Methyl 6-[(3-hydroxy-5-isopropoxybenzoyl)amino]-3-pyridinecarboxylate (0.300 g, 0.91 mM), triphenylphosphine (0.238 g, 0.91 mM), iso-butanol (0.084 ml, 0.91 mM) and THF (8 ml) were combined and diisopropylazodicarboxylate (0.18 ml, 0.91 mM) was added dropwise. The mixture was stirred for 15 mins at ambient temperature. The reaction was concentrated under reduced pressure and the resulting brown oil was purified by column chromatography on Kieselgel 60, eluting with a gradient of 50–100% methylene chloride in iso-hexane and then 20% ethyl acetate in methylene chloride to give methyl 6-[(3-isobutoxy-5-isopropoxybenzoyl)amino]-3-pyridinecarboxylate as a colourless solid (0.232 g); [M+H]+ 387; [M−H]− 385.
