No abstract

A simple and efficient method for synthesis of 5,7‐disubstituted pyrazolo[1,5‐a]pyrimidines is reported. The synthetic route involved first a one‐pot two‐step synthesis of 7‐substituted pyrazolo[1,5‐a]pyrimidin‐5‐ones from the reaction of 3‐aminopyrazole 1 with activated alkynes. These compounds were used as key intermediates to access, with excellent yields, a library of new 5,7‐disubstituted pyrazolo[1,5‐a]pyrimidines, which are known for their wide range of biological activities, through C–O bond activation with PyBroP (bromotripyrrolidinophosphonium hexafluorophosphate) as an activator reagent.

A convenient and efficient synthetic route to C3-arylated 7-trifluoromethylpyrazolo[1,5-a]pyrimidin-5-one derivatives has been reported starting from 3-bromo-7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidin-5-one through a Suzuki–Miyaura cross-coupling reaction.

An efficient and original synthesis of various 3,5-disubstituted 7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidines is reported. A library of compounds diversely substituted in C-3 and C-5 positions was easily prepared from a common starting material, 3-bromo-7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidin-5-one. In C-5 position, a SNAr type reaction was achieved by first activating the C–O bond of the lactam function with PyBroP (Bromotripyrrolidinophosphonium hexafluorophosphate), followed by the addition of amine or thiol giving monosubstituted derivatives, whereas in C-3 position, arylation was performed via Suzuki–Miyaura cross-coupling using the commercially available aromatic and heteroaromatic boronic acids. Moreover, trifluoromethylated analogues of potent Pim1 kinase inhibitors were designed following our concise synthetic methodology.

Three of polyanthraquinone sulfide (PAQS) isomers were synthesized, characterized and included in a comparative study of electrochemical performances as organic material cathode. The performances of the 1,5-PAQS, 2,6-PAQS, and 1,8-PAQS...

Fluoromethylated imidazo[1,2-a]pyrimidines and benzimidazo[1,2-a]pyrimidines were synthesized through Michael addition/intramolecular cyclization reaction by condensation of 2-amino imidazole derivatives with ethyl 4,4,4-trifluorobut-2-ynate and using C–O bond activation.

A variety of novel disubstituted 2-(alknyl, aryl and arylamine)-6-alkynylpyrazolo[1,5-a]pyrimidine derivatives was prepared via sequential site-selective cross-coupling reactions from 2,6-dibromopyrazolo[1,5-a]pyrimidine 3. The regio-controlled Sonogashira-type coupling of 3 with a wide range...

An efficient regioselective cross-coupling reactions of tert-butyl 2,4-dibrominated-5-methyl-1H-imidazole-1-carboxylate is reported. This new synthetic route runs under simple and mild conditions and selectively gives an easy access to 2,4-dialkynylated and 2-alkynylated-4-arylated-1H-imidazole-1-carboxylate in good to excellent yields.