Photochemistry of Coumarin-Based PhotoCORMs

                   Qiuyun Yang,^1^ Jiří Váňa,^2 Youhei Chitose,^1 Petr Klán^*,1

 ^1Department of Chemistry and RECETOX, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
                                   (e-mail: 477801@mail.muni.cz)

  ^2Institute of Organic Chemistry and Technology, Faculty of Chemical Technology, University of
                    Pardubice, Studentská 573, 53210 Pardubice, Czech Republic

Coumarins are a very large family of photoactive compounds. They are widely found in nature and
thousands of coumarin derivatives have been isolated or synthetized up to now. Coumarin moiety have
also been used as a part of biologically active compounds with various biological activities, such
as anticancer, antioxidant, antibacterial effects.^1 In addition, photochemical properties are also
promising; Coumarins have found extensive applications as optical bleaching agents, fluorescent
sensors, and photosensitisers.^2

 Recently, the therapeutic effects of CO in biological tissues have been extensively studied. The
light-triggered CO release as one of the most promising ways provides the high temporal and spatial
control of this process. Two promising photoCORMs based on xanthene and BODIPY (Figure 1: a, b,
respectively) and their proposed mechanism have been reported by our group in recent years.^3

To study the mechanism of CO release, we decided to use the coumarin moiety as a simplification of
a xanthene photoCORM structure and extensively studied the mechanism of CO release under different
conditions.

Herein, the coumarin 3-carboxylic acid (Figure 1: c, d) as potential photoCORM has been studied.
This study includes determination of CO release after irradiation at 355 nm in various solvents by
GC/MS headspace analysis, as well as analysis of photoproducts (HRMS, HPLC techniques). The
proposed mechanisms of photolysis will be discussed.

      Figure 1. Structure of photoCOMRs based on a) xanthene, b) BODIPY, c) coumarin-3-COOH.

1. (a) Duxia, C., et al. Chem. Rev. 2019, 119 (18), 10403-10519.

    (b) Yasameen, A., et al. Sys Rev Pharm. 2017, 8 (1), 24-30.

2. (a) Pereira, T. M., et al. Curr. Topics. Med. Chem. 2018, 18, 124-148.

    (b)Kasperkiewicz, K., et al. Lett. Drug. Des. Discovery 2016, 13, 465-474.

3. (a) Palao E., et al. J. Am. Chem. Soc. 2016, 138, 126-133.

    (b) Lovely Angel P. A., et al. Org. Lett. 2013, 15, 4552-4555.