Synlett 2010(13): 1927-1930  
DOI: 10.1055/s-0030-1258490
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Expedient Synthesis of Highly Functionalized Coumarin Derivatives through a Domino Reaction

Subban Kathiravan, Raghavachary Raghunathan*
Department of Organic Chemistry, University of Madras, Guindy Campus, Chennai 600 025, India
Fax: +91(44)22352494; e-Mail: ragharaghunathan@yahoo.com;
Further Information

Publication History

Received 4 May 2010
Publication Date:
09 July 2010 (online)

Abstract

The straightforward synthesis of novel pentacyclic and hexacyclic coumarin heterocycles in a one-pot domino reaction is described. The process enables the synthesis of diversified coumarins in high yields in a single step.

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Synthesis of Polycyclic Coumarin Derivative 3a - Typical Procedure
To a refluxing solution of coumarin 2 (1 mmol) in anhyd DMF (5 mL), aldehyde 1a (1mmol), piperidine (5 mol%) were added, and the reaction mixture was refluxed for 4-5 h until the disappearance of starting material as evidenced by TLC. After completion of the reaction, H2O (5 mL) was added, and the reaction mixture was extracted with EtOAc
(3 × 15 mL), dried (Na2SO4), and the solvent was evaporated. The residue was subjected to column chromatography using hexane-EtOAc (95:5).
Compound 3a: R f = 0.5; white solid, mp 112-114 ˚C. IR (KBr): 1635 cm. ¹H NMR (300 MHz, CDCl3): δ = 3.52 (s, 3 H), 4.35 (d, J = 11.4 Hz, 1 H), 4.57 (d, J = 11.4 Hz, 1 H), 4.86 (s, 1 H), 5.62 (s, 1 H), 6.58-7.85 (m, 13 H). ¹³ NMR (75 MHz, CDCl3): δ = 36.68, 48.60, 52.85, 61.91, 81.89, 104.21, 114.81, 116.00, 116.47, 117.79, 120.00, 122.87, 123.92, 126.59, 127.90, 128.42, 128.97, 129.23, 132.24, 134.00, 134.47, 152.47, 152.94, 158.50, 161.15, 170.56. HRMS (EI): m/z = 441.1330 [M+].

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Crystallographic data of compound 3f in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplemental publication no. CCDC-768492. Copies of the data can be obtained, free of charge on application to CCDC, 12 Union Road, Cambridge CB2 IEZ, UK [fax: +44(1233)336033 or email: deposit@ccdc.cam.ac.uk].