heptanal oxime

Purification Methods

Separate the cis(Z) and trans(E) oximes by liquid chromatography through a silica gel column and eluting with pet ether (b 40-65o)/EtOAc (50:10) at a flow rate of 2-3.4mL/sec where the trans-isomer comes through first and is a liquid with n D 1.38512 followed by the cis-isomer which is a solid and crystallises from 60% aqueous EtOH with m 55o. They are identified by TLC on 0.2mm silica gel G by eluting with *C6H6/EtOAc (50/10) and visualizing with I2 vapour: the trans-isomer has RF 0.6 and the cis-isomer has RF 0.5 [Pejkovic-Tadic et al. J Chromatography 21 239 1966, Emmous & Pagano J Am Chem Soc 77 4557 1955]. [Beilstein 1 H 698, 1 I 358, 1 II 752, 1 III 2850.]