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Synlett 2019; 30(03): 325-328
DOI: 10.1055/s-0037-1611975
DOI: 10.1055/s-0037-1611975
letter
An Improved Synthesis of Balsaminone A
The authors thank the Department of Chemistry, The University of West-Indies for grants received towards this work.Further Information
Publication History
Received: 01 November 2018
Accepted after revision: 11 December 2018
Publication Date:
10 January 2019 (online)
Abstract
A short and efficient synthesis of balsaminone A, a dinaphthofuran-1,4-dione, is described. The eight-step synthesis features two alternate pathways including a base-induced coupling reaction of 4-methoxy-1-naphthol and 2,3-dichloro-1,4-naphthoquinone, as well as a light-mediated cyclization of 1,1'-binaphthoquinone to afford the dinaphthofurandione core. Subsequent ortho formylation yielded a known precursor to balsaminone A, affording the natural product in 20–27% yield. This represents a moderate increase from the previous synthesis of 7.4% yield.
Key words
balsaminone A - Liebermann coupling - light-mediated cyclization - naphthofurandione - natural productsSupporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/s-0037-1611975.
- Supporting Information
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References
- 1 Kirilmis C, Koca M, Servi S, Gur S. Turk. J. Chem. 2009; 33: 375
- 2 Buchan R, Musgrave OC. J. Chem. Soc., Perkin Trans. 1 1980; 90
- 3 Liebermann C. Chem. Ber. 1899; 32: 916
- 4 Martínez A, Fernández M, Estévez JC, Estévez RJ, Castedo L. Tetrahedron 2005; 61: 1353
- 5 del Coral JM. M, Castro MA, Gordaliza M, Martín ML, Gamito AM, Cuevas C, San Feliciano A. Bioorg. Med. Chem. 2006; 14: 2816
- 6 Ishiguro K, Ohira Y, Oku H. J. Nat. Prod. 1998; 61: 1126
- 7 Pei H, Lei J, Qian SA. Journal of Chinese Medicinal Materials 2012; 35: 407
- 8 Padwal W, Lewis W, Moody CJ. J. Org. Chem. 2011; 76: 8082
- 9 Brimble MA, Bachu P, Sperry J. Synthesis 2007; 2887
- 10 Bhatkhande BS, Adhikari MV, Samant SD. Ultrason. Sonochem. 2002; 9: 31
- 11 Ogata T, Okamoto I, Kotani E, Tekeya T. Tetrahedron 2004; 60: 3941
- 12 Zhdankin V, Stang PJ. Chem. Rev. 2008; 108: 5299
- 13 Synthesis of Carbaldehyde 7 DMF (5 mL, 64.85 mmol) in acetonitrile (5 mL) was added dropwise to a solution of oxalyl chloride (5 mL, 58.24 mmol) in acetonitrile (5 mL). The mixture was stirred at –10 °C for 1 h, after which a solution of 5-hydroxy-dinaphthofuran-7,12-dione (9a) (100.6 mg, 0.320 mmol) in acetonitrile (5 mL) and DMF (2 mL) was added, followed by CuI (10 mg, 0.056 mmol). The reaction mixture was stirred to reach r.t. and then heated at reflux overnight. After cooling to r.t., the solvent was removed in vacuo. The remaining residue was dissolved in ethyl acetate (40 mL), washed with water (3 x 10 mL) and brine (2 x 20 mL), and dried with magnesium sulfate. Evaporation of the solvent yielded a brown orange solid (107 mg), which was purified by column chromatography (ethyl acetate/hexane). The desired product was obtained as a pale-orange solid (60.1 mg, 55% yield). Mp 295–298 °C (methylene chloride) (ref.[8]302 °C); IR: 3678, 1728, 1330 cm–1; 1H NMR (MeOH): δ = 14.44 (s, 1 H, H-C=O), 11.17 (s, 1 H, OH), 8.26 (m, 4 H, H-2,3,9,10), 7.43 (m, 4 H, H-1,4,8,11); 13C NMR (MeOH): δ = 108.1, 116.9, 121.4, 125.0, 125.9, 126.1, 126.8, 127.7, 128.5, 132.0, 132.1, 133.4, 134.4, 148.0, 153.6, 164.0, 174.4, 180.9, 198.9.