Continuous Synthesis of Hydantoins: Intensifying the Bucherer-Bergs Reaction
Julia L. Monteiro, Bartholomäus Pieber, Arlene G. Corrêa, C. Oliver Kappe*
*Institute of Chemistry, University of Graz, NAWI Graz, Heinrichstrasse 28, 8010 Graz, Austria, Email: oliver.kappeuni-graz.at
J. L. Monteiro, B. Pieber, A. G. Corrêa, C. O. Kappe, Synlett, 2016, 27, 80-82.
DOI: 10.1055/s-0035-1560317 (free Supporting Information)
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A two-feed flow approach with increased interfacial area of the biphasic reaction mixture and the lack of headspace enables almost quantitative conversions in a continuous Bucherer-Bergs hydantoin synthesis within 32 minutes at 120 °C and 20 bar even for unpolar starting materials. In addition, a selective N(3)-monoalkylation of the resulting heterocycles under batch microwave conditions provides potential acetylcholinesterase inhibitors.
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