Structure of a Chiral Cyelopentanone Precursor in Neocarzinostatin Synthetic Studies, C20H21NO3S.H20

Abstract

(1E,2S,3R)-2-[(4R,5R)-4,5-Dimethyl-l,3-dioxolan-2-yl]-3-(2-naphthylthio)cyclopentanone oxime, 3//,=373.47, orthorhombic, P212121, a = 5-374 (13), b = 18.135 (3), c= 20.487 (5) A, V = 1997 (5)/~3, Z = 4, Dx = 1.24 g cm -3, Mo Ka, a = 0.71073/~, /z = 1-87 cm-1, F(000) = 792, room temperature, crystal volume 2.7 x 10 -4 mm 3, final R = 0.127 for 971 reflections with Fo2>0 out of 1131 data, R = 0.065 for 467 reflections with Fo 2 > 3o'(Fo2). Despite the small crystal size (all larger crystals were twinned), a structural solution of adequate precision was obtained. Bond distances and angles in the molecule are normal; the water molecules are hydrogen bonded in a chain along the a axis and each accepts a hydrogen bond from the oxime group and donates a weak hydrogen bond to 03 in the dioxolane group.