Tris(dipivaloylmethanato)europium-induced shifts of proton resonances in π-deficient nitrogen heterocycles was written by Armarego, W. L. F.;Batterham, T. J.;Kershaw, J. R.. And the article was included in Organic Magnetic Resonance in 1971.Product Details of 322-46-3 This article mentions the following:
Tris(dipivaloylmethanato)europium, [Eu(DPM)3], induced shifts of the PMR of pyridine and its 2-Me, 3-Me, 2,3-di-Me and 2,5-di-Me derivatives, pyridazine, pyrimidine, pyrazine, quinoline, isoquinoline, 1,6-, 1,7- and 1,8-naphthyridine, cinnoline, phthalazine, quinazoline, quinoxaline, 1,4,5- and 1,4,6-triazanaphthalene, pteridine, acridine, phenanthridine and 1,10-phenanthroline, were measured for solutions containing 0.1, 0.3, and 0.5 molar equivalents of Eu(DPM)3. Differences in the behavior of these heterocycles are discussed in terms of the steric relations between the heterocycle and the complex. The 3 cos2 * dhi term, present in the expression for calculating pseudocontact shifts, is important. The order of basicity of these heterocycles, as measured by their pKa values, cannot be used to predict the order of Eu(DPM)3 induced chem. shifts. In the experiment, the researchers used many compounds, for example, Pyrido[2,3-b]pyrazine (cas: 322-46-3Product Details of 322-46-3).
Pyrido[2,3-b]pyrazine (cas: 322-46-3) belongs to pyrazine derivatives. Pyrazines are volatile compounds that are used in the cosmetic, food, flavor, and fragrance industries. A number of pyrazine-based derivatives were used as dyes or fluorescent probes.Product Details of 322-46-3