Synthesis and new reactions of 3,6-diaminothieno[2,3-b]pyridine-5-carbonitriles

The chemistry of thieno[2,3-b]pyridine derivatives still remains a rapidly developing area of research, which has repeatedly become the subject of detailed consideration in a number of papers and reviews and dissertations. In recent years, significant progress has been made in this area of heterocyclic chemistry, which is reflected in a significant number of new publications concerning methods for the preparation, modification, and especially issues of biological activity of thieno[2,3-b]pyridine derivatives. It is important to note that thieno[2,3-b]pyridine derivatives are used in various fields , which confirms their importance and prospects for further research. In this regard, further study of these compounds plays an important role in the development of scientific knowledge and practical application in the modern world.

6-Aminopyridine-3,5-dicarbonitriles and 3,6-diamino-5-cyanothieno[2,3-b]pyridines are well known as compounds with a broad spectrum of bioactivity. In particular, such thienopyridines are known as inhibitors of scrapie prion infection replication and accumulation, as well as selective inhibitors of malaria plasmodia kinase-3 with a pronounced antimalarial effect.

To expand the range of such compounds, we studied the reaction of 3,6-diaminothieno[2,3-b]pyridine-5-carbonitriles with chloroacetyl chloride. The analysis of the Fukui indices showed that in these compounds the amino group at the C(3) atom is the most reactive. In fact, the reaction with ClCH2C(O)Cl leads to the predicted product. Other reactions of thienopyridines as well as data on the biological activity of the products are discussed.