Synlett 2006(9): 1419-1421  
DOI: 10.1055/s-2006-939730
LETTER
© Georg Thieme Verlag Stuttgart · New York

Synthesis and Spectroscopic Properties of a Novel Bis-spirocalixarene

Michael Mastalerz, Gerald Dyker*
Fakultät für Chemie, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
e-Mail: gerald.dyker@ruhr-uni-bochum.de;
Further Information

Publication History

Received 15 February 2006
Publication Date:
22 May 2006 (online)

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Abstract

A convenient synthesis of the first spiro-bound calix[4]arene containing fluorenyl moieties at the para-position is presented. Dynamic NMR effects of the spiro-calixarene 4 are in ­accord with a preferred partial-cone conformation.

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Calixarene 2: To a solution of calixarene 1 (300 mg, 0.52 mmol) in 2-butanone (20 mL) NBS (1.135 g, 6.34 mmol) was added and the mixture was stirred for 20 h at r.t. An aq solution of Na2S2O3 (20%, 20 mL) was added and the mix-ture was stirred for 20 min before the layers were separated. The organic layer was washed with H2O (2 × 25 mL) and brine (25 mL), then dried over MgSO4. The solvents were removed on a rotary evaporator to give 430 mg of an orange colored residue. After flash chromatography (PE-EtOAc, 2:1; R f 0.26) and subsequent drying in vacuo (100 °C, 1 mbar), calixarene 2 was isolated as a colorless solid; yield: 230 mg (60%).
Mp 174 °C. IR (KBr): 3448, 3059, 2929, 1594, 1573, 1469, 1456, 1428, 1285, 1264, 1236, 1189, 1141, 1098, 1071, 990, 962, 914, 880, 858, 805, 776, 735 cm-1. 1H NMR (400.1 MHz, CDCl3): δ = 3.39 (d, J = 14.0 Hz, 4 H), 3.96 (d, J = 13.5 Hz, 4 H), 6.95 (t, J = 7.5 Hz, 2 H), 7.01 (d, J = 7.0 Hz, 4 H), 7.09 (m, 4 H), 7.14 (s, 4 H), 7.85 (t, J = 6.8 Hz, 2 H, Py-4-H), 8.25 (d, J = 3.5 Hz, 2 H, Py-6-H). 13C NMR (100.6 MHz, CDCl3): δ = 32.24 (t), 110.67 (d), 111.14 (s), 118.71 (d), 126.54 (d), 129.49 (d), 130.13 (d), 131.18 (s), 132.77 (s), 140.03 (d, Py-C-4), 147.32 (s), 147.81 (d, Py-C-6), 152.12 (s), 162.92 (s, Py-C-2). MS (FAB): m/z (%) = 737 (26)[M + H+]. UV/Vis (CH3CN): λmax (log ε) = 218 (4.6), 268 (3.9), 290 (sh, 3.7) nm. Anal. Calcd for C38H28Br2N2O4·H2O (754.48): C, 60.49; H, 4.01; N, 3.71. Found: C, 60.76; H, 3.79; N, 3.60.

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Calixarene 3: To a solution of bromocalixarene 2 (220 mg, 0.30 mmol) and 2-biphenylboronic acid (225 mg, 1.136 mmol) in THF (10 mL) an aq solution of K2CO3 (2 N, 10 mL) and Pd(PPh3)4 (115 mg, 99 µmol) were added and the mixture was stirred at 120 °C under argon in a screw-capped flask for 20 h. The organic layer was washed with brine (25 mL) and dried over MgSO4. THF was removed on a rotary evaporator to give 500 mg of a brown solid. After flash-chromatography (PE-EtOAc, 4:1; R f 0.16) and subsequent drying in vacuo, calixarene 3 was isolated as a colorless solid; yield: 120 mg (46%).
Mp 145-160 °C. IR (KBr): 3448, 3050, 2925, 1593, 1468, 1457, 1428, 1320, 1280, 1237, 1183, 1142, 1083, 919, 876, 804, 762, 747, 701 cm-1. 1H NMR (400.1 MHz, CDCl3): δ = 3.15 (d, J = 13.9 Hz, 4 H), 3.97 (d, J = 13.9 Hz, 4 H), 6.51 (d, J = 7.6 Hz, 4 H), 6.71 (s, 2 H), 6.77 (t, J = 7.6 Hz, 2 H), 6.86, (s, 4 H), 7.00 (ddd, 3 J = 7.0 Hz, 3 J = 5.0 Hz, 4 J = 0.8 Hz, 2 H, Py-5-H), 7.13 (d, J = 8.0 Hz, 2 H, Py-3-H), 7.15-7.23 (m, 10 H, biphenyl-H), 7.36-7.45 (m, 8 H, biphenyl-H), 7.74 (‘t’, J = 8.0 Hz, 2 H, Py-4-H), 8.19 (dd, J = 5.0 Hz, J = 1.8 Hz, 2 H, Py-6-H). 13C NMR (100.6 MHz, CDCl3): δ = 31.59 (t), 110.41 (d, Py-C-3), 118.55 (d, Py-C-5), 126.08 (d), 126.12 (d), 126.98 (d), 127.40 (s), 127.91 (s), 128.00 (d), 129.12 (d), 129.89 (d), 130.38 (d), 130.42 (d), 130.63 (d), 132.55 (s), 132.84 (s), 139.75 (d, Py-C-4), 140.48, 140.53, 142.04 (s), 146.65 (s), 148.06 (d, Py-C-6), 151.81 (s), 163.62 (s, Py-C-2). MS (FAB): m/z (%) = 883.3 (100) [M + H+]. UV/Vis (CH3CN): λmax (log ε) = 224 (5.1), 238 (sh, 5.0), 268 (4.8), 284 (sh, 4.6) nm. Anal. Calcd for C62H46N2O4·H2O (900.46): C, 82.63; H, 5.37; N, 3.11. Found: C, 82.52; H, 5.05; N, 2.79.

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To a degassed solution of calixarene 3 (96 mg, 0.11 mmol) in anhyd CH2Cl2 (50 mL) a solution of FeCl3 (465 mg, 2.87 mmol) in anhyd nitromethane (10 mL) was added dropwise over 5 min. A permanent stream of argon was bubbled through the solution. The reaction mixture was stirred for 40 min at r.t., MeOH (25 mL) was added and the volume of the solution was reduced to ca.10 mL. H2O (25 mL) was added and the resulting precipitate was collected and washed with H2O (3 × 10 mL). Flash chromatography (PE-EtOAc, 3:1; R f 0.36) and recrystallization (CH2Cl2-i-PrOH) gave 60 mg (68%) of the spiro compound 4 as colorless needles.
Mp 253-255 °C. IR (KBr): 3060, 2923, 2854, 1667, 1647, 1597, 1585, 1570, 1470, 1458, 1428, 1395, 1355, 1287, 1271, 1250, 1191, 1142, 1096, 1081, 988, 940, 917, 885, 865, 801, 778, 759, 733, 645, 619 cm-1. 1H NMR (400.1 MHz, CDCl3, 223 K): δ = 2.63 (d, J = 13.6 Hz, 2 H), 2.97 (d, J = 13.1 Hz, 2 H), 3.70 (d, J = 12.9 Hz, 2 H), 3.91 (d, J = 13.2 Hz, 2 H), 6.01 (d, J = 8.4 Hz, 2 H, Py-3-H), 6.30 (s, 2 H), 6.34 (s, 2 H), 6.71 (t, J = 5.5 Hz, 2 H, Py-4-H), 6.81 (d, J = 7.3 Hz, 2 H), 6.94 (t, J = 7.6 Hz, 2 H), 7.25 (t, J = 7.1 Hz, 3 H), 7.31 (m, 6 H), 7.39 (m, 1 H, Ar′H), 7.44 (m, 2 H), 7.57 (m, 2 H), 7.68 (t, J = 7.3 Hz, 1 H), 7.74 (t, J = 7.3 Hz, 1 H), 7.82 (d, J = 7.6 Hz, 1 H), 7.91 (m, 4 H), 7.98 (d, J = 7.3 Hz, 1 H), 9.18 (d, J = 7.6 Hz, 1 H). 13C NMR (100.6 MHz, CDCl3, 223 K): δ = 29.70 (t), 35.07 (t), 56.00 (s, spiro-C), 56.67 (s, spiro-C), 110.57 (d, Py-C-3), 116.92 (d, Py-C-4), 119.99 (d), 120.44, 120.63, 120.83, 124.25 (d), 124.46 (d), 124.72 (s), 124.93 (d), 127.09 (d), 127.54 (d), 127.81 (d), 128.39 (d), 128.48 (s), 128.69 (s), 129.45 (s), 130.64 (d), 130.72 (s), 131.79 (s), 136.78 (s), 139.21 (d, Py-C-3), 140.10 (s), 140.48 (s), 140.98 (s), 141.20 (s), 141.71 (d), 141.99 (s), 143.45 (s), 143.95 (d), 144.67 (s), 147.27 (Py-C-6), 149.28 (s), 163.10 (s, Py-C-1), 183.23, 185.93 (s). MS (FAB): m/z (%) = 901.4 (20)[M + Na+]. UV/Vis (CH3CN): λmax (log ε) = 227 (4.9), 258 (4.6), 291 (4.0), 302 (4.1) nm. Anal. Calcd for C62H42N2O4·0.5H2O (888.02): C, 83.86; H, 4.88; N, 3.15. Found: C, 83.64; H, 4.14; N, 2.96.