Dimethoxy aromatic compounds. IV.—determination of stereochemistry of 2,3,6,7‐tetraalkoxy‐9,10‐dihalomethyl‐9,10‐dihydroanthracenes by 13C NMR chemical shifts

The analysis of the 13C NMR spectra of several 2,3,6,7‐tetraalkoxy‐9,10‐dihalomethyl‐9,10‐dihydroanthracenes showed a strong dependence of the chemical shift values on the orientation of the halomethyl groups. On this basis it was possible to determine both the configuration (cis or trans) and conformation of the isomers, even if only one isomer was available.