One-Pot Synthesis of 1-Aryl-3-trifluoromethylpyrazoles Using Nitrile Imines and Mercaptoacetaldehyde As a Surrogate of Acetylene
Kamil Świątek, Greta Utecht‐Jarzyńska, Marcin Palusiak, Jun‐An Ma, Marcin Jasiński
Abstract
High Resolution Image Download MS PowerPoint Slide A synthetically useful approach for one-pot preparation of 1-aryl-3-trifluoromethylpyrazoles using in situ generated nitrile imines and mercaptoacetaldehyde applied as 1 equiv of acetylene is presented. This protocol comprises (3 + 3)-annulation of the mentioned reagents to form 5,6-dihydro-5-hydroxy-4 H -1,3,4-thiadiazine, followed by cascade dehydration/ring contraction reactions with p -TsCl. In addition, representative nonfluorinated analogues functionalized with Ph, Ac, and CO 2 Et groups at the C(3)-position of the pyrazole ring were also prepared by the devised method.
Topics & Concepts
ChemistryNitrileAnnulationAcetyleneArylRing (chemistry)Combinatorial chemistryReagentPyrazoleDehydrationOrganic chemistryMedicinal chemistryCatalysisAlkylBiochemistryFluorine in Organic ChemistrySynthesis and Biological EvaluationSynthesis and Reactions of Organic Compounds