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Synlett 2005(17): 2595-2598  
DOI: 10.1055/s-2005-917107
LETTER
© Georg Thieme Verlag Stuttgart · New York

Liquid-Phase Traceless Synthesis of 3,5-Disubstituted 1,2,4-Triazoles

Xi-Cun Wang*a, Jun-Ke Wanga,b, Dong-Qing Wub, Ying-Xiao Zongb
a Gansu Key Laboratory of Polymer Materials, Northwest Normal University, College of Chemistry and Chemical Engineering, Lanzhou 730070, P. R. of China
b Key Laboratory of Resources and Environment, Chemistry of West China, Department of Chemistry, Hexi University, Zhangye 734000, P. R. of China
Fax: +86(936)8284286; e-Mail: wangjk@hxu.edu.cn;
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Publication History

Received 25 July 2005
Publication Date:
05 October 2005 (online)

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Abstract

A liquid-phase traceless route to 3,5-disubstituted-1,2,4-triazoles has been developed, which allows for the incorporation of two elements of diversity. The heterocycle was constructed upon PEG6000 (soluble polymer) modified by 4-hydroxy-2-methoxybenzaldehyde, from which a traceless cleavage could be realized with TFA-CH2Cl2. This method provided a library of 3,5-disub­stituted-1,2,4-triazoles with high yields and purity.

Key words

soluble polymer - 1,2,4-triazoles - Lawesson’s reagent - cyclization reaction - traceless cleavage

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All the compounds were characterized and their structures were confirmed by spectrometric methods (1H NMR, IR and MS) and elemental analysis.
For compound 8e: 1H NMR (400 MHz, DMSO-d 6): δ = 3.86 (6 H, s), 7.04-7.06 (4 H, m), 7.93-7.96 (4 H, m). IR: 1575, 1680, 2866, 3148 cm-1. MS (EI): m/z = 281 [M+]. Anal. Calcd for C16H15N3O2: C, 68.31; H, 5.37; N, 14.94. Found: C, 68.39; H, 5.31; N, 14.90.
For compound 8i: 1H NMR (400 MHz, DMSO-d 6): δ = 3.86 (3 H, s), 7.03-7.08 (2 H, m), 7.44-7.52 (2 H, m), 7.57-7.79 (4 H, m). IR: 1570, 1694, 2891, 3133 cm-1. MS (EI): m/z = 285 [M+]. Anal. Calcd for C15H12ClN3O: C, 63.05; H, 4.23; N, 14.71. Found: C, 63.17; H, 4.24; N, 14.68.