Abstract
Highly efficient synthesis of benzofused heteroaromatic compounds via aerobic oxidation catalyzed by cyanide anion has been developed. The Schiff bases derived from 2-aminophenol and aldehydes provided the corresponding benzoxazoles in high yields in the presence of a catalytic amount of cyanide in an open flask under ambient conditions without the use of any external metal co-oxidants and bases. Furthermore, we have developed a catalytic sequential one-step protocol for the synthesis of benzoxazoles by adding a catalytic amount of NaCN to Schiff bases generated in situ from 2-aminophenol and aldehydes without the isolation of imine intermediates. This one-pot protocol was further extended to the synthesis of benzothiazoles from 2-aminothiophenol and aldehydes. A variety of aldehydes could be applied to this sequential one-pot protocol and the desired benzofused azole products were obtained in high yields.
| Original language | English |
|---|---|
| Pages (from-to) | 6565-6573 |
| Number of pages | 9 |
| Journal | Tetrahedron |
| Volume | 69 |
| Issue number | 32 |
| DOIs | |
| Publication status | Published - 2013 Aug 12 |
Bibliographical note
Funding Information:This work was partly supported by the nuclear research and development program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology . We also thank Professors D.-C. Ha and K. Choi (Korea University, Seoul, Korea) for their helpful discussions.
Keywords
- Aerobic oxidation
- Benzothiazoles
- Benzoxazoles
- Cyanide
- One-pot reaction
ASJC Scopus subject areas
- Biochemistry
- Drug Discovery
- Organic Chemistry