1,3,5-triaryl-2-pyrazolines is described. The solvent ethyl lactate, obtained from renewable sources, is biodegradable. The catalyst \(\hbox CeCl}_3} \cdot 7\hbox H}_2}\hbox O}\) is a water-tolerant Lewis acid with low toxicity. Easy and clean work up, recyclable solvent and catalyst are merits of the protocol. The reaction works well for all systems giving good yields of the desired products.
Nanorod vanadatesulfuric acid (VSA NRs), as a recyclable and ecologically benign catalyst, was used for the one‐pot synthesis of chalcones and 1,3,5‐triaryl‐2‐pyrazolines (TAPs). Chalcones were prepared via the condensation of substituted acetophenones with aryl‐aldehydes under solvent‐free conditions. Subsequently, the synthesized chalcones were used for the catalytic synthesis of TAPs via two‐component
Convenient Synthesis of Highly Functionalized Pyrazolines via Mild, Photoactivated 1,3-Dipolar Cycloaddition
作者:Yizhong Wang、Claudia I. Rivera Vera、Qing Lin
DOI:10.1021/ol7017328
日期:2007.10.1
cycloaddition procedure was successfully developed for the synthesis of polysubstituted pyrazolines. This procedure involved the in situ generation of the reactive nitrile imine dipoles using a hand-held UV lamp at 302 nm, followed by spontaneous cycloaddition with a broad range of 1,3-dipolarophiles with excellent solvent compatibility, functional group tolerance, regioselectivity, and yield.
An efficient aromaticthiocyanation of 1,3,5-trisubstituted pyrazolines occurred regioselectively at the para position of N-benzene rings using ammonium thiocyanate as a thiocyanation reagent and oxone as an oxidant.
Trichloroisocyanuric acid as a novel oxidizing agent for the oxidation of 1,3,5-trisubstituted pyrazolines under both heterogeneous and solvent free conditions
作者:Mohammad Ali Zolfigol、Davood Azarifar、Behrooz Maleki
DOI:10.1016/j.tetlet.2004.01.038
日期:2004.3
Trichloroisocyanuric acid is used as an effective oxidizing agent for the oxidation of 1,3,5-trisubstitutedpyrazolines to their corresponding pyrazoles under both heterogeneous and also solvent free conditions with good yields at room temperature.