Synthesis of a Heavy-Atom-Free BODIPY and its Photooxygenation of 1-Naphthol to 1,4-Naphthoquinone

Abstract

By using 1,5,6,7-dihydro-4H-indol-4-one, a carbonyl group was introduced onto a BODIPY photosensitizer. The resulting heavy-atom-free BODIPY is a highly effective producer of singlet oxygen with a calculated quantum yield (Φ_Δ) of 0.68, compared with that of methylene blue (Φ_Δ = 0.57). Photooxygenation of 1-naphthol to 1,4-naphthoquinone was achieved by using this heavy-atom-free BODIPY catalyst in the presence of white-light irradiation under air atmosphere. Our work demonstrated a practical example of the design of a heavy-atom-free BODIPY, capable of efficient singlet-oxygen generation, with a potential in photocatalysis.

Key words

BODIPY dyes - organophotocatalysis - difluoroboradiazaindacene - photooxygenation - photocatalysts

• References and Notes

• 1a Masson G, König B. Eur. J. Org. Chem. 2020; 1191
• 1b Marzo L, Pagire SK, Reiser O, König B. Angew. Chem. Int. Ed. 2018; 57: 10034
• 2 Pantaine L, Coeffard V, Moreau X, Greck C. Eur. J. Org. Chem. 2015; 2005
• 3a Rana P, Singh N, Majumdar P, Singh SP. Coord. Chem. Rev. 2022; 470: 214698
• 3b De Bonfils P, Péault L, Nun P, Coeffard V. Eur. J. Org. Chem. 2021; 1809
• 3c Chen K, Dong Y, Zhao X, Imran M, Tang G, Zhao J, Liu Q. Front. Chem. 2019; 7: 821
• 3d Zhang D, Liu G, Jiang X.-D. J. Mater. Chem. C 2023; 11: 1668
• 4a Cakmak Y, Kolemen S, Duman S, Dede Y, Dolen Y, Kilic B, Kostereli Z, Yildirim LT, Dogan AL, Guc D, Akkaya EU. Angew. Chem. Int. Ed. 2011; 50: 11937
• 4b Pang W, Zhang XF, Zhou J, Yu C, Hao E, Jiao L. Chem. Commun. 2012; 48: 5437
• 5a Wang X.-F, Yu S.-S, Wang C, Xue D, Xiao J. Org. Biomol. Chem. 2016; 14: 7028
• 5b Adarsh N, Shanmugasundaram M, Avirah RR, Ramaiah D. Chem. Eur. J. 2012; 18: 12655
• 5c Fischer J, Serier-Brault H, Nun P, Coeffard V. Synlett 2020; 31: 463
• 5d Yu Z, Wang H, Chen Z, Dong X, Zhao W, Shi Y, Zhu Q. J. Med. Chem. 2022; 65: 3616
• 5e Raza MK, Gautam S, Howlader P, Bhattacharyya A, Kondaiah P, Kondaiah AR. Inorg. Chem. 2018; 57: 14374
• 6a Dong Y, Dick B, Zhao J. Org. Lett. 2020; 22: 5535
• 6b Dong Y, Kumar P, Maity P, Kurganskii I, Li S, Elmali A, Zhao J, Escudero D, Wu H, Karatay A, Mohammed OF, Fedin M. Phys. Chem. Chem. Phys. 2021; 23: 8641
• 6c Nguyen VN, Yan Y, Zhao J, Yoon J. Acc. Chem. Res. 2021; 54: 207
• 7a Qi S, Kwon N, Yim Y, Nguyen V.-N, Yoon J. Chem. Sci. 2020; 11: 6479
• 7b Xi D, Xu N, Xia X, Shi C, Li X, Wang D, Long S, Fan J, Sun W, Peng X. Adv. Mater (Weinheim, Ger.) 2022; 34: 2106797
• 7c Zhang D, Peng L.-Y, Teng K.-X, Niu L.-Y, Cui G, Yang Q.-Z. ACS Mater. Lett. 2023; 5: 180
• 8a Yamamoto M, Shitomi K, Miyata S, Miyaji H, Aota H, Kawasaki H. J. Colloid Interface Sci. 2018; 510: 221
• 8b Okada A, Yuasa H, Fujiya A, Tada N, Miura T, Itoh A. Synlett 2015; 26: 1705
• 9 Carbonyl-BDP Under N₂, p-anisaldehyde (0.11 mL, 0.89 mmol) was added to 1,5,6,7-tetrahydro-4H-indol-4-one (300 mg, 2.21 mmol) in DCE (20 mL), and the mixture was stirred for 10 min. A drop of F₃CCO₂H was then added at rt, and the mixture was stirred at 70 °C for 2 h. DDQ (503.8 mg, 2.21 mmol) was added, and the resulting mixture was again stirred for 2 h at 70 °C. The mixture was then washed with H₂O (3 × 100 mL), and the aqueous solution was extracted with CH₂Cl₂ (2 × 50 mL). The organic layers were dried (MgSO₄), filtered, and concentrated. Et₃N (0.5 mL, 3.63 mmol) was added to the resulting mixture in DCE (40 mL), and the mixture was stirred for 10 min. BF₃·Et₂O (1.0 mL, 7.26 mmol) was then added, and the mixture was stirred for a further 2 h. The mixture was then washed with H₂O (3 × 100 mL), and the organic layers were dried (MgSO₄), filtered, and concentrated. The crude product was purified by column chromatography [silica gel, CH₂Cl₂–hexane (6∶1)] to give a dark-pink solid; yield: 15.6 mg (13%). ¹H NMR (400 MHz, CDCl₃): δ = 7.77 (s, 2 H), 7.57 (d, ³ J = 8.8 Hz, 2 H), 7.09 (t, ³ J =8.8 Hz, 2 H), 3.944 (s, 3 H), 3.31 (t, ³ J = 6.4 Hz, 4 H), 2.35 (t, ³ J = 7.6 Hz, 4 H), 2.21 (t, ³ J = 7.6 Hz, 4 H). ¹³C NMR (125 MHz, CDCl₃): δ = 183.8, 163.1, 137.5, 132.9, 130.1, 130.1, 129.8, 128.3, 114.7, 114.2, 55.5, 32.1, 27.3, 22.8. HRMS (ESI): m/z [M + H]⁺ calcd for C₂₄H₂₂BF₂N₂O₃: 435.16861; found: 435.16848.