Structure of a 2'-oxo-8.1'-neolignan

Δ 8 -1',2'-Dihydro-3,4,3',4'-bismethylenedioxy-2'-oxo-8.1-neolignan [6-allyl-6-(1,3-benzodioxol5-ylpropylene)-1,3-benzodioxol-5(6H)-one], C 20 H 20 O 5 , M r =340.38, orthorhombic, P2 1 2 1 2 1 , a=6.628 (4), b=12.604 (6), c=20.774 (11) A, V=1735 (3) A 3 , Z=4, D x =1.308 g cm -3 , λ(Mo Kα)=0.7107 A, μ=0.876, F(000)=720, T=295 K, R=0.032, wR=0.041 for 972 unique reflections. The analysis confirmed the structure of this new 2'-oxo8.1'-neolignan, originally proposed on the basis of NMR data, and established the relative stereochemistry