1. AstraZeneca, Process R&D, Avlon/Charnwood, Avlon Works, Severn Road, Hallen, Bristol BS10 7ZE, U.K., GlaxoSmithKline, Synthetic Chemistry, Old Powder Mills, Tonbridge, Kent TN11 9AN, U.K., and Pfizer, Chemical R&D, PGR&D, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K.