Heterocycle formation from 1,3-dinitroalkanes. A novel pyrazole synthesis
F. Gabrera Escribano, M.P. Derri Alcantara and A. Gomez-Senchez. Tetrahedron Letters, Vol. 29, No. 46, pp. 6001-6004, 1988
Aliphatic nitro compounds have proved to be useful starting materials in organic synthesis. When the nitro compounds are properly substituted they can cyclize, yielding heterocyclic compounds. 1,3-Dinitroalkanes can be viewed as synthetic equivalents for 1,3-dicarbonyl compounds through a Nef, or equivalent, reaction, and therefore could be ultimately converted into azole heterocycles. Application of the Nef reaction under the usual conditions (NaOH; conc. H2SO4) to 1,3-dinitroalknes gives only trace amounts of the anticipated dione, although the yields can be increased (up to 40%) using a secondary amine as the base. We now find that 1,3-dinitroalkanes react with hydrazines giving rise to pyrazoles.
