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Cyanuric chloride can be sequentially reacted with the appro-
priate amines to furnish intermediate (22). The remaining halogen
can be displaced by hydrazine and condensed with the appropriate
aldehyde to furnish the desired hydrazone containing compounds.
An analogous route could be used to obtain (4). Bromoheterocycles
could be introduced by either the nucleophilic attack of nitrogen
heterocycles on dichloropyrimidine or by deprotonation of 2-chlo-
ropyrimidine and subsequent reaction with dibromoheterocycles
in the presence of DDQ. Subsequent reaction with morpholine fur-
nished intermediates (23) and (24). Installation of the 4-hydroxy-
3,5-dimethoxyphenyl motif was achieved using Suzuki coupling
reactions. An analogous route was used to furnish (5) and (13) Stir-
ring 2,4,6-trichloropyrimidine with morpholine resulted in reac-
tion in both the 2- and 4-positions. The remaining halogen could
be reacted with 2-furanboronic acid in a Suzuki coupling reaction
and the subsequent material brominated to furnish intermediate
(25). A variety of aryl groups were subsequently introduced using
Suzuki couplings. An analogous route was used to furnish (12).
In conclusion, we have identified a novel series of PIKK family
selective inhibitors of mTOR based on a hit found through a phar-
macophore analysis. The systematic optimisation of the molecules
has resulted in the identification of a number of extremely potent
and selective inhibitors of the enzyme mTOR kinase.
14. Lipinski, C. A.; Lombardo, F.; Dominy, B. W.; Feency, P. J. Adv. Drug Delivery Rev.
1997, 23, 3.
15. Inhibition of mTOR kinase was assayed using full-length mTOR (extracted from
HeLa cytoplasmic extract by immunoprecipitation) with a recombinant 4E-BP1
protein substrate and an ATP concentration of 50
lM. Detection of
phosphorylated product through an ELISA format was essentially as
described in Ref. 8 Figures quoted are the mean of at least 2 determinations
and variability around the mean was <50%.
16. mTOR Kinase inhibition experiments were conducted at increasing
concentrations of inhibitor (1) (50, 100, 200, 350, 500 nM) in varying
concentrations of ATP (10–100 lM). The data was plotted using a
Lineweaver-Burke double reciprocal plot and revealed characteristic
behaviour of competitive inhibition.
17. Verheijen, J. C.; Zask, A. Drugs Future 2007, 32, 537.
Acknowledgements
18. Hickson, I.; Zhao, Y.; Richardson, C. J.; Green, S. J.; Martin, N. M.; Orr, A. I.;
Reaper, P. M.; Jackson, S. P.; Curtin, N. J.; Smith, G. C. Cancer Res. 2004, 64, 9152.
19. Walker, E. H.; Pacold, M. E.; Perisic, O.; Stephens, L.; Hawkins, P. T.; Wymann,
M. P.; Williams, R. L. Mol. Cell. 2000, 6, 909.
The authors would like to thank Dr Lisa Smith and Mrs Sharon
Maguire for their help in producing the biological data presented.
20. Monolayers of MDCKII (Madin Darby Canine Kidney Cells) cells transfected
with the human MDR1 (Multi-Drug Resistance 1) transporter protein were
cultured in transwells and used to study the permeability and efflux potential
References and notes
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