84752-11-4Relevant academic research and scientific papers
1,3-Dipolar Cycloaddition Reactions of Diazopyrazolinones with Electron-Deficient Dipolarophiles
Padwa, Albert,Woolhouse, Anthony D.,Blount, John J.
, p. 1069 - 1074 (2007/10/02)
A study of the reactivity of a series of 4-diazopyrazolin-5-ones toward dipolar cycloaddition with electron-deficient olefinic and acetylenic dipolarophiles has been carried out.Reactions with dimethyl acetylenedicarboxylate afford pyrazolotriazin-7-ones which result from dipolar cycloaddition followed by a van Alphen-Huttel rearrangement of the initially produced spiro 3H-pyrazole adducts.Reaction with unsymmetrical acetylenic esters afforded variable mixtures of regioisomeric pyrazolotriazinones and 1H-furopyrazoles.Product formation has been rationalized in terms of a sustituent-dependent partitioning between spiro 3H-pyrazole adducts and ring-opened diazoalkanes.Spirocarboxylate esters were the only products isolated from reactions with acrylate ester.
