An efficient solvent-free synthesis of NH-pyrazoles from β-dimethylaminovinylketones and hydrazine on grinding was written by Longhi, Kelvis;Moreira, Dayse N.;Marzari, Mara R. B.;Floss, Vagner M.;Bonacorso, Helio G.;Zanatta, Nilo;Martins, Marcos A. P.. And the article was included in Tetrahedron Letters in 2010.Formula: C9H7BrN2 This article mentions the following:
A series of NH-pyrazoles was efficiently synthesized from the reaction of β-dimethylaminovinylketones ([R1C(O)C(R2)=CHN(Me2)], where R1 = Me, Ph, 3-MeO-Ph, 4-Me-Ph, 4-MeO-Ph, 4-F-Ph, 4-Cl-Ph, 4-Br-Ph, 4-O2N-Ph, fur-2-yl, thien-2-yl; R2 = H, 2-MeO-Ph; R1, R2 = -(CH2)3C(O)-) and hydrazine sulfate in solid state on grinding in the presence of p-toluenesulfonic acid (PTSA). Most of the reactions proceeded smoothly at room temperature under solvent-free conditions. In comparison with the classical reaction conditions, which employ mol. solvent (ethanol), this new synthetic method has the advantages of shorter times, higher yields, mild reaction conditions as well as being environmentally friendly. In the experiment, the researchers used many compounds, for example, 3-(4-Bromophenyl)-1H-pyrazole (cas: 73387-46-9Formula: C9H7BrN2).
3-(4-Bromophenyl)-1H-pyrazole (cas: 73387-46-9) belongs to pyrazole derivatives. Pyrazole is a weak base, with pKb 11.5 (pKa of the conjugated acid 2.49 at 25 °C).Pyrazole used as a ligand to prepare organometallic compounds. Pyrazole the presence of this nucleus in pharmacological agents of diverse therapeutic categories such as celecoxib, a potent anti-inflammatory, the antidepressant agent fezolamide have proved the pharmacological potential of the pyrazole moiety. Formula: C9H7BrN2
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics