Ester hydrolysis with 2,6-di(pyrazol-3-yl)pyridines and their CoII complexes in homogeneous and micellar media
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Updated: Oct 7, 2026

Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines
Published on: June 23, 2019
R Jairam1, M L Lau, J Adorante
1Department of Chemistry, York University, Toronto, Ontario, Canada.
Abstract:
The 1:1 complex of Co(ClO4)2 with the H2O-insoluble tridentate 2,6-di(1H-4,5,6,7-tetrahydroindazol-3-yl)pyridine (H21) was found to be an excellent catalyst for the hydrolysis of para-nitrophenyl acetate in aqueous buffers over the pH 7.05-7.90 range, with an estimated second-order rate constant of 0.50 M(-1) s(-1). The Co2+ complexes of the N,N'-di-1-dodecyl analogue in micellar media and the N,N'-di-(4-carboxyphenyl) analogue in aqueous media were much poorer catalysts, poorer than the free ligands. In all cases, the pH-rate profiles indicated that free base, deprotonated or hydroxo forms were the active species. The greater success with Co(H(2)1)2+ indicated a catalytic role for N-H deprotonation.
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