Publication

Regioselective Transition-Metal-Free Synthesis of Diverse Benzothiazoles by Thermally Induced Cyclization of ortho-Halobenzanilides

조회수 : 32 등록일 : 2017.09.19 00:00

저자 : Chi, DY (Chi, Dae Yoon)
출처 : CHEMISTRYSELECT
출판일 : 2017.08.22


Regioselective Transition-Metal-Free Synthesis of Diverse Benzothiazoles by Thermally Induced Cyclization of ortho-Halobenzanilides


Jang, KS (Jang, Keun Sam)1 ] Shin, DS (Shin, Dong Seok)2 ] Song, HR (Song, Ho Rim)2 ] Lee, BS (Lee, Byoung Se)3 ] Chi, DY (Chi, Dae Yoon)2 ]


[ 1 ] Chonnam Natl Univ, Med Sch & Hosp, Dept Nucl Med, 42 Jebong No, Donggu 501757, Gwangju, South Korea
[ 2 ] Sogang Univ, Dept Chem, 1 Shinsudong Mapogu, Seoul 121742, South Korea
[ 3 ] FutureChem Co Ltd, Res Inst Labeling, Seoul 04782, South Korea



The highly regioselective and efficient synthesis of diverse substituted-benzothiazoles, including heterocyclic units and amino groups, was achieved in moderate to high yields from ortho-bromothiobenzanilides, ortho-bromoarylthioureas, ortho-bromobenzanilides, and ortho-dibromobenzanilides, regardless of the electron density and substituted positions, via the prevalent carbon-sulfur bond formation by thermally induced intramolecular cyclization reaction without using any metal sources or other additives. Polysubstituted-benzothiazoles, particularly 2,4-, 2,6-disubstituted, and 2,4,6-trisubstituted benzothiazoles, could be efficiently synthesized by a facile cascade reaction from appropriate ortho-bromobenzanilides under general thiolation conditions. This benign reaction represents a straightforward and practical approach toward diverse substituted-benzothiazoles. In addition, the remaining bromine substituent of the resulting products was further utilized as a functional handle for the additional diversification and exploited as a complementary solution for the adjustment of harsh reaction condition. This methodology not only allows for the elaboration of benzothiazole molecules, but also provides a new valuable synthetic tool for a range of pharmaceutical applications.






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