Research on new oxidation - reduction reactions using sulfur to synthesize heterocyclic compounds

23/05/2022

Benzazole is one of the important compounds, representing a group of heterocyclic compounds with many unique biological activities. 1,3-benzazole derivatives have been shown to have anti-cancer, bacterial and fungal activities. In recent years, research on new methods of synthesizing 1,3-benzazole derivatives has been conducted, and attracted the attention of many scientists around the world.

Examples of biologically active benzazole O/N/S heterocyclic compounds

Until now, most methods for synthesizing 1,3-benzazole are based on condensation oxidation using oxygen as an oxidizing agent and catalyzed with different metals. However, the use of oxygen as an oxidizing agent has some limitations such as the reaction is often poor selectivity, requires the presence of metal catalysts, sometimes expensive, and the purification of the catalytic product is complicated. Working with gaseous oxygen requires special reactors, especially at high temperatures and pressures.

Recently, sulfur is being studied and used extensively in condensation oxidation reactions.Using sulfur as a condensate oxidation reaction agent or catalyst has several advantages such as sulfur being a solid, non-hygroscopic, stable and non-toxic. Compared to oxygen, it is extremely easy to use the correct amount of sulfur in a reaction even at high temperatures. In addition, reactions with sulfur can be catalyzed with inexpensive and non-toxic metals such as iron and molybdenum.With the above advantages, sulfur chemistry is a suitable method for environmentally friendly, green chemistry approach.

Project "Research on new oxidation-reduction reactions using sulfur to synthesize heterocyclic compounds", code KHCBHH.01/18-20 under the Basic Science Development Program in the field of chemistry science, life science, earth science and marine science for the period 2017-2025, directed by Assoc. Prof. Dr. Ngo Quoc Anh, Institute of Chemistry, was accepted and classified as Excellent.

The project has successfully studied 4 new methods of synthesizing heterocyclic compounds using sulfur as follows:

- Process of synthesizing arylbenzoxazole derivatives, synthesized 21 arylbenzoxazole compounds from 2-Aminophenol and Aldehydes.

- Synthesis process 2-benzoylbenzoxazole, synthesized 35 2-benzoylbenzoxazole compounds from 2-Aminophenol and acetophenone

- Synthesis process of Thioamides and Bis-Aza-Heterocyclic, 48 thioamides and Bis-Aza-Heterocyclic compounds were synthesized from Methylhetarenes with amines by DMSO agent.

- Synthesis process of 2-Benzoylbenzoxazoles and 2-Quinolylbenzoxazoles, synthesized 43 compounds of 2-Benzoylbenzoxazoles and 2-Quinolylbenzoxazoles from o-Nitrophenol with Acetophenones and Methylquinolines.