Synthesis of indolo[1,2-c]quinazolines from 2-alkynylaniline derivatives through Pd-catalyzed indole formation/cyclization with N,N-dimethylformamide dimethyl acetal.

ABSTRACT: An efficient strategy for the synthesis of 6-unsubstituted indolo[1,2-c]quinazolines is described. The Pd-catalyzed reaction of o-(o-aminophenylethynyl) trifluoroacetanilides with Ar-B(OH)₂ afforded 2-(o-aminophenyl)-3-arylindoles, that were converted to 12-arylindolo[1,2-c]quinazolines by adding dimethylformamide dimethyl acetal (DMFDMA) to the reaction mixture after extractive work-up. This reaction outcome is different from the previously reported Pd-catalyzed sequential reaction of the same substrates with Ar-I, Ar-Br and ArN₂⁺BF₄^-, that afforded 12-arylindolo[1,2-c]quinazolin-6(5H)-ones. Moreover, 12-unsubstituted indolo[1,2-c]quinazolines can be obtained both by reacting 2-(o-aminophenyl)indoles with DMFDMA or by sequential Pd-catalyzed reaction of o-(o-aminophenylethynyl)aniline with DMFDMA.

SUBMITTER: Arcadi A 

PROVIDER: S-EPMC6142776 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature