Ivachtchenko, Alexandre V. et al. published their research in Journal of Heterocyclic Chemistry in 2004 | CAS: 847818-76-2

1-Propyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (cas: 847818-76-2) belongs to pyrazole derivatives. Pyrazoles, a five-membered heterocycle containing two adjacent nitrogen atoms, are the core structures found in a number of molecules that possess a wide range of pharmaceutical and agricultural activities. Protonation of pyrazole in strong acid leads to pyrazolium cations, which undergo electrophilic substitution preferentially at C3 rather than C4. The pyrazole anion is not reactive toward nucleophiles but is mostly reactive to electrophiles.Reference of 847818-76-2

Synthesis of pinacol esters of 1-alkyl-1H-pyrazol-5-yl- and 1-alkyl-1H-pyrazol-4-ylboronic acids was written by Ivachtchenko, Alexandre V.;Kravchenko, Dmitry V.;Zheludeva, Valentina I.;Pershin, Dmitry G.. And the article was included in Journal of Heterocyclic Chemistry in 2004.Reference of 847818-76-2 The following contents are mentioned in the article:

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. This study involved multiple reactions and reactants, such as 1-Propyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (cas: 847818-76-2Reference of 847818-76-2).

1-Propyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (cas: 847818-76-2) belongs to pyrazole derivatives. Pyrazoles, a five-membered heterocycle containing two adjacent nitrogen atoms, are the core structures found in a number of molecules that possess a wide range of pharmaceutical and agricultural activities. Protonation of pyrazole in strong acid leads to pyrazolium cations, which undergo electrophilic substitution preferentially at C3 rather than C4. The pyrazole anion is not reactive toward nucleophiles but is mostly reactive to electrophiles.Reference of 847818-76-2

Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics