51 X-ray structure analysis: Enraf-Nonius CAD-4 diffractometer. Unit cell parameters were determined from automatic centering of 25 reflections (12 < 28< 30") and refined by least-squares method. Intensities were collected with graphite monochromatized Mo,, (0.71069 A) radiation using the o scan technique. Lorentz polarization and extinction corrections were made. The structure was solved by direct methods and successive Fourier difference syntheses, using the SHELXL-93 computing program. C,H,N,,Mn, ( M = 436).The refinements by full matrix least-squares gave final Rl(F,) = 0 028, n.R2(F:) = 0.1356 and S = 0.78 1161 from 2432 reflections with intensity /22u(1) for 137 variables. All non-hydrogen atoms were refined anisotropically. The extreme nitrogen atom (N8) of one of the azido bridges is disordered. A strong pseudo-C symmetry is observed in the compound. Crystallographic data (excluding structure factors) for the structure(s) reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-179-81. Copies of the data can be obtained free ofcharge on application to The Director. CCDC, 12 Union Road, Cambridge CB2 IEZ. UK (fax: Int. code +(1223) 336-033; e-mail' teched (u chemcrys.cam.ac.uk) [16] Almost simultaneously to our paper,another papercontaining thesamecrystal structure was submitted by another research group (see preceeding communication).
A versatile statin side-chain building block is obtained by an enzymatic desymmetrisation of the symmetrical glutaric acid diethyl ester. The monoacid is produced in almost quantitative yield in the desired high optical purity. The monoacid is easily converted to the corresponding acid chloride, which is a key compound to be elaborated to some statin side-chain derivatives. The optically active C-5 chain is subsequently elongated by two carbon atoms and syn-reduced to the final diol fragment.
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