90998-35-9Relevant academic research and scientific papers
Revisiting the Ullmann-ether reaction: A concise and amenable synthesis of novel dibenzoxepino[4,5-d]pyrazoles by intramolecular etheration of 4,5-(o,o′-halohydroxy)arylpyrazoles
Olivera, Roberto,SanMartin, Raul,Churruca, Fatima,Dominguez, Esther
, p. 7215 - 7225 (2007/10/03)
A concise synthesis of a series of novel dibenzoxepino[4,5-d]pyrazoles was accomplished by implementation of an intramolecular Ullmann-ether reaction on o,o'-halohydroxy-4,5-diarylpyrazoles mediated by CuBr·DMS. An alternative useful approach based on the palladium-catalyzed biarylether linkage formation (Buchwald-Hartwig reaction) was also successfully applied, offering limitations with regard to the steric demand of the substituents. The synthesis of the key o,o′-halohydroxy-4,5-diarylpyrazole intermediates proceeds through the construction of the heterocyclic ring by a tandem amine-exchange/heterocyclization sequence of 3-N,N-(dimethylamino)-1,2-diarylpropenones with phenylhydrazine followed by basic hydrolysis for deprotection. The enamino ketone precursors were conveniently prepared from the corresponding O-sulfonyloxy and O-benzoyloxy ortho-substituted 1,2-diarylethanones, starting from inexpensive salicylaldehyde or phenylacetic derivatives. Preliminary binding affinity experiments against peripheral and central nervous system receptors have been done with negative results.
FORMATION OF ANOMALOUS PRODUCTS IN THE LEUCKART REACTION OF THE 2-BROMO-4,5-DIMETHOXYBENZYL 2-HYDROXY-3,4-DIMETHOXYPHENYL KETONE
Dominguez, Esther,Lete, Esther,Villa, M. Jesus,Iriondo, Carmen
, p. 1217 - 1224 (2007/10/02)
The Leuckart reaction of the 2-bromo-4,5-dimethoxybenzyl 2-hydroxy-3,4-dimethoxyphenyl ketone (2) afforded, not the expected amine, but three anomalous products: the stilbene (3), the isoflavone (4) and the pyrimidine (5).Their structures have been establ
