Question

The ^1H- and ^13C-NMR data for an unknown compound with molecular formula C_4H_4O_5 are shown below. Deduce a structural formula for this compound. ^1NMR: 4.46 (s, 2H), 11.0 (s, 2H). ^13C-NMR: 191.8,171.5,162.8, 37.2. You do not have to consider stereochemistry. You do not have to explicitly draw H atoms. In cases where there is more than one answer, just draw one.

Answer 1

Calculate the double bond equivalent (DBE) for the given structure is N H DBE -C+1 So, given compound may have 3 double bonds or 2double bonds and one ring From H-NMR Chemical shift 11.0 value represents the -COOH group. Chemical shift 4.4 value represents the methylene carbon. From 13C-NMR 191.8 Represents the keto (CO) group 171.5-162.8 represents the-COOH group 37.2 represent the methylene carbon From all the above information, the possible chemical structure is as follows но-с 2 OH

H-NMR spectrum: 12 10 PPM 13C-NMR Spectrum: 40 20 PPM