N
X
C
Hal
O
N
S
P Si
Natural
Products
Solvents
C
C
C
C C
C
8.11 Carbonyl Compounds
429
8.11.7 Imides
Saturated acyclic imides: Consecutive CO (Δm 28) and alkoxy elimination:
N
O
O
N
O
C N
m /z 56
+
– CO
– CH 3 O
.
+ .
+ .
Ketene elimination:
N
O
O
N
O
H
O H C N
m/z 58
+
– CH 2 CO
– CH 3
.
H
+ .
+ .
If the N-substituent chain is sufficiently long, cleavage of the C–C bonds next to N,
with or without H rearrangement.
Dibenzoylamine: Loss of CO to N-phenylbenzamide:
N
O
H
O
– CO
N
O
H
– C 6 H 5 N H
.
C
O
m/z 105
+
+ .
+ .
Cyclic imides: The spectra of saturated cyclic imides are almost identical to those of
the corresponding diketones. Loss of HNCO (Δm 43) from succinimide, followed
by CO elimination (Δm 28). Aroyl migration and loss of CO 2 from aromatic cyclic
imides.
N
O
O
R
O
O
NR
[M –44]
+ .
– CO 2
+ .
+ .