Pyrroles and Pyrazoles by a C-N Coupling-Hydroamination Sequence

Copper(II)-mediated regioselective N-arylation of pyrroles, indoles, pyrazoles and carbazole via dehydrogenative coupling.

A copper(II)-mediated regioselective N-arylation of azoles has been developed using 8-aminoquinoline amide as a directing group. This reaction shows a broad substrate scope with different azoles such as pyrroles, indoles, pyrazoles and carbazole with good yields.

Nucleophilic ortho-Allylation of Pyrroles and Pyrazoles: An Accelerated Pummerer/Thio-Claisen Rearrangement Sequence

Arylsulfinyl groups direct the metal-free, regiospecific, nucleophilic ortho-allylation of pyrroles and pyrazoles. Mechanistic studies support the intermediacy of allylsulfonium salts that undergo facile thio-Claisen rearrangement onto the heterocyclic ring, giving products of coupling. The strategy has been adapted to allow regiospecific propargylation of the heterocyclic substrates.

Hydroamination/hydrosilylation sequence catalyzed by titanium complexes.

N-methyl pyridinium-p-toluene Sulfonate (NMPyTs) catalyzed synthesis of pyrano[2,3-c]pyrazoles

Abstarct:A simple one-pot synthesis of pyrano[ 2,3-c]pyrazoles was developed by a three-component reaction of various benzaldehydes, malononitrile and 1-phenyl or hydro-3-methyl-1H-pyrazol-5(4H)-one in the presence of N-methyl pyridinium p-toluene sulfonate (NMPyTs) as a catalyst. All of the synthesized compounds were identified by IR, 1H NMR, 13C NMR and mass spectroscopy techniques. In the me...

Synthesis of 3,5-disubstituted pyrazoles via Cope-type hydroamination of 1,3-dialkynes.

An efficient method for the synthesis of 3,5-disubstituted pyrazoles is described. The reactions of 1,3-dialkynes with hydrazine proceeded smoothly in dimethyl sulfoxide under mild reaction conditions to produce 3,5-disubstituted pyrazoles in satisfactory to excellent yields. A one-pot procedure of the transformation has been developed.