2-Pyridone

2-Pyridone is an organic compound with the formula C
5H
4NH(O). This colourless crystalline solid is used in peptide synthesis. It is well known to form hydrogen bonded structures somewhat related to the base-pairing mechanism found in RNA and DNA. It is also a classic case of a molecule that exists as tautomers.

Structure

The most prominent feature of 2-pyridone is the amide group; a nitrogen with a hydrogen bound to it and a keto group next to it. In peptides, amino acids are linked by this pattern, a feature responsible for some remarkable physical and chemical properties. In this and similar molecules, the hydrogen bound to the nitrogen is suitable to form strong hydrogen bonds to other nitrogen- and oxygen-containing species.

Tautomerism

The hydrogen attached to the nitrogen can also move to the oxygen. Through movement of this hydrogen and electrons, the second tautomer form, 2-hydroxypyridine is formed. This lactam lactim tautomerism can also be found in other molecules with a similar structure.

2-Pyridone (data page)

This page provides supplementary chemical data on 2-pyridone.

Analytical data

NMR spectroscopy

¹H-NMR

¹H-NMR (400 MHz, CD₃OD): /ρ = 8.07 (dd,³J = 2.5 Hz,⁴J = 1.1 Hz, 1H, C-6), 7.98 (dd,³J = 4.0 Hz,³J = 2.0 Hz, 1H, C-3), 7.23 (dd,³J = 2.5 Hz,³J = 2.0 Hz, 1H, C-5), 7.21 (dd,³J = 4.0 Hz,⁴J = 1.0 Hz, 1H, C-4).

¹³C-NMR

(100.57 MHz, CD₃OD): ρ = 155.9 (C-2), 140.8 (C-4), 138.3 (C-6), 125.8 (C-3), 124.4 (C-5)

UV/Vis spectroscopy

(MeOH):ν_max (lg ε) = 226.2 (0.44), 297.6 (0.30).

IR spectroscopy

(KBr): ν = 3440 cm⁻¹–1 (br, m), 3119 (m), 3072 (m), 2986 (m), 1682 (s), 1649 (vs), 1609 (vs), 1578 (vs), 1540 (s), 1456 (m), 1433 (m), 1364 (w), 1243 (m), 1156 (m), 1098 (m), 983 (m), 926 (w), 781 (s), 730 (w), 612 (w), 560 (w), 554 (w), 526 (m), 476 (m), 451 (w).

Mass spectrometry

EI-MS (70 eV): m/z (%) = 95 (100) [M⁺], 67 (35) [M⁺ - CO], 51 (4)[C₄H₃⁺].

References