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Synlett 2005(18): 2747-2750  
DOI: 10.1055/s-2005-918951
LETTER
© Georg Thieme Verlag Stuttgart · New York

A Novel and Chemoselective Synthesis of 2-Aryloxazolines and Bis-oxazolines Catalyzed by Bi(III) Salts

Iraj Mohammadpoor-Baltork*a, Ahmad Reza Khosropour*b, Seyedeh Fatemeh Hojatia
a Department of Chemistry, Isfahan University, Isfahan 81746-73441, Iran
Fax: +98(311)6689732; e-Mail: imbaltork@sci.ui.ac.ir;
b Department of Chemistry, Razi University, Kermanshah 67149, Iran
Fax: +98(831)4274559; e-Mail: arkhosropour@razi.ac.ir;
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Publication History

Received 12 July 2005
Publication Date:
21 October 2005 (online)

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Abstract

Different arylnitriles react with β-aminoalcohols in the presence of catalytic amounts of Bi(III) salts such as Bi(TFA)3, Bi(OTf)3 and BiOClO4·xH2O producing the corresponding 2-aryl­oxazolines in high yields. Selective synthesis of mono- and bis-oxazolines from dicyanobenzenes and selective conversion of arylnitriles to their 2-oxazolines in the presence of alkylnitriles can be considered as noteworthy advantages of this method.

Key words

oxazolines - aminoalcohols - nitriles - bismuth(III) salts

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General Procedure.
To a mixture of arylnitrile (1 mmol) and β-aminoalcohol (4-8 mmol) was added the catalyst [0.25-0.33 mmol of Bi(TFA)3 and 0.05-0.066 mmol of Bi(OTf)3 or BiOClO4·xH2O]. The reaction mixture was stirred under reflux conditions for the appropriate time according to Table [1] . The progress of the reaction was monitored by TLC (n-hexane-EtOAc, 2:1). The reaction mixture was cooled to r.t. and the crude product was purified by column chromatography on neutral alumina to afford the pure product (Table [1] ).
Compound 2l: mp 98-100 °C. IR (KBr): 3040, 2900, 1647, 1490, 1230, 1056, 930, 670 cm-1. 1H NMR (500 MHz, CDCl3): δ = 4.09 (t, J = 9.6 Hz, 2 H), 4.46 (t, J = 9.6 Hz, 2 H), 7.53 (t, J = 7.8 Hz, 1 H), 7.74 (d, J = 7.7 Hz, 1 H), 8.18 (d, J = 7.8 Hz, 1 H), 8.22 (s, 1 H). Anal. Calcd for C10H8N2O: C, 69.76; H, 4.68; N, 16.27. Found: C, 69.80; H, 4.70; N, 16.15.