Chemistry Reference
In-Depth Information
SCHEME 4.7.
Photolysis of anthranils and anthranilium salts.
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gave products, including incorporation of nonsolvent nucleophiles, similar to
those described earlier when irradiated in neutral aqueous or methanol solutions.
75
Photolysis of
in H
2
SO
4
also generates some reduction product 2-amino-5-
methylacetophenone, as does thermolysis of
25a
in H
2
SO
4
.
72
The authors suggested
that this product came from hydrogen abstraction by a triplet ion.
72
During the 1960s and 1970s research into carcinogenic aromatic amines estab-
lished that these species were precarcinogens that required activation.
12,76
A
common metabolic pathway was established (Scheme 4.8).
12,76
The end product,
a hydroxylamine or hydroxamic acid ester, regarded as the ultimate carcinogenic
metabolite, was shown to react predominately with guanine of the four DNA bases to
generate a C-8 adduct,
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.
77,78
The structure
31
31
led to speculation that the metabo-
lites undergo N
O bond heterolysis
in vivo
to generate nitrenium ions that are
responsible for the reactions with guanine in DNA.
12,76
The structure
is not the
expected product of the reaction of guanine with a cation via an S
N
1 mechanism.
31
