Synthesis of dibenzo[b,f]oxepine derivatives substituted in the aromatic ring

Stilbene derivatives are characterized by many beneficial biomedical properties. They show, inter alia, chemopreventive [28], anti-inflammatory and antioxidant properties [29]. One of the most popular stilbene derivatives are combretastatins, which can inhibit the polymerization process of microtubules [30]. Another stilbene derivative is, for instance, resveratrol, which is characterized by wide anti-cancer properties [31]. Dibenzo[b,f]oxepines also show advantageous and interesting biomedical properties. These compounds are stilbene analogs in which the two aromatic rings bond with each other with a vinyl bridge and an oxygen atom. Many dibenzo[b,f]oxepines have strong antipsychotic, anti-inflammatory, anti-depressant, insecticidal, anti-epileptic and anticancer properties [5]. Stilbenes and their precursors – oxepines, can be derived from azo compounds that are potential molecular photoswitches. These photoswitches are used in the socalled photopharmacology. The scope of photopharmacology is designing, synthesis, studying and using drugs, which activity can be controlled by light. The purpose of photopharmacology is also to solve the problem of off-target activity and severe side effects by establishing an external modality for controlling the action of the drug. The use of such drugs in treatment could prevent systemic and environmental side effects through the selective activation of them at the molecular target [1]. These molecular photoswitches based on oxepine ring could be extremely useful in photopharmacological therapy. The combination of azo group changing its configuration with the dibenzo[b,f]oxepine group should lead to the creation of interesting compounds. This is a promising combination of the medical properties of this bioactive compound with the function of the molecular photoswitch. A method of the synthesis of a series of azo dibenzo[b,f]oxepine derivatives was developed and implemented. Synthesized compounds can be used in the future as potential molecular photoswitches. For this purpose, a 4-step synthesis was conducted, starting from the simplest substrates – a benzaldehyde derivative and 2,4-dinitrotoluene (schem. 1).