Abstract1Pentadecanoic, heptadecanoic and nonadecanoic acid were prepared from respectively myristic, palmitic, and stearic acid by the Arndt‐Eistert synthesis. The use of the Wilds and Meader variation for the rearrangement of the alkyldiazoketones, involving heating at 180° C with octanol‐2 or benzyl alcohol and γ‐collidine, gave fairly pure fatty acids. The reaction proceeded fast, and good yields were obtained. The advantage over the conventional Ag2O‐methanol method was especially marked in the case of nonadecanoic acid.2A chromatographic procedure, using silicagel as an adsorbent, petroleum ether as a solvent, and petroleum ether plus 25% ether as an eluent, was developed. This allowed a further purification of the products to pure fa