Synlett 2015; 26(12): 1759-1763
DOI: 10.1055/s-0034-1380748
letter
© Georg Thieme Verlag Stuttgart · New York

Synthesis of 2-(Benzylthio)-4-(trifluoromethyl)thiazole-5-carboxylates Using S-Benzylisothiouronium Halides as Thiol Equivalents

Shane M. Hickey
a   Research Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, 3216, Australia   Email: t.ashton@deakin.edu.au
,
Jonathan M. White
b   Bio21 Institute, School of Chemistry, University of Melbourne, Parkville, Victoria, 3010, Australia
,
Frederick M. Pfeffer
a   Research Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, 3216, Australia   Email: t.ashton@deakin.edu.au
,
Trent D. Ashton*
a   Research Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, 3216, Australia   Email: t.ashton@deakin.edu.au
› Author Affiliations
Further Information

Publication History

Received: 26 March 2015

Accepted after revision: 17 April 2015

Publication Date:
21 May 2015 (online)


Abstract

S-Benzylisothiouronium halides are used as shelf-stable, odorless thiol equivalents. The method developed is used to access 2-(benzylthio)-4-(trifluoromethyl)thiazole carboxyl building blocks. Using the latent trifluoromethyl substituent the reactions could be monitored using 19F NMR spectroscopy.

Supporting Information

 
  • References and Notes

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  • 11 Example Procedure: Ethyl 2-[(4-Bromobenzyl)thio]-4-(trifluoromethyl)thiazole-5-carboxylate (12) A mixture of 2-bromothiazole 8 (152 mg, 0.50 mmol), Et3N (0.28 mL, 2.0 mmol, 4.0 equiv), and 6e (326 mg, 1.00 mmol, 2.0 equiv) in MeCN–PhCF3 (5 mL, Table 1) was heated at 120 °C for 60 min using MW irradiation. The reaction mixture was diluted using MeOH and concentrated onto SiO2 and then purified by column chromatography using CH2Cl2–petroleum spirits (1:3 to 1:1) to give 12 (178 mg, 84%) as a clear oil. 1H NMR (500 MHz, CDCl3): δ = 7.47–7.44 (m, 2 H), 7.31–7.28 (m, 2 H), 4.43 (s, 2 H), 4.35 (q, J = 7.1 Hz, 2 H), 1.36 (t, J = 7.1 Hz, 3 H). 13C NMR (125 MHz, CDCl3): δ = 169.2, 158.5, 145.7 (q, 2 J CF = 37.9 Hz), 134.6, 131.8, 130.9, 129.3, 122.0, 119.5 (q, 1 J CF = 271.1 Hz), 62.6, 37.2, 13.9. 19F NMR (470 MHz, CDCl3): δ = –61.93 (s). ESI-HRMS: m/z calcd for C14H11 79BrF3NO2S2 [M + H+]: 425.9439; found: 425.9446.