Domino reaction of arylglyoxals with pyrazol-5-amines: selective access to pyrazolo-fused 1,7-naphthyridines, 1,3-diazocanes, and pyrroles

J Org Chem. 2014 Jun 6;79(11):5258-68. doi: 10.1021/jo500823z. Epub 2014 May 22.

Abstract

New multicomponent domino reactions of arylglyoxals with pyrazol-5-amines have been established, providing selective access to unprecedented pyrazolo-fused 1,7-naphthyridines, 1,3-diazocanes, and pyrroles (up to 52 examples). The unreported dipyrazolo-fused 1,7-naphthyridines were regioselectively synthesized through a special double [3 + 2 + 1] heteroannulation accompanied by direct C-C formation between two electrophilic sites of arylglyoxals. The unusual [3 + 3 + 1 + 1] cyclization resulted in 20 examples of novel dipyrazolo-fused 1,3-diazocanes, whereas pyrrolo[2,3-c]pyrazoles were obtained in good yields by varying arylglyoxals 1 and pyrazol-5-amines 2 in the ratio 1:2. Mechanisms of formation of these three new types of heterocycles are also proposed.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amines / chemistry*
  • Catalysis
  • Glyoxylates / chemistry*
  • Molecular Structure
  • Naphthyridines / chemistry*
  • Pyrazoles / chemistry*
  • Pyrroles / chemistry*
  • Stereoisomerism

Substances

  • Amines
  • Glyoxylates
  • Naphthyridines
  • Pyrazoles
  • Pyrroles