Pyrrolyl-pyrazoles

C-Ethenylpyrroles 140 proved to be rewarding starting materials for the synthesis of diverse functionalized heterocyclic assemblies with pyrrole moieties pyrrolyl-pyrazoles (99RJ01214, OOSULl, 01RJO1736),... 

Sobenina, L.N., A.P. Demenev, A.I. Mikhaleva et al. 2000. Synthesis and reactions with carbon disulfide of 5-amino-3-(2-pyrrolyl)pyrazoles. Sulfur Lett 24 (1) 1-12. 

Ethanone, 1 -(methyl-1 H-pyrrolyl)-Ethanone, 1-(1/-/-pyrazol-3-yl)-Ethanone, 1-(1/-/-pyrazol-4-yl)-Ethanone, 1-(1/-/-pyrrol-2-yl)-... 

This strategy was expanded by Odom [350], who showed that Ti-pyrrolyl complexes can also be used in a multicomponent coupHng reaction to prepare a variety of pyrazole products. In this case, the coupHng of an alkyne, isonitrile, and amine results in the synthesis of the tautomer of 1,3-dimines in situ, which can then undergo cyclization with parent hydrazine and hydrazine derivatives to furnish the targeted pyrazoles in one-pot procedure (Scheme 15.115). This strategy has been extended to the preparation of the natural product withasomnine (Section 15.4.5). 

---