X-RAY CRYSTALLOGRAPHIC DETERMINATION OF THE STRUCTURE AND CONFORMATION OF NEW METABOLITES FROM MICROBIAL HYDROXYLATION BY ABSIDIA-BLAKESLEEANA ATCC-10148

The crystal structure and conformation of 10R-hydroxy-1,4,4-trimethyltricyclo[5.4.0.0(3.5)]undec-7-en-9-one (II) and 10S-hydroxy-1,4,4-trimethyltricyclo[5.4.0.0(3.5)]undec-7-en-9-one (III) have been determined by X-ray diffraction. In both cases the crystals were monoclinic, P2(1), a = 12.907 (4), b = 7.484 (3), c = 14.179 (4) angstrom, beta = 110.65 (3)-degrees, Z = 4, (II); a = 16.351 (5), b = 7.468 (3), c = 20.917 (6) angstrom, beta = 91.83 (4)-degrees, Z = 8 (III). The structure was solved by direct methods, and refined to an R(w) value of 0.034 for 2483 (II) and 0.053 for 3810 (III) independent reflections, with I > 3.0-sigma(I). There were two crystallographically independent molecules in the case of II and four in the case of III. In all independent forms of both compounds the ring substituted by a carbonyl group had the distorted 3E sofa conformation; whereas the second one possessed the slightly deformed B-7,10 boat conformation. The crystal structures of II and III are stabilized by two and four intermolecular hydrogen bonds, respectively.