Synthesis and herbicidal activity of phenyl‐substituted benzoylpyrazoles

Abstract

A novel series of substituted 3-phenyl benzoylpyrazoles were prepared and tested as potential grass herbicides. The targeted materials were prepared by three newly developed synthetic routes, which allowed a comprehensive study of the SAR (structure-activity relationships) of this series. The best combination of grass weed activity (Avena fatua L, Setaria viridis (L) Beauv and Alopecurus myosuroides Huds) and wheat selectivity was obtained with an alkoxy group in the 4-position of the phenyl ring. Activity was further enhanced by the presence of tert-butyl on the pyrazole and a methyl group at the C-2 position of the benzoyl moiety. The alkoxy-substituted 3-phenylbenzoylpyrazoles are a novel class of herbicides with potential utility for control of important grass weeds in cereals.

Regiospecific preparation of 1,4,5-trisubstituted pyrazoles from 2-(1H-1,2,3-benzotriazol-1-yl)-3-(4-aryl)-2-propenals

“…The reaction mixture was allowed to warm to room temperature while stirring for 2 h, quenched by the addition of saturated NH 4 Cl, and extracted with ether. The combined extracts were washed with brine, dried over MgSO 4 and the solvent was evaporated under reduced pressure.…”

Pyrazolo[4,3-a]quinindoline as a new highly fluorescent heterocyclic system: Design, synthesis, spectroscopic characterization and DFT calculations

“…Alongside the traditional pyrazole dyes [6], couplers for photographic materials [7], herbicides [8], and luminescent and fluorescent substances [9], pyrazoles with antiarrhythmic [10] and cholesterol synthesis-inhibiting activities [11] have appeared. Other pyrazoles include effective antirheumatoidal (SC-58635 Celecoxib) [12] and antiviral agents (Pyrazomycin) [13], hormone oxytocin agonists (WAY-VNA-932) [14] and selective Human C1s inhibitors [15].…”

Mild and efficient oxidation of 2-pyrazolines and isoxazolines by trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxalane–NH4Cl–HOAc in water–MeCN

“…Several isoxazoles and pyrazoles have agrochemical herbicidal and soil fungicidal activity and act as pesticides and insecticides [7,8]. Isoxazoles and pyrazoles are also useful synthetic intermediates capable of undergoing a variety of transformations and transition-metal catalyzed cross-coupling reactions, for example Heck, Stille, Suzuki, Sonogashira, and Negishi coupling [9].…”