Synthetic Studies Connected with the Preparation of N-[3-(3-Cyanopyrazolo[1,5-a]pyrimidin-5-yl)phenyl]-N-ethylacetamide, a Zaleplon Regioisomer
作者:Stanislav Rádl、Michaela Blahovcová、Marcela Tkadlecová、Jaroslav Havlíček
DOI:10.3987/com-09-s(s)129
日期:——
N-[3-(3-Cyanopyrazolo[1,5-a]pyrimidin-5-yl)phenyl]-N-ethyl-acetamide, a principal impurity of zaleplon, is prepared by Suzuki-Miyaura cross coupling reaction of the corresponding boronic acid and/or boronates with 5-chloropyrazolo[1,5-a]pyrimidin-3-carbonitrile (7). Various methods of preparation of both components are described, as well as approaches based on the final modification of the 5-(3-aminophenyl)-pyrazolo[1,5-a]pyrimidine-3-carbonitrile moiety prepared by Suzuki-Miyaura cross coupling. All the prepared compounds were unambiguouesly identified by NMR techniques. Spectral characteristics (IR, UV, MS) of these compounds are also given.