Subscribe to RSS
DOI: 10.1055/s-2005-865194
An Efficient Synthesis of Bis(indolyl)methanes Catalyzed by Recycled Acidic Ionic Liquid
Publication History
Publication Date:
23 March 2005 (online)
Abstract
Green, mild and efficient electrophilic substitution reactions of indoles with various aldehydes were carried out using task-specific ionic liquids to afford the corresponding bis(indolyl)methanes in excellent yields.
Key words
acidic ionic liquids - indoles - carbonyl compounds - bis(indolyl)methanes
-
1a
Wasserschied P.Keim W. Angew. Chem. Int. Ed. 2000, 39: 3772 -
1b
Welton T. Chem. Rev. 1999, 99: 2071 -
2a
Cole AC.Jensen JL.Ntai I.Tran KLT.Weaver KJ.Forbes DC.Davis JH. J. Am. Chem. Soc. 2002, 124: 5962 -
2b
Sheldon R. Chem. Commun. 2001, 23: 2399 -
2c
Zhao G.-Y.Jiang T.Gao H.-X.Han B.-X.Huang J.Sun D.-H. Green Chem. 2004, 6: 75 -
3a
James H.Davis JH. Chem. Lett. 2004, 33: 1072 -
3b
Ishida Y.Sasaki D.Miyauchi M.Saigo K. Tetrahedron Lett. 2004, 45: 9455 -
3c
Wasserscheid P.Drießen-Hölscher B.Hal RV.Steffens HC.Zimmermann J. Chem. Commun. 2003, 16: 2038 -
3d
Dupont J.Spencer J. Angew. Chem. Int. Ed. 2004, 43: 5296 -
3e
Coleman KS.Turberville S.Pascu SI.Green MLH. Tetrahedron Lett. 2004, 45: 8695 -
4a
Porter JK.Bacon CW.Robins JD.Himmelsbach DS.Higman HC. J. Agric. Food Chem. 1977, 25: 88 -
4b
Osawa T.Namiki M. Tetrahedron Lett. 1983, 24: 4719 -
4c
Fahy E.Potts BCM.Faulkner DJ.Smith K. J. Nat. Prod. 1991, 54: 564 -
4d
Bifulco G.Bruno I.Riccio R.Lavayre J.Bourdy G. J. Nat. Prod. 1995, 58: 1254 -
4e
Bell R.Carmeli S.Sar N. J. Nat. Prod. 1994, 57: 1587 -
4f
Garbe TR.Kobayashi M.Shimizu N.Takesue N.Ozawa M.Yukawa H. J. Nat. Prod. 2000, 63: 596 -
5a
Roomi M.MacDonald S. Can. J. Chem. 1970, 48: 139 -
5b
Gregorovich B.Liang K.Clugston D.MacDonald S. Can. J. Chem. 1968, 46: 3291 -
6a
Woland W.Venkiteswaren M.Richards C. J. Org. Chem. 1961, 26: 4241 -
6b
Banerji J.Chatterjee A.Manna S.Pascard C.Prange T.Shoolery J. Heterocycles 1981, 15: 325 -
6c
Chatterjee A.Manna S.Banerji J.Pascard C.Prange T.Shoolery J. J. Chem. Soc., Perkin Trans. 1 1980, 553 -
6d
Babu G.Sridhar N.Perumal PT. Synth. Commun. 2000, 30: 1609 - 7
Kobayashi S.Araki M.Yasuda M. Tetrahedron Lett. 1995, 36: 5773 - 8
Yadav JS.Subba Reddy BV.Murthy CVSR.Kumar GM.Madan C. Synthesis 2001, 5: 783 - 9
Nagarajan R.Perumal PT. Tetrahedron 2002, 58: 1229 - 10
Bandgar BP.Shaikh KA. Tetrahedron Lett. 2003, 44: 1959 -
11a
Ji S.-J.Wang S.-Y.Zhang Y.Loh T.-P. Tetrahedron 2004, 60: 2051 -
11b
Ji S.-J.Zhou M.-F.Gu D.-G.Wang S.-Y.Loh T.-P. Synlett 2003, 13: 2077 -
11c
Ji S.-J.Zhou M.-F.Gu D.-G.Jiang Z.-Q.Loh T.-P. Eur. J. Org. Chem. 2004, 1584 - 12
Nagarajan R.Perumal PT. Chem. Lett. 2004, 33 (3): 288 -
13a
Li D.-M.Shi F.Peng J.-J.Guo S.Deng Y.-Q. J. Org. Chem. 2004, 69: 3582 -
13b
Li D.-M.Shi F.Guo S.Deng Y.-Q. Tetrahedron Lett. 2004, 45: 265 - 14
Fraga-Dubreuil J.Bourahla K.Rahmouni M.Bazureau J.-P.Hamelin J. Catal. Commun. 2002, 3: 185
References
Representative Experimental Procedure.
A mixture of indole (0.117 g, 0.50 mmol), 4-(benzo[d]ox-azol-2-yl)benzaldehyde (0.115 g, 0.25 mmol) and [hmim]HSO4 (0.0264g, 0.50 mmol × 5% mol) in EtOH (4.0 mL) was stirred at r.t. After completion of the reaction as indicated by TLC, the mixture was concentrated in vacuo to remove the solvent. The resulting solution was extracted with Et2O (5 × 10 mL). The organic layer was dried (Na2SO4), concentrated under vacuum and purified by column chromatography to afford the pure product.
3,3′-Bis-indolyl-4-(benzo[d]oxazol-2-yl)phenylmethane (2g): pale powder; mp 234-236 °C. IR (KBr): ν = 3421, 3053 cm-1. 1H NMR (400 MHz, CDCl3): δ = 5.99 (s, 1 H), 6.72 (s, 2 H), 7.03 (dd, J
1 = 7.6 Hz, J
2 = 7.2 Hz, 2 H), 7.19 (t, J = 7.2 Hz, 2 H), 7.35 (s, 2 H), 7.40 (dd, J
1 = 7.6 Hz, J
2 = 8.0 Hz, 4 H), 7.77 (s, 1 H), 8.02 (s, 2 H), 8.18 (d, J = 8.0 Hz, 2 H). HRMS: m/z calcd for C23H20N2S: [M] 439.1685; found: 439.1666 [M+].
3,3′-Bis-(5-methyl) indolyl-3-thienylmethane (3c): pink powder; mp 217-219 °C. IR (KBr): ν = 3410, 2909, 2848 cm-1. 1H NMR (400 MHz, CDCl3): δ = 2.38 (s, 6 H), 5.90 (s, 1 H), 6.69 (s, 2 H), 6.94 (s, 1 H), 7.00-7.06 (m, 4 H), 7.24 (d, J = 5.2 Hz, 4 H), 7.83 (s, 2 H). HRMS: m/z calcd for C23H20N2S: [M] 356.1347; found: 356.1334 [M+].