Preparation of 3,4-Substituted-5-Aminopyrazoles and 4‑Substituted-2-Aminothiazoles
datasetposted on 21.11.2018, 00:00 by Stepan Havel, Prashant Khirsariya, Naresh Akavaram, Kamil Paruch, Benoit Carbain
3,4-Substituted-5-aminopyrazoles and 4-substituted-2-aminothiazoles are frequently used intermediates in medicinal chemistry and drug discovery projects. We report an expedient flexible synthesis of 3,4-substituted-5-aminopyrazoles (35 examples), based on palladium-mediated α-arylation of β-ketonitriles with aryl bromides. A library of 4-substituted-2-aminothiazoles (21 examples) was assembled by a sequence employing Suzuki coupling of newly prepared, properly protected pinacol ester and MIDA ester of 4-boronic acid-2-aminothiazole with (hetero)aryl halides.