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Synlett 2009(15): 2465-2468  
DOI: 10.1055/s-0029-1217825
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Iodine-Mediated Guanidine Formation through Arylsulfonyl-Activated Thioureas

Cuiying Qina, Jizhen Li*a, Erkang Fan*b
a College of Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, P. R. of China
Fax: 0086(431)88499179; e-Mail: ljz@jlu.edu.cn;
b Biomolecular Structure Center, Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
Fax: +1(206)6857002; e-Mail: erkang@u.washington.edu;
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Publikationsverlauf

Received 27 April 2009
Publikationsdatum:
17. August 2009 (online)

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Abstract

Reaction of arylsulfonyl thioureas with amines to form guanidines can be efficiently promoted through the use of iodine, instead of conventional reagents such as the Mukaiyama reagent or EDC. The general scope and limitations of the reaction are probed.

Key words

iodine - guanidine - arylsulfonyl thiourea - desulfurizations - aminations

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[ N -(2,2,4,6,7-pentamethyldihydrobenzofuran-5-sulfonyl)- N ′-(2-ethoxycarbonylethyl)- N ′′-benzyl guanidine (5o): Iodine (0.0928 g, 0.35 mmol) was added to a solution of thiourea 3e (0.0495 g, 0.12 mmol) dissolved in THF (4 mL), followed by DIPEA (0.0491 g, 0.35 mmol). After 10 min, BnNH2 (0.0388 g, 0.35 mmol) was added to the mixture, and the reaction mixture was stirred overnight at room temperature. The residue obtained after evaporation of the solvent was separated by silica gel column (petroleum ether-EtOAc) to afford 5o as a white solid (0.0364 g, 63%). MS: m/z = 502.3 [M + H]+. ¹H NMR (300 MHz, CDCl3): δ = 1.20-1.25 (t, J = 7.2 Hz, 3 H), 1.47 (s, 6 H), 2.10 (s, 3 H), 2.46-2.48 (d, J = 5.7 Hz, 2 H), 2.50 (s, 3 H), 2.58 (s, 3 H), 2.95 (s, 2 H), 3.44-3.50 (m, 2 H), 4.03-4.10 (m, 2 H), 4.30-4.32 (m, 2 H), 7.18-7.20 (m, 2 H), 7.29-7.31 (m, 3 H). ¹³C NMR (75 MHz, CDCl3): δ = 12.4, 14.1, 17.9, 19.2, 21.0, 28.6, 33.9, 36.9, 43.2, 45.4, 60.9, 86.3, 117.3, 124.4, 127.1, 127.8, 127.8, 132.3, 133.2, 138.4, 154.7, 158.6, 172.7. Anal. Calcd for C26H35N3O5S: C, 62.25; H, 7.03; N, 8.38. Found: C, 62.14; H, 7.12; N, 8.57.