Chemistry Reference
In-Depth Information
Nitrogen-containing compounds exhibit wide range of biological activities, therefore
introducing a nitrogen atom or group into a natural molecule moiety may result in
improvements to their biological activities. Substituted ureas have attracted great
attention because they possess various properties which make them suitable for
industrial, medical and agricultural applications. The synthesis and antitumour activity
of nitrogen derivatives of rosin acids have also been investigated. Rao and co-workers
[18] reported a series of novel unsymmetrically
N,N
′-substituted ureas (
19
-
22
) which
were synthesised from dehydroabietic acid through amide and isocyanate intermediates
(
Scheme 6.5
). Their cytotoxicity activities against SMMC-7721 cancer cells were
evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)
assay method. These compounds exhibited highly effective cytotoxicity activities
against SMMC-7721 cells. Their IC
50
values were between 8.8 and 14.2 μmol/L (see
Table 6.2
). The change of
N
′ substituted groups resulted in little difference to the
cytotoxicity activities of ureas, which indicating that the cytotoxicity of this kind of
ureas depends strongly on the tricyclic hydrophenanthrene structure.
Scheme 6.5
Structure of unsymmetrically
N,N
′-substituted ureas (
19
-
22
)
The antitumour activities of unsymmetrically disubstituted acylthioureas fused with
the hydrophenanthrene structure have been investigated (
Scheme 6.6
). A series of
novel unsymmetrically disubstituted acylthioureas fused with hydrophenanthrene
structure were synthesised from Δ
8
-dihydroabietic and dehydroabietic acid through
a chloride and acylisocyanate intermediate, respectively [19]. The antitumour
activities of these compounds against SMMC-7721 and A549 tumour cells were
evaluated by the MTT method. IC
50
data of three compounds against SMMC-7721
and A-549 cells are listed in
Table 6.3
. These three compounds (
23
-
25
) exhibited
highly effective activities against SMMC-7721 and A549 cells; their IC
50
values were
