Bioorganic & Medicinal Chemistry Letters 10 (2000) 1645±1648
Novel Inhibitors of AP-1 and NF-ꢀB Mediated Gene Expression:
Structure±Activity Relationship Studies of Ethyl 4-[(3-Methyl-
2,5-Dioxo(3-pyrrolinyl))amino]-2-(tri¯uoromethyl)pyrimidine-
5-carboxylate
Moorthy S. S. Palanki,* Paul E. Erdman, Anthony M. Manning, Arnold Ow,
Lynn J. Ransone, Cheryl Spooner, Carla Suto and Mark Suto
Signal Pharmaceuticals, Inc., 5555 Oberlin Drive, San Diego, CA 92121, USA
Received 16 March 2000; accepted 12 May 2000
AbstractÐIn an eort to identify novel inhibitors of AP-1 and NF-kB mediated transcriptional activation, several analogues of
ethyl 4-[(3-methyl-2,5-dioxo(3-pyrrolinyl))amino]-2-(tri¯uoromethyl)pyrimidine-5-carboxylate (1) were synthesized and tested in
two in vitro assays. The 2-(20-thienyl) substituted compound (11) was identi®ed as the most potent in this series. # 2000 Elsevier
Science Ltd. All rights reserved.
Introduction
eect on the production of IL-2 and IL-8 levels in stimu-
lated cells. Our goal was to improve potency by exploring
dierent substituents around the pyrimidine ring. We
introduced various groups on the pyrimidine ring at 2, 4
and 6-positions of 1. This paper describes the synthesis
and the structure±activity relationship of this series of
compounds.
There is now abundant evidence that T-lymphocytes
orchestrate both the initiation and propagation of
immune responses through the secretion of protein med-
iators termed cytokines.1 These cytokines play a very
important role in a number of in¯ammatory diseases.2,3
In allergies and autoimmune diseasesÐsuch as asthma,
psoriasis, rheumatoid arthritis, and transplant rejectionÐ
T-cell driven immune responses appear to overreact. In
activated T cells, transcription factors such as the activator
protein-1 (AP-1), regulate IL-2 production and produc-
tion of matrix metalloproteinases, while the nuclear fac-
tor-kB (NF-kB), is essential for the transcriptional
regulation of the proin¯ammatory cytokines IL-1, IL-6,
IL-8, and TNFa.4 Based on these observations, it appears
that inhibition of AP-1 and NF-kB transcriptional acti-
vation in T cells may represent an attractive target in the
development of novel antiin¯ammatory drugs (Fig. 1).5
Chemistry
The synthesis of 2- and 4-substituted analogues is shown
in Scheme 1. An appropriately substituted amidine was
cyclized with diethyl 2-(ethoxymethylene)propane-1,3-
dioate in ethanol and sodium ethoxide to give 4. The
amidines that are not available commercially were pre-
pared either from the corresponding nitrile or acid as
shown.6 The hydroxy group in 4 was converted to a chloro
group7 and then treated with hydrazine or methylhy-
drazine to give the appropriate intermediate, 5. Treatment
of the hydrazine intermediates (5) with appropriately
substituted maleic anhydride resulted in the ®nal products
(6±44). The treatment of 10 with acetic anhydride
resulted in 38. Table 1 shows the list of compounds that
were prepared with modi®cations at R1, R2, R3, and R4.
Using automated high-throughput assays with stably
transfected human jurkat T-cells, we identi®ed a com-
pound (1) from a diversity library that inhibited both AP-1
and NF-kB mediated transcriptional activation (IC50=1
mM) without blocking basal transcription driven by the
b-actin promoter. In addition, 1 had a similar inhibitory
We also examined the importance of the carboxylate
group at the 5-position. Several ester bioisosteres were
introduced in place of the ethyl ester of 11, which were
*Corresponding author. Tel.: +1-858-558-7500; fax: +1-858-623-
0870. e-mail: mpalanki@signalpharm.com
0960-894X/00/$ - see front matter # 2000 Elsevier Science Ltd. All rights reserved.
PII: S0960-894X(00)00312-7