133362-10-4Relevant articles and documents
Mechanism of Reaction of Isomeric Nitrolic Acids to Nitrile Oxides in Aqueous Solution
Egan, Carmel,Clery, Maurice,Hegarty, Anthony F.,Welch, Alan J.
, p. 249 - 256 (2007/10/02)
Both E and Z isomers of acetonitrolic acids 15 and 16 can be prepared when the OH group is protected by acetylation.Photoisomerization of the E-isomer resulted in quantitative conversion into the pure Z-isomer 16.Hydrolysis of the E-isomer 15 produced the parent nitrolic acid 14 which undergoes loss of NO2(1-) from the conjugate base at high pH.This reaction is however relatively slow suggesting base solubility and acidic reprecipitation as a method of purification of E-nitrolic acids.Deprotection of (Z)-O-acetylacetonitrolic acid by HO(1-) gives a highly reactive Z-nitrolic acid 17 which undergoes loss of NO2(1-) at a rate which precludes its detection; however the subsequent reactions of acetonitrile oxide (CH3CNO) formed were monitored.Rapid loss of NO2(1-) therefore occurs when there is assistance from an antiperiplanar lone pair on the imino nitrogen of the oximate anion.Arylnitrolic acids were also examined; these were in the E configuration 26 and therefore underwent slow loss of NO2(1-).Since NMR and IR data are unreliable for the assignment of configuration of nitrolic acids (relative to other oximes) a single crystal diffraction study was carried out on E-acetonitrolic acid 14.The large difference in reactivity observed for the E- and Z-nitrolic acids now permits strong supporting evidence for structural assignments.
