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

Abstract

Earlier, it was found that the reaction of para‐mentha‐6,8‐diene‐2,3‐diol with 2,4,5‐trimethoxybenzaldehyde 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.

Prins cyclization: Synthesis of compounds with tetrahydropyran moiety over heterogeneous catalysts

“…It has been discovered that compounds with 6-membered oxygen-containing heterocycles with tetrahydropyran moiety are widely used for the synthesis of biologically active compounds with a potential for use in medicine [1]. These compounds can exhibit analgesic, anti-inflammatory or cytotoxic activity [1][2][3][4]. Synthesis of compounds with the desired tetrohydropyran structure can be realized by several important methods, including Prins cyclization onto oxocarbenium ions, oxy-Michael reactions, transition metal catalyzed cyclizations, reduction of cyclic hemi ketals and hetero-Diels-Alder cycloaddition [1].…”

A practical way to synthesize chiral fluoro-containing polyhydro-2H-chromenes from monoterpenoids

“…In addition to the expected products 2f and 8f , tricyclic compound 9f with an epoxychromene scaffold was isolated from the reaction mixture (Scheme 3), whose formation was previously observed only when using K10 clay [24]. …”

Catalytic synthesis of terpenoid-derived hexahydro-2H-chromenes with analgesic activity over halloysite nanotubes

“…Indeed, vicinal diols as well as allylic hydroxyls usually differ from aliphatic alcohols in chemical properties. Thus, it is not surprising that complex mixtures of products are often formed when the compound 1 reacts with aldehydes in the presence of K-10 clay significantly influencing resinification [41]. Usually, the reactions with diol 1 require longer time in comparison with isopulegol 6 and lead to lower yields of the desired products.…”