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Synlett 2007(20): 3141-3144  
DOI: 10.1055/s-2007-990897
LETTER
© Georg Thieme Verlag Stuttgart · New York

An Unexpected Triethylbenzylammonium Chloride Catalyzed Ring Opening of 2-Pyrones in the Synthesis of 1-Arylbenzo[f]quinoline-2-carboxamide Derivatives in Aqueous Media

Xiang-Shan Wang*a,b, Mei-Mei Zhangb, Qing Lia, Chang-Sheng Yaoa, Shu-Jiang Tua,b
a School of Chemistry and Chemical Engineering, Xuzhou Normal University, Xuzhou, Jiangsu 221116, P. R. of China
e-Mail: xswang@xznu.edu.cn;
b The Key Laboratory of Biotechnology for Medical Plant, Xuzhou, Jiangsu 221116, P. R. of China
e-Mail: xswang1974@yahoo.com; Fax: +86(516)83500065;
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Publication History

Received 16 August 2007
Publication Date:
21 November 2007 (online)

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Abstract

Reaction of N-arylidenenaphthalen-2-amine and 4-hydroxy-6-methylpyran-2-one in aqueous media catalyzed by triethylbenzylammonium chloride (TEBAC) at 90 °C unexpectedly gave a pyrone ring-opening product 1-aryl-1,4-dihydro-3-[(E)-2-hydroxy­prop-1-enyl]-N-(naphthalene-2-yl)benzo[f]quinoline-2-carbox­amide. Modification of the reaction protocol resulted in a three-component reaction among N-arylidenenaphthalen-2-amine, 4-hydroxy-6-methylpyran-2-one and naphthalen-2-amine.

Key words

N-arylidenenaphthalen-2-amine - benzo[f]quinoline-2-carboxamide - aqueous media

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General Procedure for the Syntheses of 1-Aryl-1,4-dihydro-3-[( E )-2-hydroxyprop-1-enyl]- N -(naphthalene-2-yl)benzo[ f ]quinoline-2-carboxamide Derivatives: A 50-mL flask was charged with N-arylidenenaphthalen-2-amine (2.0 mmol), 4-hydroxy-6-methylpyran-2-one (2.0 mmol, 0.252 g), naphthalen-2-amine (2.0 mmol, 0.286 g), TEBAC (0.2 mmol, 0.046 g), and H2O (10 mL). The reaction mixture was stirred at 90 °C for 10-16 h; the solid was isolated by filtration. The filtrate together with TEBAC could be used directly for subsequent runs of the same reaction. The crude products were washed with H2O and purified by recrystallization from DMF and H2O, and then dried at 80 °C for several hours under vacuum to give compound 3. Selected data: 1,4-Dihydro-1-(3,4-dimethoxyphenyl)-3-[(E)-2-hydroxyprop-1-enyl)-N-(naphthalene-2-yl)benzo[f]quinoline-2-carboxamide (3a): mp 241-243 °C. 1H NMR (DMSO-d 6): δ = 2.13 (s, 3 H, Me), 3.66 (s, 3 H, MeO), 3.71 (s, 1 H, OH), 3.75 (s, 3 H, MeO), 5.34 (s, 1 H, CH), 5.61 (s, 1 H, CH), 6.36 (dd, J = 8.4 Hz, J′ = 2.0 Hz, 1 H, ArH), 6.75 (d, J = 8.4 Hz, 1 H, ArH), 7.02 (d, J = 2.0 Hz, 1 H, ArH), 7.25 (d, J = 8.8 Hz, 1 H, ArH), 7.31-7.36 (m, 2 H, ArH), 7.43-7.51 (m, 3 H, ArH), 7.70 (d, J = 2.0 Hz, 1 H, ArH), 7.82-7.89 (m, 6 H, ArH), 10.59 (s, 1 H, NH), 12.31 (s, 1 H, NH). 13C NMR (DMSO-d 6): δ = 20.5, 55.9, 56.0, 62.0, 95.2, 111.9, 112.4, 117.4, 117.6, 119.2, 121.5, 123.3, 123.4, 123.9, 124.3, 126.2, 127.2, 127.4, 127.9, 128.0, 128.9, 129.0, 129.3, 130.5, 131.2, 131.7, 133.6, 134.8, 135.7, 135.9, 148.1, 149.5, 162.4, 167.7, 190.3. HRMS (EI): m/z [M+] calcd for C35H30N2O4: 542.2206; found: 542.2220. IR (KBr): 3109, 3060, 3052, 2947, 2832, 1681, 1612, 1598, 1516, 1466, 1451, 1393, 1374, 1331, 1286, 1254, 1203, 1183, 1138, 1124, 1027, 845, 815, 789, 746 cm-1.