84263-08-1Relevant academic research and scientific papers
Diastereodivergent and enantioselective access to spiroepoxides via organocatalytic epoxidation of unsaturated pyrazolones
Meninno, Sara,Roselli, Angelo,Capobianco, Amedeo,Overgaard, Jacob,Lattanzi, Alessandra
, p. 5030 - 5033 (2017)
Readily available chiral amine-thioureas are effective catalysts for the first diastereo- and enantioselective epoxidation of unsaturated pyrazolones. The trans- or cis-spiroepoxides are preferentially obtained in good yield and high to excellent enantios
A New Synthesis of 4,5-Dihydroxy-pyrazoles
Kirschke, Klaus,Schmitz, Ernst
, p. 35 - 44 (2007/10/02)
1-Aryl-pyrazolin-5-ones 1 are converted by Knoevenagel condensation with acetone or by reaction with 2,2-dimethyl-1,3-dioxolane 6 to 1-aryl-4-isopropyliden-pyrazolin-5-ones 2.The compounds 2 are epoxidized by hydrogen peroxide forming the spiro-epoxides 3, which can be cleaved to 4,5-dihydroxy-pyrazoles 4 under acidic conditions. 4-Acetoxy-5-hydroxy-pyrazoles 13 are formed directly, when 3 are cleaved in presence of acetic anhydride.The 3,3',3'-trimethyl-1-(4-nitro-phenyl)-pyrazolin-4-spiro-2'-oxiran-5-one 3b undergoes rearrangement to the 1,3-dioxolopyrazole 12.
Oxopyrazoline-spiro-oxirans. A New Class of Reactive Heterocycles
Ege, Seyhan N.,Adams, Alan. D.,Gess, E. Joseph,Ragone, Katherine S.,Kober, Brian J.,et al.
, p. 325 - 332 (2007/10/02)
Chemical and spectral properties of a series of 1-oxa-5,6-diazaspirohept-6-en-4-ones, synthesized by the oxidation of 4-alkylidene- or 4-arylidene-1-aryl-2-pyrazolin-5-ones are reported
