K. Josef, R. Dandu, M. Tao
May 1, 2006
Citations
0
Influential Citations
7
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Journal
Journal of Heterocyclic Chemistry
Abstract
This paper communicates the (regio) synthesis and a convenient NMR structural assignment method for N-methyl-tetrahydro-5H-indazol-5-one isomers. The cyclization reaction of 7-(hydroxymethylene)-1,4-dioxaspiro[4,5]decan-8-one (3) with methylhydrazine yields, after de-protection predominately the N-2 methyl isomer 2. Analysis of the product ratio and structural assignments are based on NMR data including NOE difference experiments and subsequently confirmed with X-ray crystallography. These findings are in sharp contrast with the literature. The experimental conditions used to optimize the synthesis of the individual isomers are discussed.