Subscribe to RSS
Please copy the URL and add it into your RSS Feed Reader.
https://www.thieme-connect.de/rss/thieme/en/10.1055-s-00000083.xml
Synlett 2021; 32(10): 999-1003
DOI: 10.1055/a-1467-5585
DOI: 10.1055/a-1467-5585
letter
Tetrabutylammonium Iodide (TBAI) Catalyzed Electrochemical C–H Bond Activation of 2-Arylated N-Methoxyamides for the Synthesis of Phenanthridinones
K.S. would like to thank the University Grants Commission of India (UGC) for providing a Senior Research Fellowship under the Basic Scientific Research (BSR) program vide No. [F.25-1/2014-15, F.7- 227/2009 dt. 16th Feb, 2015]
Abstract
An electrochemical method for the synthesis of phenanthridinones through constant-potential electrolysis (CPE) mediated by Bu4NI (TBAI) is reported. The protocol is metal and oxidant free, and proceeds with 100% current efficiency. TBAI plays a dual role as both a redox catalyst and a supporting electrolyte. The intramolecular C–H activation proceeds under mild reaction conditions and with a short reaction time through electrochemically generated amidyl radicals. The reaction has been scaled up to a gram level, showing its practicability, and the synthetic utility and applicability of the protocol have been demonstrated by a direct one-step synthesis of the bioactive compound phenaglaydon.
Key words
tetrabutylammonium iodide - phenanthridinones - amidyl radicals - electrochemistry - C–H bond activation - constant-potential electrolysisSupporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/a-1467-5585.
- Supporting Information
Publication History
Received: 31 January 2021
Accepted after revision: 25 March 2021
Accepted Manuscript online:
25 March 2021
Article published online:
08 April 2021
© 2021. Thieme. All rights reserved
Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany
-
References and Notes
- 1a Nishiyama Y, Fujii S, Makishima M, Hashimoto Y, Ishikawa M. Int. J. Mol. Sci. 2018; 19: 2090
- 1b Qin S.-Q, Li L.-C, Song J.-R, Li H.-Y, Li D.-P. Molecules 2019; 24: 437
- 1c Matveenko M, Banwell MG, Joffe M, Wan S, Fantino E. Chem. Biodivers. 2009; 6: 685
- 1d Holl V, Coelho D, Weltin D, Dufour P, Bischoff P. Anticancer Res. 2000; 20: 3233
- 2a Wang G.-W, Yuan T.-T, Li D.-D. Angew. Chem. Int. Ed. 2011; 50: 1380
- 2b Karthikeyan J, Cheng C.-H. Angew. Chem. Int. Ed. 2011; 50: 9880
- 2c Senthilkumar N, Parthasarathy K, Gandeepan P, Cheng C.-H. Chem. Asian J. 2013; 8: 2175
- 2d Yedage SL, Bhanage BM. J. Org. Chem. 2016; 81: 4103
- 2e Pimparkar S, Jeganmohan M. Chem. Commun. 2014; 50: 12116
- 2f Sivakumar G, Vijeta A, Jeganmohan M. Chem. Eur. J. 2016; 22: 5899
- 3 Karthikeyan J, Haridharan R, Cheng C.-H. Angew. Chem. Int. Ed. 2012; 51: 12343
- 4a Liang D, Yu W, Nguyen N, Deschamps JR, Imler GH, Li Y, MacKerell AD. Jr, Jiang C, Xue F. J. Org. Chem. 2017; 82: 3589
- 4b Liang D, Sersen D, Yang C, Deschamps JR, Imler GH, Jiang C, Xue F. Org. Biomol. Chem. 2017; 15: 4390
- 5 Moon Y, Jang E, Choi S, Hong S. Org. Lett. 2018; 20: 240
- 6a Kärkäs MD. Chem. Soc. Rev. 2018; 47: 5786
- 6b Liang S, Xu K, Zeng C.-C, Tian H.-Y, Sun B.-G. Adv. Synth. Catal. 2018; 360: 4266
- 6c Zhang P, Chen J, Gao W, Xiao Y, Liu C, Xu S, Yan X, Qin D. Molecules 2019; 24: 696
- 6d Liu K, Tang S, Wu T, Wang S, Zou M, Cong H, Lei A. Nat. Commun. 2019; 10: 639
- 7 Zhang S, Li L, Xue M, Zhang R, Xu K, Zeng C. Org. Lett. 2018; 20: 3443
- 8 Kehl A, Breising VM, Schollmeyer D, Waldvogel SR. Chem. Eur. J. 2018; 24: 17230
- 9a Wu X.-F, Gong J.-L, Qi X. Org. Biomol. Chem. 2014; 12: 5807
- 9b Uyanik M, Okamoto H, Yasui T, Ishihara K. Science 2010; 328: 1376
- 9c Finkbeiner P, Nachtsheim BJ. Synthesis 2013; 45: 979
- 9d Gao W.-J, Li W.-C, Zeng C.-C, Tian H.-Y, Hu L.-M, Little RD. J. Org. Chem. 2014; 79: 9613
- 9e Liang S, Zeng CC, Luo XG, Ren FZ, Tian HY, Sun BG, Little RD. Green Chem. 2016; 18: 2222
- 10a Bard AJ, Faulkner LR. Electrochemical Methods: Fundamentals and Applications, 2nd ed. Wiley; New York: 2001
- 10b Moeller KD. Tetrahedron 2000; 56: 9527
- 11 Tu Z, Chu W, Zhang J, Dence CS, Welch MJ, Mach RH. Nucl. Med. Biol. 2005; 32: 437
- 12 Syroeshkin MA, Krylov IB, Hughes AM, Alabugin IV, Nasybullina DV, Sharipov MY, Gultyai VP, Terent’ev AO. J. Phys. Org. Chem. 2017; 30: e3744
-
13
5-Methoxyphenanthridin-6(5H)-one2d (2a); Typical Procedure
A 25 mL pear-shaped three-necked undivided cell equipped with Pt plate anode (30 × 15 mm) and a Cu plate cathode (30 × 15 mm) was charged with a solution of N-methoxybiphenyl-2-carboxamide (1a; 0.5 mmol, 113.6 mg) and TBAI (0.1 mmol, 36.9 mg) in DMF (15 mL). The cell was then connected to a regulated DC power supply, and constant-potential electrolysis was carried at 2.5 V and 70 °C until 2 F mol–1 electric charge was consumed (~5 h). The mixture was constantly stirred during the electrolysis. The resulting mixture was diluted with EtOAc and washed twice with H2O. The organic layers were collected, dried (Na2SO4), filtered, and concentrated in vacuo. The crude product was purified by column chromatography [silica gel, PE–EtOAc (9.5:0.5)] to give a white solid; yield: 101.4 mg (90%); mp 102–104 °C.
1H NMR (400 MHz, CDCl3): δ = 8.57 (d, J = 8.1 Hz, 1 H), 8.28 (dd, J = 8.3, 4.0 Hz, 2 H), 7.79 (t, J = 7.8 Hz, 1 H), 7.69 (d, J = 8.3 Hz, 1 H), 7.60 (q, J = 7.9, 7.4 Hz, 2 H), 7.41–7.32 (m, 1 H), 4.14 (s, 3 H). 13C NMR (100 MHz, CDCl3): δ = 157.3, 135.8, 133.0, 132.6, 130.0, 128.5, 128.1, 126.3, 123.2, 121.9, 118.6, 112.6, 62.7. GC/MS (EI, 70 eV): m/z (%) = 225.0 (39.0), 195.0 (100), 180.0 (28.7), 166.05 (58.2), 152.05 (16.0), 140.05 (28.6), 83.4 (13.7), 76.0 (13.2), 40.0 (13.9).