1. Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, U.K., AstraZeneca Pharmaceuticals, Mereside, Alderley Park, Macclesfield, Cheshire, SK10 4TG, U.K., and AstraZeneca, Process R&D Avlon/Charnwood, Avlon Works, Severn Road, Hallen, Bristol, BS10 7ZE, U.K.