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Synfacts 2013; 9(1): 0113
DOI: 10.1055/s-0032-1317917
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart · New York

Annulation Reactions Catalyzed by Amberlite-Bound Hexafluorophosphate

Contributor(s):
Yasuhiro Uozumi
,
Makoto Nagaosa
Ghosh P, * Mandal A. University of North Bengal, Darjeeling, India
Synthesis of Functionalized Benzimidazoles and Quinoxalines Catalyzed by Sodium Hexafluorophosphate Bound Amberlite Resin in Aqueous Medium.

Tetrahedron Lett. 2012;
53: 6483-6488
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Publication History

Publication Date:
17 December 2012 (online)

 
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Key words

catalysis - Amberlite - diamines - benzimidazoles - quinoxalines

Significance

Amberlite resin-bound hexafluorophosphate (Amberlite-PF6) was prepared by treatment of Amberlite 900 with aqueous NaPF6 (eq. 1). In the presence of Amberlite-PF6, the annulation of phenylenediamines 1 with aldehydes 2 took place to give the corresponding benzimidazoles 3 (25 examples, 72–96% yield).


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Comment

The binding of hexafluorophosphate on Amberlite resin was confirmed by IR spectra (557 and 832 cm–1), though other characterizations were not given. Phenylenediamines 1 also reacted with α-bromoketones 4 in the presence of Amberlite-PF6 to give the corresponding quinoxalines 5 via an aromatization step.


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