Highly potent dipeptidyl peptidase IV inhibitors derived from Alogliptin through pharmacophore hybridization and lead optimization

Article abstract of DOI:10.1016/j.ejmech.2013.08.010

The superposition of the DPP-IV complex revealed that the butynyl group of Linagliptin can be freely switched with the cyanobenzyl group of Alogliptin. Thus, a pharmacophore hybridization of Alogliptin was initiated and led to a novel DPP-IV inhibitor, 11a. Although it did not exhibit the desired activity (IC₅₀ = 0.2 μM), compound 11a acts as a lead compound, which triggered a resulting structural optimization and the formation of compound 11m. A novel series of potent DPP-IV inhibitors represented by compound 11m (IC ₅₀ = 0.4 nM) was ultimately obtained with a robust pharmacokinetic profile and superior in vitro and in vivo efficacy compared to Alogliptin.

Full text of DOI:10.1016/j.ejmech.2013.08.010

European Journal of Medicinal Chemistry 68 (2013) 312e320
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Highly potent dipeptidyl peptidase IV inhibitors derived from
Alogliptin through pharmacophore hybridization and lead
optimization
Hui Xie a, Lili Zeng b, Shaogao Zeng b, Xin Lu b, Xin Zhao b, Guicheng Zhang b,
,
Zhengchao Tu b, Hongjiang Xu c, Ling Yang c, Xiquan Zhang c, Shanchun Wang c
,
**
,
Wenhui Hu b
*
a First Affiliated Hospital of Guangzhou Medical University, 151 Yanjiang Road, Guangzhou 510120, China
b Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Science, 190 Kaiyuan Avenue, Guangzhou Science Park, Guangzhou 510530, China
c Jiangsu Chia-Tai Tianqing Pharmaceutical Co. Ltd, No. 8 Julong North Rd., Xinpu, Lianyungang, Jiangsu 222006, China
a r t i c l e i n f o
a b s t r a c t
Article history:
The superposition of the DPP-IV complex revealed that the butynyl group of Linagliptin can be freely
switched with the cyanobenzyl group of Alogliptin. Thus, a pharmacophore hybridization of Alogliptin
was initiated and led to a novel DPP-IV inhibitor, 11a. Although it did not exhibit the desired activity
Received 8 July 2013
Received in revised form
2 August 2013
Accepted 3 August 2013
Available online 13 August 2013
(IC50 ¼ 0.2
mM), compound 11a acts as a lead compound, which triggered a resulting structural opti-
mization and the formation of compound 11m. A novel series of potent DPP-IV inhibitors represented by
compound 11m (IC50 ¼ 0.4 nM) was ultimately obtained with a robust pharmacokinetic profile and
superior in vitro and in vivo efficacy compared to Alogliptin.
Keywords:
Ó 2013 Elsevier Masson SAS. All rights reserved.
DPP-IV inhibitor
Type 2 diabetes
Superposition
Pharmacophore hybridization
In vivo
1. Introduction
load [2]. Unlike other incretin hormones, GLP-1 exhibits glucose
regulatory actions in diabetes patients. Bioactive GLP-1 has dis-
Diabetes mellitus is a group of metabolic diseases characterized
by hyperglycemia that affects more than 371 million people
worldwide. Type 2 diabetes (T2D, formerly referred to as non-
insulin-dependent or adult-onset diabetes) results from an insuf-
ficient response to insulin by the body and comprises over 90% of
diabetes patients. Undiagnosed T2D combined with corresponding
multisystem complications causes disability of patients and brings
with great social burden. Nonetheless, traditional T2D treatments
are usually associated with undesired side effects, such as hypo-
glycemia, edema, and weight gain. Thus, more persistent efforts
should be made to meet the medical needs of this disease [1].
Glucagon like peptide-1 (GLP-1) is one of the important incretin
hormones that stimulate insulin release after an enteric glucose
played multiple functions, such as an increase in insulin secretion
and sensitivity, stimulation of cell mass, and reduction of
b
glucagon secretion [3]. Further understanding of the GLP-1 inacti-
vation process revealed the essential role of dipeptidyl peptidase IV
(DPP-IV) and contributed to the development of DPP-IV inhibitors.
Orally bioavailable DPP-IV inhibitors can retain the biological
function of GLP-1 by blocking DPP-IV truncation of bioactive GLP-1
[4e6]. Thus, these orally effective inhibitors gradually became the
major intervention for type 2 diabetics and are represented by the
following marketed drugs: Sitagliptin 1 [7,8], Vildaglipin 2 [9e11],
Saxagliptin 3 [12], Alogliptin 4 [13], Linagliptin 5 [14], Gemigliptin 6
[15], and Teneligliptin 7 [16] (Fig. 1).
Previously, we identified several series of DPP-IV inhibitors
derived from Alogliptin using multiple classic medicinal chemistry
strategies [17e19]. Inspired by the approval of Linagliptin and both
its superior potency and longer duration of action in comparison to
the other marketed drugs [20], we carefully compared the binding
mode of Linagliptin in the DPP-IV enzyme to that of Alogliptin.
* Corresponding author. Tel.: þ86 020 32015211; fax: þ86 020 32015 299.
** Corresponding author. Tel.: þ86 0518 85685887.
E-mail addresses: wangshanchun@cttq.com (S. Wang), hu_wenhui@gibh.ac.cn
(W. Hu).
0223-5234/$ e see front matter Ó 2013 Elsevier Masson SAS. All rights reserved.
http://dx.doi.org/10.1016/j.ejmech.2013.08.010

H. Xie et al. / European Journal of Medicinal Chemistry 68 (2013) 312e320
313
Fig. 1. Marketed DPP-IV inhibitors.
The similarity of the two molecules prompted us to note that the
cyanobenzyl group of Alogliptin could be replaced with the butynyl
group of Linagliptin. Herein, we reported how we rapidly generated
a new lead compound (11a, IC50 ¼ 198 nM) by pharmacophore
hybridization and then generated highly potent DPP-IV inhibitors
from structural optimization. Compound 11m (IC50 ¼ 0.4 nM) was
ultimately obtained with a robust pharmacokinetic profile and
better in vitro and in vivo efficacy than Alogliptin.
butynyl and cyanobenzyl can be freely switched between Alogliptin
and Linagliptin.
3.2. Generation of lead compound 11a
We previously synthesized several series of DPP-IV inhibitors
solely based on Alogliptin through the scaffold hopping strategy
[17]. In this study, we kept the scaffold of Alogliptin constant and
replaced the cyanobenzyl group with the butynyl group to imme-
diately generate a novel compound, 11a (Fig. 3). To our disap-
pointment, compound 11a did not exert the desired in vitro DPP-IV
inhibitory activity (IC50 ¼ 198 nM). However, encouraged by our
previous successful experience of lead optimization of the DPP-IV
inhibitor, compound 11a was put forward for structural optimiza-
tion towards the discovery of highly potent DPP-IV inhibitors.
2. Chemistry
The synthesis of compounds 11aeo is outlined in Scheme 1.
Generally, the alkylation of commercially available material 8 with
1-bromo-2-butyne produced precursor 9. Compounds 10aeo were
obtained by the N-alkylation of compound 9. The final compounds
11aeo were obtained by the replacement of the chloro group with a
3-(R)-amino-piperidinyl group.
3.3. N-3 position variations on compound 11a
3. Results and discussion
The crystal complex of Linagliptin and Alogliptin also suggests
that there is a large space at the N-3 position of Alogliptin. Thus, a
substitution variation at the N-3 position of compound 11a was
conducted and generated some of the DPP-IV inhibitors listed in
Table 1. Although the butynyl group is a very important part of the
pharmacophore, it (compound 11b) did not exert activity as a
functional group at the N-3 position. The replacement of benzyl 11c
at N-3 also led to the loss of activity. The addition of heterocyclic
rings (compounds 11deg) immediately resulted in good activity
and important selectivity over DPP-8/9 [21e23]. These data suggest
that N-3 methylheteroaromatic group could improve DPP-IV ac-
tivity and selectivity due to hydrogen bond effect.
3.1. Computational comparison of the binding modes of Alogliptin
and Linagliptin
Both Alogliptin and Linagliptin have the same 3-(R)-amino-
piperidinyl as their functional group, yet Linagliptin is more potent
than Alogliptin and other DPP-IV inhibitors on the drug market. We
superimposed the crystal structures of the DPP-4 complex with
Alogliptin [13] and Linagliptin [20] in Discovery Studio 3.0 (Accel-
rys, San Diego, CA). The superposition (Fig. 2) revealed that both 3-
(R)-amino-piperidinyl groups interact with E205 and E206. In
addition, the butynyl of Linagliptin and the cyanobenzyl of Alog-
liptin occupy the same S1 pocket of the DPP-IV enzyme. Thus, the
structural superposition indicates that the two functional groups
Compound 11f has an IC50 value of 3.1 nM and good pharma-
cokinetic properties with 63% oral bioavailability as well as 4.2 h of
oral half-life in male Sprague Dawley (SD) rats. However, 11f
Scheme 1. Synthesis of compounds 11aeo. Reagents: (a) 1-bromo-2-butyne, DIEA, DMF, rt; (b) RX (X ¼ Cl, Br, I), NaH, LiBr, DMF; (c) 3-(R)-aminopiperidine, NaHCO3, 120 ꢀC,
NaHCO3, EtOH.

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H. Xie et al. / European Journal of Medicinal Chemistry 68 (2013) 312e320
Fig. 2. Structural superposition of crystal structures of DPP-IV binding Alogliptin (PDB ID. 3G0B, blue and yellow) and Linagliptin (PDB ID. 2RGU, gray and red). (For interpretation of
the references to color in this figure legend, the reader is referred to the web version of this article.)
exhibits little inhibition on cytochrome P450 3A (IC50 ¼ 97.9
which may suggest a lower drugedrug interaction risk.
m
M),
In regard to its in vivo evaluations, compound 11m showed
73.3% oral bioavailability and over 5 h of half-life (Table 3, Fig. 5). In
a 24 h in vivo DPP-IV activity test in ICR mice, 11m displayed
stronger and longer inhibition of DPP-IV than Alogliptin at 1 mg/kg
and 3 mg/kg (Fig. 6). The corresponding inhibition rates, listed in
Table 4, were calculated and were consistent with the in vitro ac-
tivity and in vivo half-life between Alogliptin and compound 11m
(Alogliptin: IC50 ¼ 1.5 nM, T1/2 ¼ 2 h; 11m: IC50 ¼ 0.4 nM, T1/2 ¼ 5 h).
3.4. Further optimization of compound 11f
Although compound 11f exhibited the desired in vitro activity,
selectivity and other related properties, we were still curious about
its further optimization. Eight close analogs (11heo, Table 2) of
compound 11f substituted on the quinoline ring were synthesized
and screened. All of the compounds exhibited good activity and
selectivity against DPP-IV, DPP-8/9 and CYP 3A. The analysis of the
6-halogen compounds 11hej demonstrated a good activity trend
for bromo, chloro and fluoro as 6-substituents, which indicated that
larger substituents are not suitable for this position. The effect of
chloro substitution at the 6 (11i), 7 (11m), and 4 (11o) positions was
closely compared and revealed that the 7 position is among the
best. Thus we introduced 7-chloro group (compound 11m) while
keeping position 4 and 6 unsubstituted. Finally, compound 11m
was found to be the most active inhibitor in Table 2 and selected for
further studies, since 7-fluroroquinolinylmethyl compound 11n did
not display a higher in vitro potency.
4. Conclusion
The accumulation of DPP-IV inhibitors as market drugs provides
more elaborate information for drug design with classic medicinal
strategies. The similarity of the binding modes of Alogliptin and
Linagliptin prompted us to conduct a molecular operation between
the two market drugs with pharmacophore hybridization and
structural optimization. The replacement of the cyanobenzyl group
of Alogliptin with the butynyl group of Linagliptin immediately
generated the novel compound 11a (IC50 ¼ 198 nM) as a lead, which
Table 1
DPP inhibitory profiles of compounds 11beg.
3.5. Pharmacological evaluations of compound 11m
As described above, compound 11m exhibits good activity and
selectivity against DPP-IV (Table 2) and has a low risk of drugedrug
interaction and heart QT interval prolongation with an IC50 value of
46.2
mM against CYP 3A and of over 100 mM against hERG. We
No.
R
IC50
conducted molecular docking to simulate the potential binding
sites of DPP-IV by Discovery Studio 3.0 (Accelrys, San Diego, CA,
Fig. 4). Compound 11m (IC50 ¼ 0.4 nM) interacts with serine 630
and glutamic acid 205, 206, which is much like the binding mode of
Alogliptin and Linagliptin. This similarity of the binding mode
revealed the feasibility of rapid generation of drug-like derivatives
through molecular operation based on market drugs.
DPP-IV (nM)
DPP-8 (
>100
mM)
DPP-9 (
>100
mM)
11b
11c
2177.5
>10,000
>100
>100
11d
11e
3.4
>100
>100
>100
>100
22.0
11f
3.1
>100
>100
>100
>100
11g
31.3
Data represent means of at least two independent experiments.
Fig. 3. Generation of 11a by pharmacophore hybridization strategy.

H. Xie et al. / European Journal of Medicinal Chemistry 68 (2013) 312e320
315
Table 2
Table 3
Inhibitory profiles of compounds 11heo.
Selected pharmacokinetic parameters for compound 11m in male Sprague Dawley
rats.
Dose
(mg/kg)
i.v./p.o.
Iv T1/2 (h)
Oral T1/2
(h)
poAUC0et
g h mLꢃ1
CLp
VZ/F
F%
(
m
)
(L hꢃ1 kgꢃ1
)
(L kgꢃ1
)
5/25
5.65 ꢂ 1.13 5.02 ꢂ 1.39 17.58 ꢂ 2.82 1.05 ꢂ 0.15 8.65 ꢂ 2.43 73
No.
R
IC50
i.v., intravenous injection; p.o. oral administration.
DPP-IV
(nM)
DPP-8
M)
DPP-9
M)
CYP 3A
(mM)
(
m
(
m
visually under ultraviolet irradiation (254 nm) and by spraying
with an ethanol solution of 2,4-DNP or ninhydrin or by fuming with
an iodine steam. Silica gel column chromatography was performed
on silica gel (200e300 mesh) from Qing Dao Hai Yang. NMR spectra
were recorded on a Bruker NMR AVANCE 400 (400 MHz) or a
11h
11i
11j
10.8
6.6
>100
>100
>100
>100
>100
>100
79.36 ꢂ 14.78
91.93 ꢂ 30.21
58.28 ꢂ 9.47
2.0
Bruker NMR AVANCE 500 (500 MHz). Chemical shifts (d) were
recorded in ppm and coupling constants (J) in hertz (Hz). Splitting
patterns describe apparent multiplicities and are designated as s
(singlet), d (doublet), t (triplet), q (quartet), m (multiplet) or br
(broad). MS data were measured on an Agilent MSD-1200 ESI-MS
system.
11k
11l
9.1
1.9
>100
>100
>100
>100
46.24 ꢂ 8.07
42.19 ꢂ 6.19
11m
11n
11o
0.4
0.7
1.2
>100
>100
>100
>100
>100
46.18 ꢂ 6.80
54.65 ꢂ 7.25
14.08 ꢂ 1.95
5.1.1. 1-(But-2-yn-1-yl)-6-chloropyrimidine-2,4(1H,3H)-dione (9)
1-Bromo-2-butyne (9.4 mL, 0.11 mol) was added to a mixture of
6-chloropyrimidine-2,4(1H,3H)-dione (14.6 g, 0.1 mol), ethyl-
diisopropylamine (15 mL, 0.15 mol) and 250 mL of N,N-dime-
thylformamide. The reaction mixture was stirred overnight at
ambient temperature. For work-up, the reaction mixture was
diluted with approximately 300 mL of water. The light precipitate
formed was suction filtered and washed with water. The filter cake
was washed with diethyl ether and dried to give 1-(but-2-yn-1-yl)-
6-chloropyrimidine-2,4(1H,3H)-dione (9) as a yellow powder (17 g,
84.5
Alogliptin
1.5
>30 [13]
Data represent nominalized means of at least two independent experiments.
triggered a further structural modification. Variations on the N-3
position of compound 11a resulted in a series of novel DPP-IV in-
hibitors with activity in the nanomolar range. The most potent
inhibitor, 11m (IC50 ¼ 0.4 nM, F ¼ 77%, T1/2 ¼ 5 h), was proven to
bear a better and longer duration of in vivo DPP-IV activity than
Alogliptin. This study demonstrated that the employment of classic
medicinal chemistry strategies on marketed type 2 diabetes drugs
is an efficient way to generate novel DPP-IV inhibitors.
yield 85%). 1H NMR (400 MHz, CDCl3)
d 5.91 (s, 1H), 4.75 (d,
J ¼ 2.0 Hz, 2H), 1.82 (t, J ¼ 2.0 Hz, 3H). ESI-MS calculated for
(C8H8ClN2O2) [M þ H]þ, 199.03, found 199.0.
5.1.2. 1-(But-2-yn-1-yl)-6-chloro-3-methylpyrimidine-2,4(1H,3H)-
dione (10a)
A mixture of 9 (500 mg, 2.5 mmol) and 5 mL of DMF was added
to NaH (60% in oil, 2e q) at 0 ꢀC and LiBr (3 eq) after being stirred for
5 min. The reaction mixture was subsequently cooled to 0 ꢀC after
being stirred for 20 min, and CH3I (900 mg, 6.2 mmol) was added at
5. Experimental section
0
ꢀC. The reaction mixture was stirred overnight at room temper-
5.1. Chemistry
ature. The mixture was poured into 50 mL of water and extracted
with ethyl acetate. The combined organic layers were washed with
water and brine and dried over magnesium sulfate. After filtration,
the solvent was removed, and the crude residue was purified by
silica gel column chromatography to give 525 mg (98%) of the title
All commercially available compounds and solvents were of
reagent grade and were used without further treatment unless
otherwise noted. Reactions were monitored by TLC using Qing Dao
Hai Yang GF254 silica gel plates (5 ꢁ 10 cm); zones were detected
Fig. 5. Concentration-time curve of compound 11m in a pharmacokinetic study in SD
Fig. 4. Molecular docking of 11m and DPP-IV enzyme (PDB ID. 3G0B).
rats.

316
H. Xie et al. / European Journal of Medicinal Chemistry 68 (2013) 312e320
5.1.7. 1-(But-2-yn-1-yl)-6-chloro-3-(quinolin-2-ylmethyl)
pyrimidine-2,4(1H,3H)-dione (10f)
The title compound was prepared from 2-(chloromethyl)quin-
oline in 23.9% yield according to the procedure for example 10a. 1H
NMR (400 MHz, CDCl3)
d
8.10 (d, J ¼ 8.4 Hz, 1H), 8.00 (d, J ¼ 8.4 Hz,
1H), 7.77 (d, J ¼ 8.4 Hz, 1H), 7.67e7.63 (m, 1H), 7.50e7.46 (m, 1H),
7.32 (d, J ¼ 8.4 Hz, 1H), 6.05 (s, 1H), 5.43 (s, 2H), 4.82e4.80 (m, 2H),
1.82 (t, J ¼ 2.4 Hz, 3H). ESI-MS calculated for (C18H15ClN3O2)
[M þ H]þ, 340.08, found 340.1.
5.1.8. 3-(Benzo[f]quinolin-3-ylmethyl)-1-(but-2-yn-1-yl)-6-
chloropyrimidine-2,4(1H,3H)-dione (10g)
The title compound was prepared from 3-(chloromethyl)benzo
[f]quinoline in 33.1% yield according to the procedure for example
Fig. 6. Effect of oral administration of compound 11m and Alogliptin on plasma DPP-IV
in ICR mice at 1, 3 mg/kg.
10a. 1H NMR (400 MHz, CDCl3)
d
8.89 (d, J ¼ 8.8 Hz, 1H), 8.58 (d,
J ¼ 8.0 Hz, 1H), 7.95e7.90 (m, 3H), 7.69e7.60 (m, 2H), 7.49 (d,
J ¼ 8.4 Hz, 1H), 6.06 (s, 1H), 5.48 (s, 2H), 4.81 (d, J ¼ 2.4 Hz, 2H), 1.83
(t, J ¼ 2.4 Hz, 3H). ESI-MS calculated for (C22H17ClN3O2) [M þ H]þ,
390.10, found 390.1.
compound. 1H NMR (400 MHz, CDCl3)
d 5.94 (s, 1H), 4.77 (d,
J ¼ 2.4 Hz, 2H), 3.33 (s, 3H), 1.81e1.80 (t, J ¼ 2.4 Hz, 3H). ESI-MS
calculated for (C9H10ClN2O2) [M þ H]þ, 213.04, found 213.0.
5.1.9. 3-((6-Bromoquinolin-2-yl)methyl)-1-(but-2-yn-1-yl)-6-
chloropyrimidine-2,4(1H,3H)-dione (10h)
The title compound was prepared from 6-bromo-2-(chlor-
omethyl)quinoline in 32.4% yield according to the procedure for
5.1.3. (R)-6-(3-Aminopiperidin-1-yl)-1,3-di(but-2-yn-1-yl)
pyrimidine-2,4(1H,3H)-dione (10b)
The title compound was prepared from 1-bromobut-2-yne in
90.0% yield according to the procedure for example 10a. 1H NMR
example 10a. 1H NMR (400 MHz, CDCl3)
d
8.01 (d, J ¼ 8.8 Hz, 1H),
(400 MHz, CDCl3)
d
5.96 (s, 1H), 4.80e4.78 (q, J ¼ 2.4 Hz, 2H), 4.64e
7.93 (d, J ¼ 2.0 Hz, 1H), 7.86 (d, J ¼ 8.8 Hz, 1H), 7.72e7.69 (m, 1H),
7.34 (d, J ¼ 8.4 Hz, 1H), 6.05 (s, 1H), 5.40 (s, 2H), 4.81e4.80 (m, 2H),
1.82 (t, J ¼ 2.4 Hz, 3H). ESI-MS calculated for (C18H14BrClN3O2)
[M þ H]þ, 418.00,419.99, found 419.0, 421.00.
4.62 (q, J ¼ 2.4 Hz, 2H), 1.82e1.81 (t, J ¼ 2.4 Hz, 3H), 1.78e1.77 (t,
J ¼ 2.4 Hz, 3H). ESI-MS calculated for (C12H12ClN2O2) [M þ H]þ,
251.06, found 251.0.
5.1.4. 3-Benzyl-1-(but-2-yn-1-yl)-6-chloropyrimidine-2,4(1H,3H)-
dione (10c)
5.1.10. 1-(But-2-yn-1-yl)-6-chloro-3-((6-chloroquinolin-2-yl)
methyl)pyrimidine-2,4(1H,3H)-dione (10i)
The title compound was prepared from 6-chloro-2-(chlor-
omethyl)quinoline in 53.7% yield according to the procedure for
The title compound was prepared from (bromomethyl)benzene
in 76.0% yield according to the procedure for example 10a. 1H NMR
(400 MHz, CDCl3)
d 7.40e7.38 (m, 2H), 7.26e7.14 (m, 3H), 5.86 (s,
example 10a. 1H NMR (400 MHz, CDCl3)
d
8.00 (d, J ¼ 8.4 Hz, 1H),
1H), 4.99 (s, 2H), 4.65e4.64 (d, J ¼ 2.4 Hz, 2H), 1.73e1.72 (t,
J ¼ 2.4 Hz, 3H). ESI-MS calculated for (C15H14ClN2O2) [M þ H]þ,
289.07, found 289.1.
7.92 (d, J ¼ 8.8 Hz, 1H), 7.74 (d, J ¼ 2.4 Hz, 1H), 7.58e7.56 (m, 1H),
7.34 (d, J ¼ 8.4 Hz, 1H), 6.04 (s, 1H), 5.40 (s, 2H), 4.81e4.79 (m, 2H),
1.82 (t, J ¼ 2.4 Hz, 3H). ESI-MS calculated for (C18H14Cl2N3O2)
[M þ H]þ, 374.05, 376.04, found 374.0, 376.0.
5.1.5. 1-(But-2-yn-1-yl)-6-chloro-3-(pyrimidin-2-ylmethyl)
pyrimidine-2,4(1H,3H)-dione (10d)
5.1.11. 1-(But-2-yn-1-(but-2-yn-1-yl))-6-chloro-3-((6-
The title compound was prepared from 2-(chloromethyl)py-
rimidine in 71.0% yield according to the procedure for example 10a.
fluoroquinolin-2-yl)methyl)pyrimidine-2,4(1H,3H)-dione (10j)
The title compound was prepared from 2-(chloromethyl)-6-
fluoroquinoline in 58.9% yield according to the procedure for
1H NMR (400 MHz, CDCl3)
J ¼ 4.8 Hz, 1H), 5.94 (s, 1H), 5.28 (s, 2H), 4.72e4.71 (m, 2H), 1.73 (t,
J ¼ 2.4 Hz, 3H). ESI-MS calculated for (C13H12ClN4O2) [M þ H]þ,
291.06, found 291.0.
d
8.56 (d, J ¼ 4.8 Hz, 2H), 7.09 (t,
example 10a. 1H NMR (400 MHz, CDCl3)
d
8.04 (d, J ¼ 8.4 Hz, 1H),
7.99 (dd, J ¼ 5.2 Hz, 1H), 7.44e7.34 (m, 3H), 6.05 (s, 1H), 5.41 (s, 2H),
4.82e4.80 (m, 2H), 1.82 (t, J ¼ 2.0 Hz, 3H). ESI-MS calculated for
(C18H14ClFN3O2) [M þ H]þ, 358.08, found 358.1.
5.1.6. 3-((1H-Benzo[d]imidazol-2-yl)methyl)-1-(but-2-yn-1-yl)-6-
chloropyrimidine-2,4(1H,3H)-dione (10e)
5.1.12. 1-(But-2-yn-1-yl)-6-chloro-3-((6-methylquinolin-2-yl)
methyl)pyrimidine-2,4(1H,3H)-dione (10k)
The title compound was prepared from 2-(chloromethyl)-6-
methylquinoline in 51.9% yield according to the procedure for
The title compound was prepared from 2-(chloromethyl)-1H-
benzo[d]imidazole in 27.6% yield according to the procedure for
example 10a. 1H NMR (400 MHz, CDCl3)
d 7.59e7.56 (m, 2H), 7.24e
7.21 (m, 2H), 5.89 (s, 1H), 5.40 (s, 2H), 4.75 (d, J ¼ 2.4 Hz, 2H), 1.79 (t,
J ¼ 2.4 Hz, 3H). ESI-MS calculated for (C16H14ClN4O2) [M þ H]þ,
329.08, found 329.1.
example 10a. 1H NMR (400 MHz, CDCl3)
d
8.01 (d, J ¼ 8.4 Hz, 1H),
7.95 (d, J ¼ 8.8 Hz, 1H), 7.87 (d, J ¼ 1.6 Hz, 1H), 7.80e7.77 (m, 1H),
7.26 (d, J ¼ 8.4 Hz, 1H), 5.99 (s, 1H), 5.25 (s, 2H), 4.77e4.75 (m, 2H),
2.72 (s, 3H), 1.80 (t, J ¼ 2.4 Hz, 3H). ESI-MS calculated for
(C19H17ClN3O2) [M þ H]þ, 354.10, found 354.1.
Table 4
DPP-IV inhibition of compound 11m in ICR mice.
Dose
DPP-IV inhibition
5.1.13. 1-(But-2-yn-1-yl)-6-chloro-3-((6-methoxyquinolin-2-yl)
methyl)pyrimidine-2,4(1H,3H)-dione (10l)
mg/kg
0.5 h
4.5 h
7 h
24 h
Alogliptin
3
1
3
1
83.8%
72.6%
80.4%
51.8%
71.5%
49.4%
84.7%
76.0%
50.9%
27.6%
82.3%
71.6%
0.8%
0.5%
13.5%
11.5%
The title compound was prepared from 2-(chloromethyl)-6-
methoxyquinoline in 55.1% yield according to the procedure for
11m
example 10a. 1H NMR (400 MHz, CDCl3)
d
7.98 (d, J ¼ 8.4 Hz, 1H),
7.90 (d, J ¼ 9.2 Hz, 1H), 7.31e7.27 (m, 2H), 7.03 (d, J ¼ 2.8 Hz, 1H),

H. Xie et al. / European Journal of Medicinal Chemistry 68 (2013) 312e320
317
6.04 (s, 1H), 5.39 (s, 2H), 4.81e4.79 (m, 2H), 3.90 (s, 3H), 1.82 (t,
J ¼ 2.4 Hz, 3H). ESI-MS calculated for (C19H17ClN3O3) [M þ H]þ,
370.10, found 370.1.
according to the procedure for example 11a. 1H NMR (400 MHz,
MeOD) 7.35e7.31 (m, 2H), 7.29e7.22 (m, 3H), 5.30 (s, 1H), 5.07 (s,
2H), 4.56 (t, J ¼ 18.4 Hz, 2H), 3.37e3.33 (m, 2H), 2.96e2.93 (m, 1H),
2.81e2.73 (m, 1H), 2.57e2.52 (m, 1H), 2.02e1.99 (m, 1H), 1.89e1.86
(m, 1H), 1.81 (s, 3H), 1.76e1.71 (m, 1H), 1.38e1.31 (m, 1H); 13C NMR
d
5.1.14. 1-(But-2-yn-1-yl)-6-chloro-3-((7-chloroquinolin-2-yl)
methyl)pyrimidine-2,4(1H,3H)-dione (10m)
(125 MHz, MeOD)
d 165.10, 161.72, 153.66, 138.42, 129.35(2C),
The title compound was prepared from 7-chloro-2-(chlor-
omethyl)quinoline in 58.8% yield according to the procedure for
129.15(2C), 128.41, 89.37, 81.10, 74.71, 59.36, 52.75, 48.45, 45.22,
36.83, 33.45, 24.31, 3.06. ESI-MS calculated for (C20H25N4O2)
[M þ H]þ, 353.20, found 353.2.
example 10a. 1H NMR (400 MHz, CDCl3)
d
8.06 (d, J ¼ 8.4 Hz, 1H),
8.00 (s, 1H), 7.69 (d, J ¼ 8.8 Hz, 1H), 7.43e7.41 (m, 1H), 7.32 (d,
J ¼ 8.4 Hz, 1H), 6.04 (s, 1H), 5.40 (s, 2H), 4.81e4.80 (m, 2H), 1.83 (t,
J ¼ 2.4 Hz, 3H). ESI-MS calculated for (C18H14Cl2N3O2) [M þ H]þ,
374.05, 376.04, found 374.0, 376.0.
5.1.20. (R)-6-(3-Aminopiperidin-1-yl)-1-(but-2-yn-1-yl)-3-
(pyrimidin-2-ylmethyl)pyrimidine-2,4(1H,3H)-dione (11d)
The title compound was prepared from 1-(but-2-yn-1-yl)-6-
chloro-3-(pyrimidin-2-ylmethyl)pyrimidine-2,4(1H,3H)-dione
(10d) in 69.4% yield according to the procedure for example 11a. 1H
5.1.15. 1-(But-2-yn-1-yl)-6-chloro-3-((7-fluoroquinolin-2-yl)
methyl)pyrimidine-2,4(1H,3H)-dione (10n)
NMR (400 MHz, CDCl3)
d
8.59 (d, J ¼ 4.8 Hz, 2H), 7.09 (t, J ¼ 4.8 Hz,
The title compound was prepared from 2-(chloromethyl)-7-
fluoroquinoline in 42.7% yield according to the procedure for
1H), 5.32 (s, 2H), 5.25 (s, 1H), 4.51 (d, J ¼ 2.0 Hz, 2H), 3.60e3.33 (m,
1H), 3.25e3.22 (m, 1H), 3.01e2.97 (m, 1H), 2.73e2.71 (m, 1H),
2.55e2.45 (m,1H),1.97e1.93 (m,1H),1.86e1.82 (m,1H),1.76 (s, 3H),
1.68e1.60 (m, 1H), 1.30e1.25 (m, 1H); 13C NMR (125 MHz, CDCl3)
example 10a. 1H NMR (400 MHz, CDCl3)
d
8.08 (d, J ¼ 8.8 Hz, 1H),
7.77e7.73 (m, 1H), 7.63e7.60 (m, 1H), 7.30e7.25 (m, 2H), 6.05 (s,
1H), 5.41 (s, 2H), 4.82e4.81 (m, 2H), 1.83 (t, J ¼ 2.4 Hz, 3H). ESI-MS
calculated for (C18H14ClFN3O2) [M þ H]þ, 358.08, found 358.1.
d
165.36, 163.07, 159.52, 157.17, 152.26, 119.30, 89.04, 80.25, 73.64,
56.72, 51.65, 47.50, 46.10, 35.78, 31.07, 22.94, 3.63; ESI-MS calcu-
lated for (C18H23N6O2) [M þ H]þ, 355.19, found 355.2.
5.1.16. 1-(But-2-yn-1-yl)-6-chloro-3-((4-chloroquinolin-2-yl)
methyl)pyrimidine-2,4(1H,3H)-dione (10o)
5.1.21. (R)-3-((1H-Benzo[d]imidazol-2-yl)methyl)-6-(3-
aminopiperidin-1-yl)-1-(but-2-yn-1-yl)pyrimidine-2,4(1H,3H)-
dione (11e)
The title compound was prepared from 4-chloro-2-(chlor-
omethyl)quinoline in 58.0% yield according to the procedure for
example 10a. 1H NMR (400 MHz, CDCl3)
d
8.17 (d, J ¼ 8.0 Hz, 1H),
The title compound was prepared from 3-((1H-benzo[d]imidazol-
8.02 (d, J ¼ 8.4 Hz, 1H), 7.72e7.68 (m, 1H), 7.60e7.56 (m, 1H), 7.41 (s,
1H), 6.05 (s, 1H), 5.39 (s, 2H), 4.81e4.80 (m, 2H), 1.82 (t, J ¼ 2.4 Hz,
3H). ESI-MS calculated for (C18H14Cl2N3O2) [M þ H]þ, 374.05,
376.04, found 374.0, 376.0.
2-yl)methyl)-1-(but-2-yn-1-yl)-6-chloro
dione (10e) in 35.1% yield according to the procedure for example 11a.
1H NMR (400 MHz, CDCl3)
7.57e7.41 (m, 2H), 7.19e1.12 (m, 2H), 5.31
pyrimidine-2,4(1H,3H)-
d
(s, 2H), 5.18 (s,1H), 4.40 (s, 2H), 3.22e3.19 (m, 3H), 3.01e2.95 (m,1H),
2.66e2.59 (m,1H), 2.46e2.40 (m,1H),1.98e1.88 (m,1H), 1.75 (s, 3H),
1.64e1.55 (m, 1H), 1.32e1.26 (m, 1H); 13C NMR (125 MHz,
5.1.17. (R)-6-(3-Aminopiperidin-1-yl)-1-(but-2-yn-1-yl)-3-
methylpyrimidine-2,4(1H,3H)-dione (11a)
CDCl3 þ MeOH)
d 162.87,159.64,151.96,149.77,137.81,122.36,114.73,
88.57, 80.37, 73.26, 56.36, 51.30, 49.82, 47.13, 35.71, 30.82, 22.63, 3.25;
A mixture of 10a (200 mg, 0.94 mmol), (R)-3-aminopiperidine
dihydrochloride (244 mg, 1.41 mmol) and sodium bicarbonate
(395 mg, 4.7 mmol) was stirred with 100 mg of activated MS (4A) in
dry ethanol (10 mL) at 100 ꢀC for 2 h. The reaction was concentrated
in vacuo and purified by flash chromatography to yield 169 mg
ESI-MS calculated for (C21H25N6O2) [M þ H]þ, 393.20, found 393.20.
5.1.22. (R)-6-(3-Aminopiperidin-1-yl)-1-(but-2-yn-1-yl)-3-
(quinolin-2-ylmethyl)pyrimidine-2,4(1H,3H)-dione (11f)
The title compound was prepared from 1-(but-2-yn-1-yl)-6-
chloro-3-(quinolin-2-ylmethyl)pyrimidine-2,4 (1H,3H)-dione (10f)
in 89.7% yield according to the procedure for example 11a. 1H NMR
(65.2%) of the title compound. 1H NMR (400 MHz, MeOD)
d
5.32 (s,
1H), 4.67e4.57 (m, 2H), 3.38e3.36 (m, 2H), 3.32 (s, 3H), 3.05e2.98
(m, 1H), 2.84e2.79 (m, 1H), 2.61e2.56 (m, 1H), 2.08e2.04 (m, 1H),
1.96e1.91 (m,1H),1.87 (t, J ¼ 2.4 Hz, 3H),1.83e1.74 (m,1H),1.44e1.35
(400 MHz, CDCl3)
d
8.05 (d, J ¼ 8.8 Hz, 1H), 8.00 (d, J ¼ 8.8 Hz, 1H),
(m, 1H); 13C NMR (125 MHz, MeOD)
d
165.41, 161.55, 153.75, 89.32,
7.73 (d, J ¼ 8.0 Hz, 1H), 7.62 (t, J ¼ 7.2 Hz, 1H), 7.44 (t, J ¼ 7.2 Hz, 1H),
7.29 (t, J ¼ 8.4 Hz, 1H), 5.40 (s, 2H), 5.28 (s, 1H), 4.53 (d, J ¼ 2.4 Hz,
2H), 3.35e3.32 (m, 1H), 3.24e3.21 (m, 1H), 3.02e2.98 (m, 1H),
2.73e2.71 (m, 1H), 2.55e2.46 (m, 1H), 1.97e1.93 (m, 1H), 1.79e1.76
(m, 1H), 1.72 (s, 3H), 1.71e1.61 (m, 1H), 1.31e1.23 (m, 1H); 13C NMR
80.97, 74.80, 59.41, 52.82, 48.49, 36.62, 33.47, 28.12, 24.33, 3.07. ESI-
MS calculated for (C14H21N4O2) [M þ H]þ, 277.17, found 277.2.
5.1.18. (R)-6-(3-Aminopiperidin-1-yl)-1,3-di(but-2-yn-1-yl)
pyrimidine-2,4(1H,3H)-dione (11b)
(125 MHz, CDCl3)
d 163.04, 159.51, 156.49, 152.39, 147.65, 136.56,
The title compound was prepared from 1,3-di(but-2-yn-1-yl)-6-
chloropyrimidine-2,4(1H,3H)-dione (10b) in 68.2% yield according
129.26, 129.21, 127.37, 127.25, 126.02, 119.09, 89.05, 80.15, 73.68,
58.42, 51.48, 47.47, 46.47, 35.65, 32.44, 23.09, 3.59; ESI-MS calcu-
lated for (C23H26N5O2) [M þ H]þ, 404.21, found 404.2.
to the procedure for example 11a. 1H NMR (400 MHz, MeOD)
d 5.32
(s, 1H), 4.47e4.58 (m, 4H), 3.41e3.40 (m, 1H), 3.37e3.36 (m, 1H),
3.05e2.98 (m, 1H), 2.86e2.81 (m, 1H), 2.63e2.58 (m, 1H), 2.08e
2.04 (m, 1H), 1.97e1.93 (m, 1H), 1.87 (t, J ¼ 2.0 Hz, 3H), 1.81 (t,
J ¼ 2.0 Hz, 3H), 1.78e1.74 (m, 1H), 1.45e1.35 (m, 1H); 13C NMR
5.1.23. (R)-6-(3-Aminopiperidin-1-yl)-3-(benzo[f]quinolin-3-
ylmethyl)-1-(but-2-yn-1-yl)pyrimidine-2,4(1H,3H)-dione (11g)
The title compound was prepared from 3-(benzo[f]quinolin-3-
ylmethyl)-1-(but-2-yn-1-yl)-6-chloropyrimidine-2,4(1H,3H)-
dione (10g) in 85.8% yield according to the procedure for example
(125 MHz, MeOD) d 164.15, 161.83, 152.98, 89.32, 81.17, 78.93, 74.73,
74.55, 59.37, 52.79, 48.47, 36.77, 33.45, 31.57, 24.31, 3.11, 3.05. ESI-
MS calculated for (C17H23N4O2) [M þ H]þ, 315.18, found 315.2.
11a. 1H NMR (400 MHz, CDCl3)
d
8.77 (d, J ¼ 8.8 Hz, 1H), 8.46 (d,
J ¼ 8.0 Hz, 1H), 7.88e7.80 (m, 3H), 7.58e7.50 (m, 2H), 7.41 (d,
J ¼ 8.4 Hz, 1H), 5.44 (s, 2H), 5.24 (s, 1H), 4.48 (d, J ¼ 2.0 Hz, 2H),
3.26e3.23 (m, 1H), 3.17e3.14 (m, 1H), 2.92e2.87 (m, 1H), 2.64e2.59
(m, 1H), 2.43e2.39 (m, 1H), 1.88e1.84 (m, 1H), 1.77e1.76 (m, 1H),
1.73 (s, 3H), 1.62e1.53 (m, 1H), 1.22e1.16 (m, 1H); 13C NMR
5.1.19. (R)-6-(3-Aminopiperidin-1-yl)-3-benzyl-1-(but-2-yn-1-yl)
pyrimidine-2,4(1H,3H)-dione (11c)
The title compound was prepared from 3-benzyl-1-(but-2-yn-
1-yl)-6-chloropyrimidine-2,4(1H,3H)-dione (10c) in 67.0% yield

318
H. Xie et al. / European Journal of Medicinal Chemistry 68 (2013) 312e320
(125 MHz, CDCl3)
d
163.08, 159.48, 156.06, 152.35, 147.63, 131.46,
121.87, 88.83, 80.14, 73.48, 57.97, 51.29, 47.29, 43.98, 35.52, 32.08,
25.04, 22.91, 3.47; ESI-MS calculated for (C24H28N5O2) [M þ H]þ,
418.22, found 418.2.
131.25, 130.58, 129.51, 128.53, 128.19, 126.90, 124.15, 122.47, 119.13,
89.05, 80.19, 73.66, 57.83, 51.51, 47.46, 46.29, 35.70, 31.98, 23.02,
3.61; ESI-MS calculated for (C27H28N5O2) [M þ H]þ, 454.22, found
454.2.
5.1.28. (R)-6-(3-Aminopiperidin-1-yl)-1-(but-2-yn-1-yl)-3-((6-
methoxyquinolin-2-yl)methyl)pyrimidine-2,4(1H,3H)-dione (11l)
The title compound was prepared from 1-(but-2-yn-1-yl)-6-
chloro-3-((6-methoxyquinolin-2-yl)methyl) pyrimidine-2,4(1H,3H)-
dione (10l) in 88.4% yield according to the procedure for example 11a.
5.1.24. (R)-6-(3-Aminopiperidin-1-yl)-3-((6-bromoquinolin-2-yl)
methyl)-1-(but-2-yn-1-yl)pyrimidine-2,4(1H,3H)-dione (11h)
The title compound was prepared from 3-((6-bromoquinolin-2-
yl)methyl)-1-(but-2-yn-1-yl)-6-chloro
dione (10h) in 86.3% yield according to the procedure for example
11a. 1H NMR (400 MHz, CDCl3)
pyrimidine-2,4(1H,3H)-
1H NMR (400 MHz, CDCl3)
d
7.94 (d, J ¼ 8.4 Hz,1H), 7.89 (d, J ¼ 9.2 Hz,
1H), 7.28e7.24 (m, 2H), 7.00 (d, J ¼ 2.4 Hz,1H), 5.37 (s, 2H), 5.28(s,1H),
4.53 (d, J ¼ 1.6 Hz, 2H), 3.86 (s, 3H), 3.34e3.32 (m,1H), 3.24e3.21 (m,
1H), 3.03e2.99 (m, 1H), 2.73e2.68 (m, 1H), 2.53e2.50 (m, 1H), 1.98e
1.94 (m, 1H), 1.86e1.83 (m, 1H), 1.78 (s, 3H), 1.69e1.65 (m, 1H), 1.29e
d
7.95 (d, J ¼ 8.8 Hz, 1H), 7.88e7.84
(m, 2H), 7.68e7.65 (m, 1H), 7.31 (d, J ¼ 8.4 Hz, 1H), 5.37 (s, 2H), 5.28
(s, 1H), 4.54 (d, J ¼ 2.4 Hz, 2H), 3.36e3.34 (m, 1H), 3.25e3.22 (m,
1H), 3.04e2.98 (m, 1H), 2.75e2.70 (m, 1H), 2.54e2.51 (m, 1H),
1.98e1.94 (m, 1H), 1.88e1.83 (m, 1H), 1.77 (t, J ¼ 2.4 Hz, 3H), 1.74e
1.27 (m, 1H); 13C NMR (125 MHz, CDCl3)
d 163.06, 159.39, 157.35,
153.88, 152.29, 143.63, 135.34, 130.48, 128.13, 121.84, 119.42, 104.93,
88.97, 80.11, 73.63, 57.47, 55.36, 51.46, 47.39, 46.27, 35.65, 31.68, 22.94,
3.55; ESI-MS calculated for (C24H28N5O3) [M þ H]þ, 434.22, found
434.2.
1.64 (m,1H), 1.33e1.27 (m, 1H); 13C NMR (125 MHz, CDCl3)
d 162.99,
159.51, 156.92, 152.23, 146.03, 135.50, 132.58, 130.79, 129.31, 128.22,
119.99, 119.70, 88.83, 80.14, 73.55, 57.58, 51.43, 47.36, 46.25, 35.68,
31.77, 22.91, 3.52; ESI-MS calculated for (C23H25BrN5O2) [M þ H]þ,
482.12, 484.12, found 482.1, 484.1.
5.1.29. (R)-6-(3-Aminopiperidin-1-yl)-1-(but-2-yn-1-yl)-3-((7-
chloroquinolin-2-yl)methyl)pyrimidine-2,4(1H,3H)-dione (11m)
The title compound was prepared from 1-(but-2-yn-1-yl)-6-
chloro-3-((7-chloroquinolin-2-yl)methyl) pyrimidine-2,4(1H,3H)-
dione (10m) in 66.4% yield according to the procedure for example
5.1.25. (R)-6-(3-Aminopiperidin-1-yl)-1-(but-2-yn-1-yl)-3-((6-
chloroquinolin-2-yl)methyl)pyrimidine-2,4(1H,3H)-dione (11i)
The title compound was prepared from 1-(but-2-yn-1-yl)-6-
chloro-3-((6-chloroquinolin-2-yl)methyl) pyrimidine-2,4(1H,3H)-
dione (10i) in 82.9% yield according to the procedure for example
11a. 1H NMR (400 MHz, CDCl3)
d
8.03 (d, J ¼ 8.4 Hz, 1H), 7.99 (s, 1H),
7.67 (d, J ¼ 8.4 Hz, 1H), 7.41e7.39 (m, 1H), 7.30 (d, J ¼ 8.4 Hz, 1H),
5.39 (s, 2H), 5.30 (s, 1H), 4.56 (d, J ¼ 2.0 Hz, 2H), 3.38e3.36 (m, 1H),
3.27e3.24 (m,1H), 3.06e3.02 (m,1H), 2.77e2.72 (m,1H), 2.56e2.54
(m, 1H), 1.99e1.96 (m, 1H), 1.90e1.86 (m, 1H), 1.79 (s, 3H), 1.75e1.70
11a. 1H NMR (400 MHz, CDCl3)
d
7.95 (d, J ¼ 8.8 Hz, 1H), 7.91 (d,
J ¼ 8.8 Hz, 1H), 7.70 (d, J ¼ 2.4 Hz, 1H), 7.55e7.52 (m, 1H), 7.30 (d,
J ¼ 8.4 Hz, 1H), 5.37 (s, 2H), 5.28 (s, 1H), 4.53 (d, J ¼ 2.4 Hz, 2H),
3.35e3.32 (m,1H), 3.24e3.21 (m,1H), 3.03e2.97 (m,1H), 2.74e2.69
(m, 1H), 2.53e2.50 (m, 1H), 1.97e1.93 (m, 1H), 1.87e1.82 (m, 1H),
1.76 (t, J ¼ 2.4 Hz, 3H), 1.71e1.64 (m, 1H), 1.31e1.26 (m, 1H); 13C
(m, 1H), 1.34e1.29 (m, 1H); 13C NMR (125 MHz, CDCl3)
d 162.97,
159.53, 157.48, 152.35, 147.94, 136.27, 134.96, 128.57, 128.25, 126.97,
125.56, 119.40, 88.96, 80.13, 73.62, 58.45, 51.47, 47.44, 46.16, 35.61,
32.47, 23.07, 3.55; ESI-MS calculated for (C23H25ClN5O2) [M þ H]þ,
438.17, found 438.2.
NMR (125 MHz, CDCl3)
d 162.98, 159.44, 156.71, 152.15, 145.76,
135.57, 131.50, 130.59, 130.00, 127.64, 125.91, 119.96, 88.76, 80.11,
73.49, 57.06, 51.40, 47.29, 46.17, 35.67, 31.34, 22.82, 3.47; ESI-MS
calculated for (C23H25ClN5O2) [M þ H]þ, 438.17, found 438.2.
5.1.30. (R)-6-(3-Aminopiperidin-1-yl)-1-(but-2-yn-1-yl)-3-((7-
fluoroquinolin-2-yl)methyl)pyrimidine-2,4(1H,3H)-dione (11n)
The title compound was prepared from 1-(but-2-yn-1-yl)-6-
chloro-3-((7-fluoroquinolin-2-yl)methyl) pyrimidine-2,4(1H,3H)-
dione (10n) in 92.5% yield according to the procedure for example
5.1.26. (R)-6-(3-Aminopiperidin-1-yl)-1-(but-2-yn-1-yl)-3-((6-
fluoroquinolin-2-yl)methyl)pyrimidine-2,4(1H,3H)-dione (11j)
The title compound was prepared from 1-(but-2-yn-1-yl)-6-
chloro-3-((6-fluoroquinolin-2-yl)methyl) pyrimidine-2,4(1H,3H)-
dione (10j) in 88.1% yield according to the procedure for example
11a. 1H NMR (400 MHz, CDCl3)
d
8.05 (d, J ¼ 8.8 Hz, 1H), 7.75e7.71
(m, 1H), 7.64e7.61 (m, 1H), 7.28e7.22 (m, 2H), 5.40 (s, 2H), 5.31 (s,
1H), 4.56 (d, J ¼ 1.6 Hz, 2H), 3.38e3.36 (m, 1H), 3.27e3.24 (m, 1H),
3.06e3.02 (m, 1H), 2.77e2.72 (m, 1H), 2.56e2.54 (m, 1H), 2.00e
1.97 (m, 1H), 1.90e1.86 (m, 1H), 1.80 (s, 3H), 1.75e1.72 (m, 1H),
11a. 1H NMR (400 MHz, CDCl3)
d 7.99e7.96 (m, 2H), 7.40e7.29 (m,
3H), 5.37 (s, 2H), 5.28 (s, 1H), 4.53 (d, J ¼ 2.4 Hz, 2H), 3.35e3.32 (m,
1H), 3.24e3.21 (m, 1H), 3.03e2.98 (m, 1H), 2.73e2.68 (m, 1H),
2.52e2.50 (m, 1H), 1.97e1.93 (m, 1H), 1.87e1.82 (m, 1H), 1.77 (t,
J ¼ 2.0 Hz, 3H), 1.71e1.61 (m, 1H), 1.31e1.26 (m, 1H); 13C NMR
1.34e1.29 (m, 1H); 13C NMR (125 MHz, CDCl3)
d 162.96, 162.85,
159.50, 157.52, 152.30, 148.52, 136.36, 129.31, 124.16, 118.40, 116.35,
112.80, 88.91, 80.10, 73.59, 58.11, 51.44, 47.40, 46.22, 35.61, 32.19,
23.00, 3.51; ESI-MS calculated for (C23H25FN5O2) [M þ H]þ, 422.20,
found 422.2.
(125 MHz, CDCl3 þ MeOH)
d 163.12, 159.99, 159.52, 155.65, 152.15,
144.30, 136.11, 131.02, 127.67, 119.74, 119.43, 110.30, 88.76, 80.22,
73.26, 57.17, 51.42, 47.18, 46.04, 35.57, 31.41, 22.76, 3.27; ESI-MS
calculated for (C23H25FN5O2) [M þ H]þ, 422.20, found 422.2.
5.1.31. (R)-6-(3-Aminopiperidin-1-yl)-1-(but-2-yn-1-yl)-3-((4-
chloroquinolin-2-yl)methyl)pyrimidine-2,4(1H,3H)-dione (11o)
The title compound was prepared from 1-(but-2-yn-1-yl)-6-
chloro-3-((4-chloroquinolin-2-yl)methyl) pyrimidine-2,4(1H,3H)-
dione (10o) in 71.9% yield according to the procedure for example
5.1.27. (R)-6-(3-Aminopiperidin-1-yl)-1-(but-2-yn-1-yl)-3-((6-
methylquinolin-2-yl)methyl)pyrimidine-2,4(1H,3H)-dione (11k)
The title compound was prepared from 1-(but-2-yn-1-yl)-6-
chloro-3-((6-methylquinolin-2-yl)methyl) pyrimidine-2,4(1H,3H)-
dione (10k) in 82.1% yield according to the procedure for example
11a. 1H NMR (400 MHz, CDCl3)
d
8.13 (d, J ¼ 8.4 Hz, 1H), 8.02 (d,
11a. 1H NMR (400 MHz, CDCl3)
d
7.98 (d, J ¼ 8.4 Hz, 1H), 7.92e7.87
J ¼ 8.4 Hz, 1H), 7.68 (t, J ¼ 7.6 Hz, 1H), 7.55 (t, J ¼ 7.6 Hz, 1H), 7.38 (s,
1H), 5.37 (s, 2H), 5.30 (s, 1H), 4.55 (s, 2H), 3.38e3.35 (m, 1H), 3.26e
3.24 (m, 1H), 3.08e2.97 (m, 1H), 2.82e2.67 (m, 1H), 2.60e2.47 (m,
1H),1.98e1.96 (m, 1H), 1.88e1.87 (m, 1H), 1.79 (s, 3H), 1.75e1.65 (m,
(m, 2H), 7.82e7.79 (m, 1H), 7.21 (d, J ¼ 8.4 Hz, 1H), 5.23e5.22 (m,
3H), 4.49 (d, J ¼ 1.2 Hz, 2H), 3.31e3.28 (m, 1H), 3.20e3.17 (m, 1H),
3.01e2.94 (m, 1H), 2.68 (s, 3H), 2.48e2.46 (m, 1H), 1.96e1.92 (m,
1H), 1.85e1.80 (m, 1H), 1.78 (t, J ¼ 2.4 Hz, 3H), 1.71e1.59 (m, 2H),
1H), 1.34e1.26 (m, 1H); 13C NMR (125 MHz, CDCl3)
d 162.87, 159.59,
1.29e1.27 (m, 1H); 13C NMR (125 MHz, CDCl3)
d
162.86, 159.23,
156.62, 152.35, 148.49, 142.98, 130.19, 129.63, 127.05, 125.47, 123.80,
119.16, 89.01, 80.28, 73.58, 58.68, 51.49, 47.49, 46.22, 35.72, 32.66,
158.70, 152.02, 146.98, 136.11, 134.27, 130.53, 128.27, 127.65, 125.98,

H. Xie et al. / European Journal of Medicinal Chemistry 68 (2013) 312e320
319
23.12, 14.06, 3.60; ESI-MS calculated for (C23H25ClN5O2) [M þ H]þ,
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Acknowledgments
We thank Tingting Xu for the structural superposition and the
corresponding discussion. This research was supported by Grant
from the Bureau of Science and Technology of Guangzhou Munic-
ipality (No. 2009Z1-E871) and the Natural Science Foundation of
China (NSFC 21102145).
Appendix A. Supplementary data
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.ejmech.2013.08.010.

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