Formation of the Compounds with an Epoxychromene Framework: Role of the Methoxy Groups

Earlier, it was found that the reaction of para-mentha-6,8-diene-2,3-diol with 2,4,5-trimethoxy- benzaldehyde in the presence of Montmorillonite K 10 clay led to the formation of a compound with an unusual epoxychromene framework among other products. In the current work, systematic studies of the effect of the number and position of MeO groups in the aromatic ring of the aldehyde on the reaction route were performed to reveal the structural parameters, which favor the formation of compounds with an epoxychromene framework. Compounds with an epoxychromene framework were shown to be formed if the benzaldehyde contained MeO substituents in o- and p-position. The highest yield was achieved in the case of 2,4,5-trimethoxybenzaldehyde.