Title

Aromatic nitration with bismuth nitrate in ionic liquids and in molecular solvents: A comparative study of Bi(NO 3) 3·5H 2O/[bmim][PF 6] and Bi(NO 3) 3· 5H 2O/1,2-DCE systems

Document Type

Article

Publication Date

12-12-2012

Abstract

A suspension of bismuth nitrate pentahydrate (BN) in [bmim][PF 6] or [bmim][BF 4] imidazolium ionic liquid (IL) is an effective reagent for ring nitration of activated aromatics under mild conditions without the need for external promoters. Nitration can also be effected in 1,2-DCE, MeCN, or MeNO 2 without additives. Nitration of activated arenes (anisole, toluene, ethylbenzene, cumene, p-xylene, mesitylene, durene, and 1,3-dimethoxybenzene) is considerably faster (time to completion) in BN/[bmim][PF 6] relative to BN/1,2-DCE and there are also differences in isomer distributions (for anisole, toluene, and ethylbenzene). With introduction of strongly deactivating substituents (-CHO; -MeCO; -NO 2) the BN/IL system is no longer active but reactions still proceed with BN/1,2-DCE in reasonable yields. The ready availability and low cost of BN, simple operation, and absence of promoters, coupled to recycling and reuse of the IL, provide an attractive alternative to classical nitration methods for activated arenes. Switching from Bi(NO 3) 3·5H 2O/[bmim][PF 6] to Bi(NO 3) 3· 5H 2O/1,2-DCE increases the scope of the substrates that can be nitrated. © 2012 Elsevier Ltd. All rights reserved.

Publication Title

Tetrahedron Letters

Volume

53

Issue

50

First Page

6782

Last Page

6785

Digital Object Identifier (DOI)

10.1016/j.tetlet.2012.09.137

ISSN

00404039

E-ISSN

18733581

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