The Chemistry of Acetylpyrazoles and Its Utility in Heterocyclic Synthesis

Abstract

A literature survey revealed that a great deal of interest has been focused on the synthesis of functionalized pyrazole derivatives due to their synthetic and biological potentialities. The pharmacological activities that have been found for some pyrazole derivatives include selective enzyme inhibition, antiviral, estrogen receptor agonist, anti‐inflammatory, anticancer, antiobesity, and antitumor properties. Other activities such as potential inhibitors of HIV‐1, pesticides, fungicides, and antihypertensive agents were reported for other pyrazole derivatives. This review summarizes the synthetic methods and reactions of 3‐acetyl‐pyrazoles, 4‐acetyl‐pyrazoles, and 3,4‐di‐acetyl‐pyrazoles. Most reaction types have been successfully applied and used in the production of biologically active compounds. The aim of this review is to focus mainly on the utility of acetylpyrazole derivatives in the synthesis of heterocyclic compounds during the period 1990–2018.

Synthesis, Characterization and Evaluation of Antimicrobial Activity, Phytotoxicity, Molecular Docking & Dynamic Simulations of Benzothiazole Functionalized C−C Linked Pyrazolyl‐Thiazoles

“…Firstly, the formation of 4‐acetylpyrazoles ( 3 ) has been accomplished in good yield by reacting a mixture of phenylhydrazine/2‐benzothiazolylhydrazine ( 2 ), pentane‐2,4‐dione ( 1 ) and dimethylformaldehyde‐dimethylacetal following modified procedure under solvent‐free condition [25–27] . The 4‐acetylpyrazoles ( 3 ) thus formed were reacted with hydroxy(tosyloxy)benzene (HTIB) in acetonitrile to afford the precursors i. e ., α‐tosyloxy pyrazolylketones ( 4 ) required for the synthesis of pyrazolyl‐thiazoles.…”

“…Firstly, the formation of 4-acetylpyrazoles (3) has been accomplished in good yield by reacting a mixture of phenylhydrazine/ 2-benzothiazolylhydrazine (2), pentane-2,4-dione (1) and dimethylformaldehyde-dimethylacetal following modified procedure under solvent-free condition. [25][26][27] The 4-acetylpyrazoles (3) thus formed were reacted with hydroxy(tosyloxy)benzene (HTIB) in acetonitrile to afford the precursors i. e., α-tosyloxy pyrazolylketones (4) required for the synthesis of pyrazolylthiazoles. Utilizing α-tosyloxy pyrazolylketones (4) over α-halo pyrazolylketones is advantageous from enviornmental, health, synthetic and free from formation of vulnerable point of view as the latter are lachrymatory in nature.…”

Non-K Region Disubstituted Pyrenes (1,3-, 1,6- and 1,8-) by (Hetero)Aryl Groups—Review

“…Apart from 1,6- and 1,8-dibromopyrenes, the significant role as a starting material in the synthesis of 1,6-, 1,8-, and 1,3-disubstituted pyrenes by heteroaryl groups play acetylpyrenes due to the wide possibility of functionalization of an acetyl group [72]. Their synthesis is based on the acylation of pyrene using acetyl chloride (AcCl), what resulted in disubstituted and various isomers of acetylpyrenes (Scheme 47).…”