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ACD/Labs Blog

Part 1 presented a challenge to determine an experiment to distinguish two very similar products from each other, namely 3-methyl-5-(pyridin-2-yloxy)pyridine and 5'-methyl-2H-1,3'-bipyridin-2-one. The products have identical formula weights and the LC/MS and 1H NMR are too similar to draw any conclusion from.   The first step is to determine what is different between the two...

In a previous blog, the atoms C, H, O, and N were limited to a specific range, 0-50, 0-100, 0-10 and 0-10, respectively. Starting from a wide atom count range ensures molecular formulae are not overlooked. The ranges for the atom count can be restricted further using additional information such as NMR, IR, etc. A...

As with many nitrogen-containing compounds, 15N chemical shift information can be critical in elucidating or confirming a candidate structure. Many elucidators extract 15N chemical shifts from such experiments as 15N NMR, 1H-15N HSQC or 1H-15N HMBC. Below are two tautomers, from a previous blog, that differ in the hybridization state of the nitrogen. The 15N...