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bromide, slightly shorter time was required to complete the
intramolecular cyclization.
In conclusion, we found that the novel N-(4,5-dihydroox-
azol-2-yl)benzamide as N,O-bidentate ligands were efficient
ligands, and demonstrated an efficient intramolecular cycli-
zation of substituted 1-arylacyl-3-(2-bromophenyl)thiourea
using CuI/N-(4,5-dihydrooxazol-2-yl)benzamide. Gener-
ally, good to excellent yields of the desired products could
be successfully obtained. This method can provide more
diversiform N-benzothiazol-2-yl-amides under relative mild
condition avoiding the use of the toxic bromine. Further-
more, the procedure extends the scope of the carbon–
heteroatom forming by using the more cost effective
Cu-catalyzed process.
4. For reviews, see: (a) Muci, A. R.; Buchwald, S. L. Top. Curr. Chem.
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Acknowledgments
5. For selected references, see: (a) Zhang, H.; Cai, Q.; Ma, D. J. Org.
Chem. 2005, 70, 5164–5173; (b) Choudary, B. M.; Sridhar, C.;
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We gratefully acknowledge the financial support of the
863 High Technology Program, the Qing-Lan program of
Jiangsu Province, Kua-Shi-Ji program of Education Minis-
try of China (for Y.P.), the Talent Foundation of Jiangsu
Province (BK2006513), the Major State Basic Research
Development Program (Grant No. 2006CB806104), and
Twenty-one Century Talent Foundation of the Ministry
of Education.
6. (a) Joyce, L. L.; Evindar, G.; Batey, R. A. Chem. Commu. 2004, 446–
´
´
447; (b) Benedı, C.; Bravo, F.; Uriz, P.; Fernandez, E.; Claver, C.;
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Castillon, S. Tetrahedron Lett. 2003, 44, 6073–6077.
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3087–3092.
Supplementary data
8. (a) Jiang, J.; Duan, C.; Li, Y.; Bai, J.; Pan, Y. Anal. Sci. 2006, 20,
x119–x120; (b) Jiang, J.; Duan, C.; Bai, J.; Pan, Y. Anal. Sci. 2006, 20,
x153–x154.
Supplementary data associated with this article can be
9. The preparation of the ligands: To a mixture of thiourea (5.0 mmol),
TEA (0.5 mmol), and DCC (5 mmol) was added reagent grade
CH3CN (10 mL). The reaction mixture was refluxed for 5–8 h, and
subsequently diluted with EtOAc (20 mL) and washed with H2O
(2 · 20 mL) and brine (1 · 10 mL). The organic layer was dried over
MgSO4, the solvent removed in vacuo, and the crude product purified
using silica gel column chromatography. As for ligand F:12 Mp: 98–
100 ꢁC, 1H NMR (300 MHz, CDCl3): d 9.56 (s, 1H), 7.42–7.26 (m,
5H), 4.57 (t, 2H), 3.94 (t, 2H); Anal. Calcd for C10H10N2O2: C, 63.15;
H, 5.30; N, 14.73. Found: C, 63.41; H, 5.38; N, 14.57.
10. Evindar, G.; Batey, R. A. Org. Lett. 2003, 5, 133–136.
11. General procedure: A Schlenk tube was charged with 1-acyl-3-(2-
bromophenyl)thiourea (1 mmol), Cs2CO3 (2.0 mmol), CuI (0.05 mmol,
5 mol %) and ligand (0.1 mmol, 10 mol %), evacuated and backfilled
with N2. DMSO was added. The reaction mixture was heated at
60 ꢁC for 8–10 h. until the 1-arylacyl-3-(2-bromophenyl)thiourea
disappeared monitored by TLC. The mixture was diluted with EtOAc
(50 mL) and washed with H2O (2 · 30 mL) and brine (2 · 20 mL),
dried over Na2SO4, and concentrated in vacuo. The crude product was
purified by column chromatography on silica gel to provide the desired
product. Entry 1: 1H NMR (300 MHz, DMSO-d6): 12.89 (s, 1H); 8.20
(d, J = 8.4 Hz, 2H); 8.09 (s, 1H); 7.80 (m, 2H); 7.72–7.54 (m, 3H); 7.36
(m, 1H); 13C NMR: (75 MHz, DMSO-d6) 170.1, 162.3, 150.6, 135.4,
133.8, 132.6, 130.7, 129.3, 128.6, 125.4, 123.5, 122.7. Anal. Calcd for
C14H10N2OS: C, 66.12; H, 3.96; N, 11.02. Found: C, 66.37; H, 4.10; N,
10.82. Entry 8: 1H NMR (300 MHz, DMSO-d6): 8.60 (s, 1H); 8.38 (d,
J = 8.6 Hz, 1H); 8.29 (d, J = 8.6 Hz, 1H); 2.71 (s, 3H). 13C NMR:
(75 MHz, DMSO-d6) 201.2, 176.0, 155.8 154.5, 135.8. 126.0, 125.4
121.9, 116.3, 30.1. Anal. Calcd for C11H7F3N2O2S: C, 45.84; H, 2.45;
N, 9.72. Found: C, 46.04; H, 2.49; N, 9.43.
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