Synthesis of diarylamines in the benzo[b]thiophene series bearing electron dona...

• Author(s): Ferreira, Isabel C.F.R. ; Queiroz, Maria João R.P. ; Kirsch, Gilbert
• Date: 2003
• Persistent ID: http://hdl.handle.net/10198/818
• Origin: Biblioteca Digital do IPB
• Subject(s): Buchwald–Hartwig coupling; Palladium; Amination; Diarylamines; Benzo[b]thiophenes
• Document Type: Article
• Language: English

Description

Diarylamines in the benzo[b]thiophene series bearing electron donating or withdrawing groups, were prepared by Buchwald– Hartwig C–N coupling in moderate to high yields. The conditions used were Pd(OAc)2 (3 mol%), BINAP as ligand (4 mol%) and Cs2CO3 as base (1.4 equiv.), in toluene at 1008C, being 6-bromo or amino benzo[b]thiophenes coupled, respectively, with substituted anilines or phenylbromides. The 6-aminobenzo[b]thiophene derivatives were also prepared by palladium catalyzed C–N coupling of the corresponding 6-bromo compounds with benzophenone imine, followed by acidic hydrolysis of the imino derivatives. When 4-nitrobromobenzene and 4-bromobenzonitrile were used as coupling components, triarylamines were also isolated in small amounts. The presence of a fluorine atom on the phenylbromide highly increases the diarylamine yields