Date post: | 31-Mar-2015 |
Category: |
Documents |
Upload: | frida-burnison |
View: | 479 times |
Download: | 22 times |
Aromatic Heterocyclic Compounds
Aromatic Five-Membered Heterocycles
Pyrrole is an extremely weak base
Pyrrole
Also aromatic, but lone pair of electrons is delocalized, so much weaker base.
=>
29 5-membered ring system
Other Heterocyclics
=>
NH
indole
Obenzofuran
S
benzothiophene
Other Heterocyclics
Aromatic Six-Membered-Ring Heterocycles
Pyridine
• Heterocyclic aromatic compound.• Nonbonding pair of electrons in sp2 orbital, so
weak base, pKb = 8.8.
=>
The pyridinium ion is a stronger acid than a typicalammonium ion
Quinoline and isoquinoline are known as benzopyridines
Some Biologically Important Heterocycles
Imidazole
Some Biologically Important Heterocycles
Basic or Nonbasic?
NNPyrimidine has two basicnitrogens.
N N H Imidazole has one basicnitrogen and one nonbasic.
N
N
N
N
H
Purine?=>
Chlorophyll a
Porphyrin
BILE PIGMENTS (bBILE PIGMENTS (bilirubin ilirubin and band biliverdin)iliverdin)
Bilirubin
H
Hem
Biliverdin
NNNN C C C OO
H3C C
CH2
H3C C H2C
CH2
COO-
C
C
CH3 C CH
CH2
H H
H
-OO
H2
H2 H3
H H H HH
B C D A
ADCB
H HHHHH
H3H2
H2
-OO
H
NNNN C C C OO
H3C C
CH2
H3C C H2C
CH2
COO-
C
C
CH3 C CH
CH2
Oxidat ion
Reduct ion
-Fe3+, -CO
Gallstones (bilirubin)Gallstones (bilirubin)
Collection of Pathological Department