Synlett 2006(13): 2027-2030  
DOI: 10.1055/s-2006-948199
LETTER
© Georg Thieme Verlag Stuttgart · New York

1,3,5-Tris(2′-aminophenyl)benzene: A Novel Platform for Molecular Receptors

Piotr Piątek*, Norbert Słomiany
Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
Fax: +48(22)8225996; e-Mail: ppiatek@chem.uw.edu.pl;
Further Information

Publication History

Received 24 May 2006
Publication Date:
09 August 2006 (online)

Abstract

The synthesis of a novel, rigid, aromatic platform for molecular receptors is described. 1,3,5-Tris(2′-aminophenyl)benzene was prepared via Suzuki-Miyaura cross-coupling reactions of 2-aminophenylboronic acid with 1,3,5-triiodobenzene in the ­presence of Ba(OH)2, Pd(OAc)2 and (2-biphenyl)dicyclohexyl­phosphine. Alternatively, one-pot borylation of 2-bromoaniline and cross-coupling of the resulting boronate ester with 1,3,5-triiodo­benzene was investigated.

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Experimental Procedure (Table 1, Entry 4) and Spectroscopic Data for 1.
An oven-dried resealable Schlenk tube containing a magnetic stir bar was charged with 6 (1 mmol), 3 (0.3 mmol), Pd(OAc)2 (3 mol%), 7 (9 mol%) and Ba(OH)·8H2O (6 mmol). The Schlenk tube was capped with a rubber septum and then evacuated and backfilled with argon. Dry dioxane was added and the resulting mixture was heated at 85 °C with vigorous stirring for 24 h. The reaction mixture was then allowed to cool to r.t., filtered though a pad of Celite® and concentrated under reduced pressure. The crude material obtained was purified by flash chromatography on silica (MeOH-CH2Cl2, 2:98) to afford 1 as colorless solid. R f = 0.42 (MeOH-CH2Cl2, 3:97); mp 221-223 °C (toluene). 1H NMR (200 MHz, CDCl3): δ = 7.58 (s, 3 H), 7.24-7.12 (m, 6 H), 6.87-6.76 (m, 6 H), 3.72 (br s, 6 H). 13C NMR (50 MHz, CDCl3): δ = 143.5, 140.7, 130.5, 128.7, 128.2, 126.9, 118.8, 115.8. HRMS (ESI): m/z calcd for C24H21N3Na: 374.1633; found: 374.1640 [M + Na]+.