M. Sedlák, Pavel Drabina, Václav Lánský
May 1, 2008
Citations
0
Influential Citations
4
Citations
Journal
ChemInform
Abstract
Reactions of 3-chlorobenzo[b]thiophene-2-carbonyl chloride with 2-alkyl-2-aminopropanamides have been used to prepare a series of carboxamides 1a-d (yields 61-85%). The products were submitted to base-catalysed ring closure reactions to give the corresponding 4,5-dihydro-1H-imidazol-5-ones 2a-d (yields 69-97%). By N-methylation and N-benzylation were prepared the corresponding 1-alkyl derivatives 3a(91%) and 3b (85%). These two alkyl derivatives were studied from the standpoint of potential replacement of 3-chlorine substituent by piperidine via the Buchwald-Hartwig reaction. It was found that the reaction gives besides except required products of C-N coupling 5a (14%) and 5b (12%) also products of reductive dechlorination 4a (max. 57%) and 4b (max. 56%). The reductive dechlorination product 4a is formed exclusively (42%) if butyl-di-(1-adamantyl)phosphine (BDAP) is used.