1-Aryl-2-chloro-5-methoxy-1 H -3-pyrrolecarbaldehyde as Synthons for Fused Heterocycles: Synthesis of Pyrazolo[3,4- d ]pyrrolo[2,3- b ]pyridine Derivatives
Free accessResearch articleFirst published online May, 2004
1-Aryl-2-chloro-5-methoxy-1 H -3-pyrrolecarbaldehyde as Synthons for Fused Heterocycles: Synthesis of Pyrazolo[3,4- d ]pyrrolo[2,3- b ]pyridine Derivatives
Pyrazolo[3,4-d]pyrrolo[2,3-b]pyridine derivatives (6a–f) were obtained by oxidation of tosylhydrazones of 2-allylamino-5-methoxypyrrole-3-carbaldehydes (3a–f) with lead tetraacetate. The nitrilimine intermediates (5a–f) underwent intramolecular 1,3-dipolar cycloaddition to yield the tricyclic heterocycles 6a–f in good yields.
