S-1 Synthesis and Biological Evaluation of  - Tubulin-binding Pironetin Analogues Lacking Alkyl Pendants in the Side Chain or the Pyrone Ring Julián Paños, † Santiago Díaz-Oltra, † María Sánchez-Peris, † Jorge García-Pla, † Juan Murga, † Eva Falomir, † Miguel Carda, † Mariano Redondo-Horcajo, § J. Fernando Díaz, § Isabel Barasoain § and J. Alberto Marco ‡ † Depart. de Q. Inorgánica y Orgánica, Univ. Jaume I, 12080 Castellón, Spain; § CIB, CSIC, 28040 Madrid, Spain; and ‡ Depart. de Q. Orgánica, Univ. de Valencia, 46100 Burjassot, Valencia, Spain Supporting Information Contents: S-2/S-4: Preparation and spectral data of some intermediate compounds used for stereochemical assigments S-5/S-34: NMR Spectra of compounds 1-6 and 9-12 Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry This journal is © The Royal Society of Chemistry 2013