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Synlett 2007(20): 3123-3126  
DOI: 10.1055/s-2007-990925
LETTER
© Georg Thieme Verlag Stuttgart · New York

One-Pot Synthesis of 2H-Chromene Derivatives from ortho-Naphthoquinones

Fernando de C. da Silvaa, Alessandra Jorqueiraa, R. M. Gouvêaa, Maria C. B. V. de Souzaa, R. Alan Howieb, James L. Wardella, Solange M. S. V. Wardellc, Vitor F. Ferreira*a
a Universidade Federal Fluminense, Instituto de Química, Departamento de Química Orgânica, 24020-150 Niterói, Rio de Janeiro, Brazil
b Department of Chemistry, University of Aberdeen, Old Aberdeen, AB24 3EU, Scotland, UK
c Complexo Tecnológico, Medicamentos Farmanguinhos, Av. Comandante Guaranys 447, Jacarepaguá, Rio de Janeiro, RJ, Brazil
e-Mail: cegvito@vm.uff.br;
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Publication History

Received 14 June 2007
Publication Date:
03 December 2007 (online)

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Abstract

A general one-pot synthesis for 2H-chromenes is reported from ortho-naphthoquinones and allyltriphenylphosphonium salts, [(RMeC=CHCH2)Ph3P]+Br-, in the presence of aqueous NaOH and chloroform at room temperature.

Key words

chromenes - Wittig reaction - one-pot cyclisation - naphthoquinones

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Data was obtained at 120 K with Mo KGk-α radiation by means of the Enraf Nonius KappaCCD area detector diffractometer of the EPSRC crystallographic service, based at the University of Southampton. Data collection was carried out under the control of the program COLLECT17a and data reduction and unit cell refinement were achieved with the COLLECT17a and DENZO programs.17b Correction for absorption, by comparison of the intensities of equivalent reflections, was applied using the program SADABS.17c The program ORTEP-3 for Windows17d was used in the preparation of Figure [3] and SHELXL-9717e and PLATON17f in the calculation of molecular geometry. The structure was solved by direct methods using SHELXS-9717g and fully refined by means of the program SHELXL-97.17e In the final stages of refinement, hydrogen atoms were introduced in calculated positions and refined with a riding model.

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Crystal data collected at 120 K, colourless crystal: 0.16 × 0.10 × 0.06 mm3. Formula: C20H22O2; M = 294.38; monoclinic, P21/c, a = 8.657(2) Å, b = 7.9525(17) Å, c = 23.385(6) Å, β = 92.815(9)°, Z = 4, V = 1608.0(7) Å3, 3696 independent reflections [R(int) = 0.1482], 1562 observed reflections [I >2s(I)]; parameters refined: 203; number of restraints: 0; R(F): 0.1839 (obs. data), Δρmax = 0.28 Å-3. CCDC deposition no: 292382.

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General Procedure for 2 H -Chromenes 7-10: A mixture of the naphthoquinone (0.02 mol), allyltriphenylphosphonium salt (0.04 mol), CHCl3 (15 mL) and aq 50% NaOH (15 mL, 0.19 mol) was vigorously stirred for 48 h at r.t. The organic phase was collected, washed with H2O (3 × 10 mL), dried over MgSO4 and the solvent was evaporated. Purification of the crude product was achieved by flash column chromatography using hexane-CH2Cl2 as eluent.
6-Methoxy-3,3-dimethyl-3 H -benzo[ f ]chromene (7a): IR (KBr): 2971, 2938, 1634, 1588, 1574, 1515, 1464, 1450, 1443, 1411, 1379, 1351, 1283, 1247, 1220, 1207, 1199, 1160, 1130, 1119, 1092, 996, 981, 885, 841, 755, 727, 694, 626 cm-1. 1H NMR (300 MHz, CDCl3): δ = 1.50 (s, 6 H, Me), 3.98 (s, 3 H, OMe), 5.58 (d, J = 9.8 Hz, 1 H, H-2), 6.48 (s, 1 H, H-5), 6.95 (d, J = 9.8 Hz, 1 H, H-1), 7.30 (ddd, J = 1.2, 6.8, 8.5 Hz, 1 H, H-8), 7.49 (ddd, J = 1.2, 6.8, 8.3 Hz, 1 H, H-9), 7.89 (ddd, J = 0.7, 1.2, 8.3 Hz, 1 H, H-7), 8.17 (ddd, J = 0.7, 1.2, 8.5 Hz, 1 H, H-10). 13C NMR (75.0 MHz, CDCl3): δ = 27.4 (Me), 27.4 (Me), 55.5 (OMe), 76.2 (C-3), 97.4 (C-5), 106.8 (C-10b), 118.1 (C-1), 120.9 (C-10), 121.3 (C-6a), 122.3 (C-7), 122.5 (C-8), 126.0 (C-2), 127.1 (C-9), 130.4 (C-10a), 151.6 (C-4a), 156.4 (C-6). EIMS: m/z (%) = 240 (22) [M+], 225 (100), 210 (15). HRMS: m/z calcd for C16H16O2: 240.1150; found: 240.1139.
2,2,6,6-Tetramethyl-3,4-dihydro-2 H ,6 H -1,5-dioxatri­-phenylene (8a): mp 89-90 °C. IR (KBr): 2975, 2934, 1637, 1578, 1510, 1465, 1453, 1428, 1418, 1396, 1383, 1369, 1360, 1325, 1289, 1253, 1237, 1220, 1195, 1159, 1137, 1119, 1003, 974, 881, 762, 732, 710, 691, 665, 646 cm-1. 1H NMR (300 MHz, CDCl3): δ = 1.41 (s, 6 H, Me), 1.47 (s, 6 H, Me), 1.86 (t, J = 6.8 Hz, 2 H, H-3), 2.77 (t, J = 6.8 Hz, 2 H, H-4), 5.54 (d, J = 10.0 Hz, 1 H, H-7), 6.95 (d, J = 10.0 Hz, 1 H, H-8), 7.27 (ddd, J = 1.2, 6.8, 8.3 Hz, 1 H, H-11), 7.41 (ddd, J = 1.2, 6.8, 8.3 Hz, 1 H, H-10), 7.85 (ddd, J = 0.5, 1.2, 8.3 Hz, 1 H, H-12), 8.14 (ddd, J = 0.5, 1.2, 8.3 Hz, 1 H, H-9). 13C NMR (75 MHz, CDCl3): δ = 19.9 (C-4), 29.3 (Me), 29.3 (Me), 78.6 (C-6), 34.7 (C-3), 77.1 (C-2), 78.6 (C-6), 106.6 (C-8a), 110.3 (C-4a), 121.2 (C-9), 123.3 (C-12), 123.6 (C-12a), 124.6 (C-11), 124.8 (C-8), 128.0 (C-7), 128.7 (C-10), 131.6 (C-8b), 152.5 (C-4b), 152.6 (C-13). EIMS: m/z (%) = 294 (44) [M+], 279 (77), 223 (100). HRMS: m/z calcd for C20H22O2: 294.1620; found: 294.1617.
5,6,7,8-Tetrachloro-2,2-dimethyl-2 H -chromene (10): yellow solid; mp 83-84 °C. IR (KBr): 2924, 2870, 2854, 1681, 1600, 1455, 1428, 1392, 1379, 1327, 1308, 1237, 1225, 1205, 1151, 1051, 1018, 996, 970, 924, 900, 834, 791, 663 cm-1. 1H NMR (300 MHz, CDCl3): δ = 1.87 (d, J = 1.5 Hz, 3 H, Me), 1.88 (d, J = 1.5 Hz, 3 H, Me), 5.55 (dsept, J = 1.5, 8.3 Hz, 1 H, H-2), 6.92 (d, J = 8.3 Hz, 1 H, H-1). 13C NMR (75 MHz, CDCl3): δ = 19.0 (Me), 26.4 (Me), 30.0 (C-3), 111.0 (C-1), 112.9 (C-5), 118.3 (C-2), 125.1 (C-8a), 126.0 (C-7), 128.0 (C-6), 144.9 (C-8), 146.7 (C-4a).