Ivachtchenko, Alexandre V.; Kravchenko, Dmitry V.; Zheludeva, Valentina I.; Pershin, Dmitry G. published their research in Journal of Heterocyclic Chemistry on December 31 ,2004. The article was titled 《Synthesis of pinacol esters of 1-alkyl-1H-pyrazol-5-yl- and 1-alkyl-1H-pyrazol-4-ylboronic acids》.Quality Control of N,N-Dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole-1-propanamine The article contains the following contents:
1-Substituted pyrazolylboronic acids and their pinacol esters were prepared by lithiation-borylation reaction sequence starting from bromopyrazoles. Alkylation of 4-bromo-1H-pyrazole gave 1-alkyl-4-bromo-1H-pyrazoles, which were lithiated at -80° and borylated with B(OMe)3 to give 1-R-1H-pyrazole-4-boronic acids [4a-g, R = Me, Et, Pr, (CH2)2CHMe2, (CH2)2OMe, (CH2)3NMe2, (CH2)2CH(OEt)2]. Lithiation of 4-bromo-1-(2-dimethylaminoethyl)-1H-pyrazole (2h) gave 5-lithio-derivative, which on borylation afforded 1-R1-4-Br-1H-pyrazole-5-boronic acid (8). Boronic acids 4a-g are unstable and were deborylated slowly due to hydrolysis by traces of water; the stability of boryl derivatives can be greatly enhanced by converting to corresponding pinacol boronates (10a-g). Direct lithiation of 1-R2-1H-pyrazoles by BuLi at -20° afforded 5-lithio-derivatives, which were converted to corresponding 1-R2-1H-pyrazole-5-boronic acids [17a-e; R2 = Me, iBu, Pr, (CH2)2CHMe2, (CH2)2CH(OEt)2] and their pinacol boronates (18a-e, same R2). The key step in the described methodol. is the regioselective lithiation of the pyrazole ring. The synthesized pinacolates are stable under prolonged storage and can be used as convenient reagents in organic synthesis. In the experiment, the researchers used many compounds, for example, N,N-Dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole-1-propanamine(cas: 847818-72-8Quality Control of N,N-Dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole-1-propanamine)
N,N-Dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole-1-propanamine(cas: 847818-72-8) belongs to pyrazoles. Pyrazoles are commonly used scaffold molecules in drug discovery projects. The use of pyrazole derivatives is based on their analgesic, monoamine oxidase inhibitory, anti-inflammatory, antipyretic, neuroleptic, anticonvulsant, antiarrhythmic, sedative, muscle relaxant, antidiabetic and antibacterial activities. Quality Control of N,N-Dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole-1-propanamine
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics