Structural and conformational analysis of 1-oxaspiro[2.5]octane and 1-oxa-2-azaspiro[2.5]octane derivatives by 1H, 13C, and 15N NMR
作者:Rubén Montalvo-González、Armando Ariza-Castolo
DOI:10.1002/mrc.3792
日期:2012.1
A structural and conformational analysis of 1-oxaspiro[2.5]octane and 1-oxa-2-azaspiro[2.5]octane derivatives was performed using (1) H, (13) C, and (15) N NMR spectroscopy. The relative configuration and preferred conformations were determined by analyzing the homonuclear coupling constants and chemical shifts of the protons and carbon atoms in the aliphatic rings. These parameters directly reflected
Convenient one-pot syntheses of pyrazoles from imines, a vilsmeier type reagent and hydrazine
作者:Alan R. Katritzky、Anna Denisenko、Sergey N. Denisenko、Michael Arend
DOI:10.1002/jhet.5570370548
日期:2000.9
one-pot procedure for the regioselective synthesis of pyrazoles from readily available starting materials is described. Vilsmeier type reagent 1 reacts with imines 10 (via the corresponding tautomeric secondary enamines) in tetrahydrofuran to give enaminoimine hydrochlorides 11. Nonsymmetrical imines generally react preferentially with 1 at the sterically less hindered α-position. The enaminoimine hydrochlorides