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Synfacts 2010(5): 0606-0606  
DOI: 10.1055/s-0029-1219734
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart ˙ New York

Solid-Phase Synthesis of Thiazolo[4,5-b]-pyridines

Contributor(s): Yasuhiro Uozumi, Yoichi M. A. Yamada, Hidetoshi Ohta
T. Lee*, D. Lee, I. Y. Lee, Y.-D. Gong
Korea Research Institute of Chemical Technology, Daejeon and Dongguk University, Seoul, Korea
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Publication History

Publication Date:
22 April 2010 (online)

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Significance

A solid-phase synthesis of 2,5,6,7-tetrasubstituted thiazolo[4,5-b]pyridines 9 using the Friedländer reaction as a key step is described. Thus, the known resin-bound cyano­carbonimidodithioate 2 was prepared from ­Merrifield resin with dipotassium cyanodithioimido-carbonate 1. The Thorpe-Ziegler cyclization of 2 with α-bromo ketones 3 gave the thiazole resins 4. The Friedländer reaction of 4 with ketones 5 was carried out in the presence of AlCl3 under microwave irradiation to give the resin-bound thiazolo[4,5-b]pyridines 6. The sulfide linkage of 6 was oxidized with MCPBA to give sulfone 7. Desulfo­native substitution of 7 with amines 8 afforded the corresponding products 9 (50 examples, 13-50% overall yield).