New aspects of the reactivity of allomaltol derivatives under UV irradiation have been discovered at the Zelinsky Institute

The study of various transformations of heterocyclic systems under UV irradiation is an important area of organic photochemistry. Among the wide variety of systems that are sensitive to UV light, derivatives of 3-hydroxypyran-4-one (allomaltol) attract special attention. It should be noted that the photochemical properties of this class of compounds have poorly been studied and are presented in the literature by only a few examples.

As part of the ongoing research by scientists from the Laboratory of Heterocyclic Compounds of the ZIOC devoted to the study of the photochemical properties of substituted derivatives of allomaltol, a method was developed for the synthesis of previously unknown 1H-cyclopenta[b]pyridine-2,7-diones. Propionic acid amides containing an allomaltol fragment were used as starting compounds in the considered photoreaction. The proposed approach is based on a cascade process, including the initial photoinduced contraction of the 4-pyranone ring with the formation of unstable α-hydroxy-1,2-diketone and subsequent intramolecular cyclization, leading to the target products. A distinctive feature of this approach is the use of the amide function of the side chain to trap the photogenerated unstable intermediate.

Source:

Constantine V. Milyutin, Renata D. Galimova, Andrey N. Komogortsev, Boris V. Lichitskii, Valeriya G. Melekhina, Vasily A. Migulin, Artem N. Fakhrutdinov, Mikhail E. Minyaev Photoinduced assembly of the 3,4,4a,7a-tetrahydro-1H-cyclopenta[b]pyridine-2,7-dione core on the basis of allomaltol derivatives Org. Biomol. Chem., 2021, 19, 9975-9985. DOI: 10.1039/D1OB01871J