Zhang H, Su RC, Qin YL, Wang XJ, Chen D, Liu XR, Jiang YX, Zhao P. Regioselective synthesis of 3-nitroindoles under non-acidic and non-metallic conditions.
RSC Adv 2023;
13:26581-26586. [PMID:
37674482 PMCID:
PMC10478488 DOI:
10.1039/d3ra03193d]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 07/26/2023] [Indexed: 09/08/2023] Open
Abstract
An electrophilic substitution reaction, without acid and metal, of indole with ammonium tetramethylnitrate for accessing 3-nitroindole has been developed. In this protocol, trifluoroacetyl nitrate (CF3COONO2) was produced by metathesis of ammonium tetramethyl nitrate and trifluoroacetic anhydride at sub-room temperature. Trifluoroacetyl nitrate (CF3COONO2) is an electrophilic nitrating agent for a variety of indoles, aromatic and heterocyclic aromaticity. Meanwhile, this strategy could be applied to construct the skeleton structure of many kinds of bioactive molecules. Interestingly, 3-nitroindole can be further derivatived as a pyrrolo[2,3-b]indole.
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