The crystal structure of the p-bromobenzoate of a dihydro-anhydro-acetonide derivative of taxa-4(16),11-diene-5α,9α,10β,13α-tetraol

Abstract

The crystal structure and absolute stereochemistry of the p-bromobenzoate of a dihydro-anhydro-acetonide derivative of taxadienetetraol, C₃₀H₃₉O₄Br, has been determined by the heavy-atom method from three-dimensional photographic data. This derivative is shown to contain a five-, a six-, and a seven-membered carbon ring in contrast to the two six- and one eight-membered rings of the parent tetraol. The crystals are orthorhombic with four molecules in a unit cell of dimensions a= 17·48, b= 20·62, and c= 7·76 Å. The space-group is P2₁2₁2₁. The structure has been refined by least-squares methods to a final residual (R) of 10·5% for 2723 hkl and hkl reflections. The molecular geometry is discussed.