Enantioselective Amination of 4-Substituted Pyrazolones Catalyzed by Oxindole-Containing Thioureas and by a Recyclable Linear-Polymer-Supported Analogue in a Continuous Flow Process
作者:Rodrigo Sánchez-Molpeceres、Laura Martín、Noelia Esteban、Jesús A. Miguel、Alicia Maestro、José M. Andrés
DOI:10.1021/acs.joc.3c02069
日期:2024.1.5
azodicarboxylates mediated by a novel quinine-derived thiourea with a 3,3-diaryl-oxindole scaffold is reported. This synthetic method furnished 4-amino-5-pyrazolones in high yields and with excellent enantioselectivities (up to 97:3 er) at room temperature in short reaction times. Moreover, a linear-polymer-supported bifunctionalthiourea, synthesized by reacting a bifunctional aromatic monomer (biphenyl)
SOLID-PHASE SYNTHESIS OF POLYMER-BOUND β-KETOESTERS AND THEIR APPLICATION IN THE SYNTHESIS OF STRUCTURALLY DIVERSE PYRAZOLONES
作者:Lutz F Tietze、Adrian Steinmetz、Friedhelm Balkenhohl
DOI:10.1016/s0960-894x(97)00209-6
日期:1997.5
An efficient solid-phase synthesis of different polymer-bound beta-ketoesters 7 is described using readily available acid chlorides I and haloalkanes 6 as building blocks. The corresponding pyrazolones 9 and 10 were obtained by mild acid catalyzed reaction with phenylhydrazine or by treatment with hydrazine under cyclisation and cleavage from the resin in high purity and good yield. (C) 1997 Elsevier Science Ltd.
A Novel Synthesis of 4-Pyridazineacetic Acids<i>via</i>Ring Expansion of<i>N</i>-Cyanomethylated 3-Pyrazoline-4-acetic Acids
A novel synthetic route to 4‐pyridazineacetic acids 10–12 has been achieved by the ring‐expansion reaction of N‐cyanomethylated 3‐pyrazoline‐4‐acetic acids 7–9. 1H‐Pyrazole‐4‐acetic acids 1–3 were reacted with iodoacetonitrile in the presence of triethylamine in refluxing acetonitrile to give the corresponding C‐cyanomethylated 1H‐pyrazole‐4‐acetic acids 4–6 as major products together with N‐cyanomethylated