309297-08-3Relevant academic research and scientific papers
A Combination of Tandem Amine-Exchange/Heterocyclization and Biaryl Coupling Reactions for the Straightforward Preparation of Phenanthro[9,10-d]pyrazoles
Olivera, Roberto,SanMartin, Raul,Dominguez, Esther
, p. 7010 - 7019 (2007/10/03)
The tandem amine-exchange/heterocyclization of enaminoketones is successfully applied to the regioselective preparation of a series of new 4,5-diarylpyrazoles by reaction of phenylhydrazine and several 3-N,N-(dimethylamino)-1,2-diarylpropenones. The comparison of a vast array of biaryl coupling procedures provides general, complementary approaches to new phenanthro[9,10-d]-pyrazoles. The most efficient procedures for this final step in the construction of the tetracyclic system are based on a Stille-type tandem stannylation - biaryl coupling of o,o′-dihalogenated diarylpyrazoles and an hypervalent iodine-mediated nonphenolic oxidative coupling of nonhalogenated precursors.
A straightforward synthetic pathway to phenanthro[9,10-d]heterocycles
Olivera, Roberto,SanMartin, Raúl,Domínguez, Esther
, p. 1028 - 1030 (2007/10/03)
A series of new 4,5-o,o-bis(haloaryl)pyrazoles was regioselectively prepared by a tandem amine exchange/heterocyclization. The intramolecular Stille-type biaryl coupling of the so-obtained pyrazole derivatives and previously prepared diarylisoxazoles led with high overall yields to the isolation of new phenanthro[9,10-d]pyrazoles and phenanthro[9,10- d]isoxazoles, respectively. The formation of dehalogenation products was efficiently avoided by use of heavy-wall pressure tubes.
