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Advisor(s)
Abstract(s)
Palladium or copper catalyzed aminations or amidations were performed to obtain diarylamines and diarylacetamides precursors
of thienocarbazoles. The fact that an ortho-bromodiarylamine did not cyclize to the corresponding thienocarbazole under conditions known
for carbazoles from ortho-halodiphenylamines, conducted us to a highly efficient method of palladium-catalyzed intramolecular cyclization
with N-deprotection of ortho-halodiarylacetamides to thienocarbazoles. Other method of intramolecular cyclization of diarylamines based
on the reoxidation of the Pd(0) formed by Cu(OAc)2, avoiding the use of stoichiometric amounts of Pd(OAc)2, gave thienocarbazoles in a
moderate yield, including a ring A methoxylated compound. An attempt to combine palladium and copper catalyses in a ‘one pot’ reaction of
amination and intramolecular cyclization gave as major product a N-benzo[b]thiophene substituted carbazole and the required
thienocarbazole in low yield.
Description
Keywords
C–N coupling Copper Palladium Cyclization–deprotection
Citation
Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Kirsch, Gilbert (2002).
Novel synthetic routes to thienocarbazoles via palladium or copper catalyzed amination or amidation of arylhalides and intramolecular cyclization. Tetrahedron. ISSN 0040-4020. 58:39, p. 7943-7949
Publisher
Elsevier