3.10 Carbonyl Compounds
71
3.10.4 Esters and Lactones
Assignment
Range
Comments
COOR
al C–(COOR)
al C–(OCOR)
165–180 ppm
20–70 ppm
50–100 ppm
Shift with respect to COOH -5 to -10 ppm
Shift with respect to C–(OH) +2 to +10 ppm
(C)=C–(COOR)
C=(C–COOR)
(C)=C–(OCOR)
C=(C–OCOR)
ar C–(COOR)
ar C–(OCOR)
ar C=(C–OCOR)
105–160 ppm
105–160 ppm
100–150 ppm
80–130 ppm
120–150 ppm
130–160 ppm
105–130 ppm
al CH–COOR
2.0–2.5 ppm
CH 3 COOR ≈2.0 ppm
CH 2 COOR ≈2.3 ppm
CHCOOR ≈2.5 ppm
al CH–OCOR
3.5–5.3 ppm
CH 3 OCOR ≈3.5–3.9 ppm
CH 2 COOR ≈4.0–4.5 ppm
CHCOOR ≈4.8–5.3 ppm
CH=CH–COOR
5.5–8.0 ppm
Shift with respect to CH=CH–H:
gem ≈+0.8 ppm, cis ≈+1.1 ppm
trans ≈+0.5 ppm
CH=CH–OCOR
6.0–8.0 ppm
Shift with respect to CH=CH–H:
gem ≈+2.1 ppm, cis ≈-0.4 ppm
trans ≈-0.6 ppm
ar CH–C–COOR 7.0–8.0 ppm
Shift with respect to CH–(C–H):
ortho ≈+0.7 ppm, meta ≈+0.1 ppm,
para ≈+0.2 ppm
ar CH–C–OCOR 6.8–7.5 ppm
Shift with respect to CH–(C–H):
ortho ≈-0.2 ppm, meta ≈0 ppm,
para ≈-0.1 ppm
C=O st
1745–1730 cm -1 Strong; range for aliphatic esters
Higher wavenumbers for hal–C–COOR,
COO–C=C, COO–C ar, and for small ring
lactones
Lower wavenumbers for C=C–COOR and
ar C–COOR
C–O st
1330–1050 cm -1 Mostly two bands, at least one of them
strong
For COO – , two bands: 1580 and 1420 cm -1
13 C
1 H
IR