The molecular structures of two furanoheliangolides

Abstract

The heliangolide-class sesquiterpene lactone 8β-angeloyloxy-9α-acetoxycalyculatolide, C₂₂H₂₆O₈,1, crystallizes in orthorhombic space groupP2₁2₁2₁ witha=12.455(3),b=12.601(3),c=14.023(5) Å,V=2200(1)Å,³ Z=4.R=0.059 for 1735 observed data. The 11,13-dihydro-11α, 13-epoxyatripliciolide-8β-angelate, C₂₀H₂₂O₇. 1/2 H₂O,2, crystallizes as the hemihydrate with two molecules in the asymmetric unit in triclinic space groupP1 witha=9.422(1),b=9.559(1),c=12.358(3) Å, α=101.62(2)°, β=91.30(2)°, γ=117.80(1)°,V=955.6(7)ų,Z=2.R=0.046 for 3607 observed data. In both, the 10-membered rings adopt approximate chair-boat conformations. Their conformations are typical for heliangolides. The methyl group C14 is α, while the C-15 has a β-orientation. The α-methylene-γ-lactone istrans-fused at C6 and C7 with H6 β and H7 α. In compound2, the epoxide at C11–C13 has an α orientation.