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Kumar S, Fatma L, Vaishanv NK, Mohanan K. CsF-Mediated Reaction of Trifluorodiazoethane with 3-Nitroindoles Enables Access to Trifluoromethylpyrazolo[4,3- b]indoles. J Org Chem 2024; 89:761-769. [PMID: 38145929 DOI: 10.1021/acs.joc.3c02200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
A mild and metal-free strategy for the construction of trifluoromethylated pyrazolo[4,3-b]indoles through the reaction of N-substituted 3-nitroindoles with trifluorodiazoethane is reported. This operationally simple transformation involves a [3 + 2] cycloaddition of trifluorodiazoethane with 3-nitroindole, followed by the elimination of the nitro group to furnish pyrazole-fused indoles. The synthetic utility of this method is further demonstrated by applying it to other heterocycles, such as 3-nitrobenzothiophene and 2-nitrobenzofuran.
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Affiliation(s)
- Sandeep Kumar
- Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram Extension, Sitapur Road, P.O. Box 173, Lucknow 226031, India
| | - Lubina Fatma
- Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram Extension, Sitapur Road, P.O. Box 173, Lucknow 226031, India
| | - Narendra Kumar Vaishanv
- Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram Extension, Sitapur Road, P.O. Box 173, Lucknow 226031, India
| | - Kishor Mohanan
- Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram Extension, Sitapur Road, P.O. Box 173, Lucknow 226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
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