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DOI: 10.1055/s-2007-985590
Novel Reaction of Indoles and Pyrrole with Pyrillium Catalyzed by Ceric Ammonium Nitrate (CAN)
Publication History
Publication Date:
14 August 2007 (online)
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Abstract
The reaction of xanthene derivatives with indoles and pyrrole catalyzed by CAN in methanol through SN1 reaction of pyrillium with a nucleophilic reagent afforded the corresponding indole- and pyrrole-substituted xanthene derivatives in high yields, respectively.
Key words
CAN - indole - pyrrole - xanthen - pyrillium
-
1a
Menchen SM,Benson SC,Lam JYL,Zhen W,Sun D,Rosenblum BB,Khan SH, andTaing M. inventors; US 6583168. -
1b
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1c
Reynolds GA,Tuccio SA,Peterson OG, andSpecht DP. inventors; DE 2109040. -
2a
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2b
Ravindranath B.Seshadri TR. Phytochemistry 1973, 12: 2781 -
2c
Gurudutt KN.Seshadri TR. Phytochemistry 1974, 13: 2845 -
2d
Kumar N.Seshadri TR. Curr. Sci. 1974, 43: 611 -
2e
Arnone A.Camarda L.Merlini L.Nasini G.Taylor DAH. J. Chem. Soc., Perkin Trans. 1 1977, 2116 - 3
Hideo T. inventors; Jpn. Tokkyo Koho JP 56005480. -
4a
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4b
Ion R.-M.Albulescu C.Sirkecioglu O.Talinli N. http://www.photobiology.com/photobiology2000/rodica2/index.htm, The Third Internet Photochemistry and Photobiology Conference, 2000, - 5
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Ji S.-J.Wang S.-Y. Synlett 2003, 2074 - In the last 20 years, reactions of xanthen-9-ol with indole, promoted by AcOH and BF3·OEt2, have been reported. See:
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References and Notes
Compound 1a with 3.0 equiv morpholine proceeded smoothly under sonic waves to give the 3′ after 3 h under neat conditions.
11
General Procedure for the Reaction of Indoles with 1-Oxo-13c-alkyloxy-1,13c-dihydro-dibenzo[
a
,
kl
]-xanthene
A mixture of 1-oxo-13c-methoxy-1,13c-dihydro-dibenzo[a,kl]-xanthene (1a, 0.157 g, 0.5 mmol), indole 2a (0.059 g, 0.5 mmol), CAN (0.014 g, 5 mol%), and anhyd MeOH (2 mL) was irradiated with ultrasound in an open vessel at r.t. until the indole was completely consumed (3 h, monitored by TLC). Then the reaction mixture was washed with cold H2O (3 × 15 mL) and cold EtOH (3 × 0.5 mL), respectively. The crude mixture was purified by flash chromatography to afford the pure product 4a (0.190 g, yield: 95%).
1-Oxo-13c-3-indoly-1,13c-dihydro-dibenzo[
a
,
kl
]-xanthene (
4a)
Kelly needles (chartreuse, acicular crystals) mp 192-194 °C. IR (KBr): ν = 3465, 3056, 1697 (C=O), 1458, 1227, 1026, 810, 740 cm-1. 1H NMR (400 MHz, CDCl3): δ = 6.43 (d, 1 H, J = 9.6 Hz), 6.84-6.88 (m, 2 H), 6.97-7.21 (m, 4 H), 7.78-7.81 (m, 7 H), 7.35-7.40 (m, 3 H), 7.65 (d, 1 H, J = 8.0 Hz), 7.75 (d, 1 H, J = 8.8 Hz), 7.89 (d, 1 H, J = 8.0 Hz), 8.08 (br, s, 1 H, NH). 13C NMR (100 MHz, DMSO-d
6): δ = 50.1, 111.8, 112.8, 115.8, 117.3, 117.4, 117.9, 118.8, 120.8, 122.2, 123.2, 123.6, 124.4, 124.5, 125.5, 127.4, 127.7, 128.0, 129.0, 130.6, 130.9, 132.3, 132.4, 135.3, 138.3, 147.6, 148.6, 201.0. HRMS: m/z calcd for C28H17NO2: 399.1259; found: 399.1240 [M+].
Crystallographic data for the structural analysis have been deposited with the Cambridge Crystallographic Data Centre, CCDC No. 268046 for compound 4e. Copies of this information may be obtained free of charge from The Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK [e-mail: linstead@ccdc.cam.ac.uk or deposit@ccdc.cam.ac.uk; fax: +44 (1223)336033]. Crystal data for 4e·C3H6O: C29H19NO2·C3H6O, Mr = 471.53, triclinic, space group P-1, a = 9.7116(16) Å, b = 10.9061(18) Å, c = 11.572(2) Å, α = 95.996(5)°, β = 101.305(5)°, γ = 96.887(5)°, V = 1182.8(4) Å3, Z = 2, Dcalc = 1.324 g cm-3, (MoKα) = 0.085 mm-1; 11701 reflections collected, 4286 unique reflections, R = 0.0196.
14
General Experimental Procedure
A mixture of indole 2a (0.059 g, 0.5 mmol), 7 (0.099 g, 0.5 mmol), CAN (0.014 g, 0.025 mmol), and anhyd MeOH (2 mL) was stirred in flask at r.t. until 2a was completely consumed (1 h, checked by TLC). After standing 0.5 h, the reaction mixture was washed with cold H2O (3 × 15 mL). The crude mixture was purified by flash chromatography to afford the pure product 3a (0.134 g, yield: 90%).
3-(9
H
-Xanthen-9-yl)-1
H
-indole (
8a)
Mp 143-145 °C (lit.
[13a]
145 °C). IR (KBr): ν = 3429 (NH), 3051, 2920, 2850, 1254, 749 cm-1. 1H NMR (400 MHz, CDCl3): δ = 5.55 (s, 1 H, CH), 6.90-7.36 (m, 13 H), 8.02 (br, s, 1 H, NH). 13C NMR (100 MHz, CDCl3): δ = 59.8, 111.2, 116.3, 119.6, 119.6, 120.3, 122.1, 122.8, 123.1, 124.4, 125.8, 127.7, 129.4, 136.7, 151.3. HRMS: m/z calcd for C21H15NO: 297.1154; found: 297.1157 [M+].