1. School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K.
2. Chemical Development, Glaxo SmithKline Pharmaceuticals, The Old Powder Mills, Leigh, Tonbridge, Kent TN11 9AN, U.K.
3. Eli Lilly Research Centre, Erl Wood Manor, Sunninghill Road, Windlesham, Surrey GU20 6PH, U.K.