Abstract
Thionation of o-halobenzanilides was carried out in the presence of Lawesson’s reagent. Subsequently, the formed thioamides reacted with cesium carbonate to give the corresponding benzothiazole derivatives in the same pot.
Key words
one-pot reaction - benzothiazole - cesium carbonate - Lawesson’s reagent - cyclization
References and Notes
1 Current address (postdoctoral fellow): Service de Marquage Moléculaire et de Chimie Bioorganique, DSV/DBJC, CEA/Saclay, 91191 Gif-sur-Yvette, France; email: danbernardi@netcourrier.com, dan.bernardi@cea.fr.
2a
Bose DS.
Idrees M.
J. Org. Chem.
2006,
71:
8261
2b
Li Y.
Wang Y.
Wang J.
Chem. Lett.
2006,
35:
460
2c
Chakraborti AK.
Rudrawar S.
Kaur G.
Sharma L.
Synlett
2004,
1533 ; and references cited in these articles
3a
Ulrich H. In Science of Synthesis
Vol. 11:
Schaumann E.
Thieme;
Stuttgart:
2001.
p.835-912
3b
Chakraborti AK.
Selvam C.
Kaur G.
Bhagat S.
Synlett
2004,
851 ; and references cited in these articles
Sodium hydride:
4a
Spitulnik MJ.
Synthesis
1976,
730
4b
Mortimer CG.
Wells G.
Crochard J.
Stone EL.
Bradshaw TD.
Stevens MFG.
Westwell AD.
J. Med. Chem.
2006,
49:
179
4c
Van Zandt MC.
Jones ML.
Gunn DE.
Geraci LS.
Jones JH.
Sawicki DR.
Sredy J.
Jacot JL.
DiCioccio AT.
Petrova T.
Mitschler A.
Podjarny AD.
J. Med. Chem.
2005,
48:
3141
Sodium methoxide:
4d
Kim JS.
Sun Q.
Gatto B.
Yu C.
Liu A.
Liu LF.
LaVoie EJ.
Bioorg. Med. Chem.
1996,
4:
621
4e
Yoshino K.
Kohno T.
Uno T.
Morita T.
Tsukamoto G.
J. Med. Chem.
1986,
29:
820
4f Potassium carbonate: Hutchinson I.
Stevens MFG.
Westwell AD.
Tetrahedron Lett.
2000,
41:
425
5a
Lyon MA.
Lawrence S.
Williams DJ.
Jackson YA.
J. Chem. Soc., Perkin Trans. 1
1999,
437
5b
Downer NK.
Jackson YA.
Org. Biol. Chem.
2004,
2:
3039
6
Jesberger M.
Davis TP.
Barner L.
Synthesis
2003,
1929
7 Compounds 1, 4 and 5 were prepared according to literature procedure: Ilies MA.
Vullo D.
Pastorek J.
Scozzafava A.
Ilies M.
Caproiu MT.
Pastorekova S.
Supuran CT.
J. Med. Chem.
2003,
46:
2187
8 Compound 6 was prepared according to literature procedure: Shimada T.
Nakamura I.
Yamamoto Y.
J. Am. Chem. Soc.
2004,
126:
10546
9 Compound 7 was prepared according to literature procedure: Chen S.
Zhang X.
Ma H.
Lu Y.
Zhang Z.
Li H.
Lu Z.
Cui N.
Hu Y.
J. Organomet. Chem.
2005,
690:
4184
10 Compounds 8 and 9 were prepared according to literature procedure: Evindar G.
Batey RA.
J. Org. Chem.
2006,
71:
1802
11 Compound 10 was prepared according to literature procedure: Ganton MD.
Kerr MA.
Org. Lett.
2005,
7:
4777
12
Typical Procedure: In a 10-mL flask were placed the appropriate amide (1.17 mmol), Lawesson’s reagent13 (0.6 equiv, 0.29 g), xylene (3 mL) and a magnetic stirring bar. The mixture was stirred under argon at 105-115 °C for 2.5 h. Then Cs2CO3 (2 equiv, 0.81 g)was added and the reaction mixture was stirred under reflux for the indicated time. The solvent was evaporated to dryness and the crude product was chromatographed on silica gel (cyclohexane-EtOAc, 97:3) to afford the desired benzothiazole derivative.
13 During this study we used commercial and synthesized LR, prepared according to the literature procedure: Pedersen BS.
Scheibye S.
Nilsson NH.
Lawesson S.-O.
Bull. Soc. Chim. Belg.
1978,
87:
223
