(2) Å,α=95.98(2),β=108.81(3), γ=106.73(3)°; compound (2): triclinic,P¯1,a=7.296(4),b=7.481(2),c=11.812(4) Å,α=91.67(2),β=95.97(4), λ=94.20(3)°. The structures were solved by direct methods and refined by full-matrix least squares toR=0.050 (1) and 0.056 (2). In both compounds the coumarin rings can be regarded as coplanar, while the five-membered ring adopts an envelope conformation and the 1,3-dioxane ring a chair conformation.