Discovery of novel potent GPR40 agonists containing imidazo[1,2-a]pyridine core as antidiabetic agents

Article abstract of DOI:10.1016/j.bmc.2020.115574

Free fatty acid receptor 1 (FFA1 or GPR40) has been studied for many years as a target for the treatment of type 2 diabetes mellitus. In order to increase potency and reduce hepatotoxicity, a series of novel compounds containing imidazo[1,2-a]pyridine sca

Full text of DOI:10.1016/j.bmc.2020.115574

Journal Pre-proofs
Discovery of novel potent GPR40 agonists containing imidazo[1,2-a]pyridine
core as antidiabetic agents
Zhiwen Ye, Chunxia Liu, Feng Zou, Yan Cai, Bin Chen, Yuxing Zou, Jiaxian
Mo, Ting Han, Wenlong Huang, Qianqian Qiu, Hai Qian
PII:
DOI:
Reference:
S0968-0896(20)30404-1
https://doi.org/10.1016/j.bmc.2020.115574
BMC 115574
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Bioorganic & Medicinal Chemistry
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Revised Date:
Accepted Date:
26 February 2020
25 May 2020
26 May 2020
Please cite this article as: Ye, Z., Liu, C., Zou, F., Cai, Y., Chen, B., Zou, Y., Mo, J., Han, T., Huang, W., Qiu,
Q., Qian, H., Discovery of novel potent GPR40 agonists containing imidazo[1,2-a]pyridine core as antidiabetic
agents, Bioorganic & Medicinal Chemistry (2020), doi: https://doi.org/10.1016/j.bmc.2020.115574
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Discovery of novel potent GPR40 agonists containing
imidazo[1,2-a]pyridine core as antidiabetic agents
Zhiwen Ye a, Chunxia Liu a, Feng Zou a, Yan Cai a, Bin Chen a, Yuxing Zou a, Jiaxian Mo a,
Ting Hana, Wenlong Huang a, b, Qianqian Qiua,* Hai Qian a, b,*
aCenter of Drug Discovery, State Key Laboratory of Natural Medicines, China
Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, PR China
bJiangsu Key Laboratory of Drug Discovery for Metabolic Disease, China Pharmaceutical
University, 24 Tongjiaxiang, Nanjing, 210009, PR China
* Corresponding author.
Qianqian Qiu, Center of Drug Discovery, China Pharmaceutical University, 24 Tongjiaxiang,
Nanjing, 210009, PR China, Email: qianqianqiu_cpu@126.com
Hai Qian, Center of Drug Discovery, State Key Laboratory of Natural Medicines, China
Pharmaceutical
University,
24
Tongjiaxiang,
Nanjing,
210009,
PR
China,E-mail:qianhai24@163.com (H. Qian)

Abstract
Free fatty acid receptor 1 (FFA1 or GPR40) has been studied for many years as a
target for the treatment of type 2 diabetes mellitus. In order to increase potency and
reduce hepatotoxicity, a series of novel compounds containing imidazo[1,2-a]pyridine
scaffold as GPR40 agonist were synthesized. Compound I-14 was identified as an
effective agonist as shown by the conspicuous drop in blood glucose in normal and
diabetic mice. It had no risk of hepatotoxicity compared with TAK-875. Moreover,
good pharmacokinetic (PK) properties of I-14 were observed (CL=27.26mL/h/kg,
t1/2=5.93h). The results indicate that I-14 could serve as a possible candidate to treat
diabetes.
Keywords: type 2 diabetes mellitus, GPR40 agonists, phenylpropanoic acid,
hepatotoxicity
1. Introduction
As a metabolic disease, type 2 diabetes mellitus (T2DM) seriously affects the
quality of patients' life, and it has caused a series of health problems. People with
diabetes mellitus usually have glucose intolerance as well as insulin insufficient and
resistance.1, 2 In the clinic, abundant oral antidiabetic agents including sulfonylurea,
alpha-glucosidase inhibitors, DPP-4(Dipeptidyl peptidase-4) inhibitors and others
4
have been on the market.3, Nevertheless, side effects, such as high risk of
hypoglycemia, poor pharmacokinetics and drug resistance cannot be ignored. Thus,
the impact of these agents on clinical treatment has been limited.5, 6 Therefore, novel
effective antidiabetic drugs without critical side effects are urgently needed.
Free fatty acid receptor 1 (FFA1 or GPR40), a G protein coupled receptor, is
highly expressed in pancreatic β-cells.7 In the last decade, it has been considered as a

potential anti-diabetic target.8 The target is composed of seven alpha-helices segments
connected by three intracellular and three extracellular loops, embedding in plasma
membrane. The extracellular N (amino)-terminal domain, along with the loops,
contributes to the formation of a pocket, which is responsible for ligand binding.9, 10
After binding, pathways to protein kinase C were activated. This ultimately leads to
the release of Ca2+ store from the cytoplasm through the plasma membrane to the
extracellular and then activates protein kinase C to enhance insulin secretion11. This
target has been extensively studied so far due to the glucose dependence of this target
during the hyperglycemic process.11
As reported in a recent review,12 among all agonists, phenylpropanoic acid is the
most classic scaffold. Representative compounds, such as TAK-875 and
AMG-837(Figure 1), have been estimated in clinical trials.12 However, the
hepatotoxicity found in clinical trials leads to the abrogation of studies on these
compounds. For instance, TAK-875 was terminated in Phase III trials, even if it has
good pharmacokinetic (PK) profiles and potency.13 The mechanism of hepatotoxicity
is still under research. It is generally accepted that hepatotoxicity is not related to
target for its low expression in liver.14, 15 Zheng et al24 in 2017 reported some novel
phenylsulfonyl acetic acid derivatives for type 2 diabetes mellitus. The derivatives
obtained by introducing a sulfonyl group in the β-position of the phenylpropionic acid
structure can both improve the efficacy and avoid liver toxicity.
Figure 1. Representatives of synthetic GPR40 agonists.16-21

The compounds in this study were divided into two moieties (Figure 2). One
moiety was phenylpropanoic acid that acted as an anchor connected to the highly
polar region of the binding site. To avoid oxidation on the β position, the propargyl
group at β position was inserted instead of tetrahydrofuran ring. Moreover, it has been
reported that the effect of introducing propargyl group may be the best method to
prevent β-oxidation.16 Another fragment was 2-phenylimidazo[1,2-a]pyridine as a
hydrophobic part. Unlike the improved method of Zheng et al., We adopted a method
of increasing the polarity of the biphenyl structure to avoid hepatotoxicity. The flat
surface feature of biphenyl group was expected to be retained in TAK-875 while
increasing the polarity. The introduced nitrogen atoms improved hydrophilicity and
decreased the potential risk of hepatotoxicity of TAK-875. After the determination of
the basic framework, electron withdrawing group and electron donating group were
introduced into the retaining benzene ring. Simulation from the molecular docking
software shows that the designed molecule could dock with the target well. Biological
activities show that the compounds, such as compound I-14, containing strong
electron-donating group have the best potency.
Figure 2. Design of novel GPR40 agonists with heterocyclic ring scaffold.
2. Results and discussion

2.1 Synthesis
The synthetic routes of compounds are shown in Scheme 1. Compound A and
2,2-Dimethyl-1,3-dioxane-4,6-dione were heated in water to obtain compound B.
Compound was prepared via reaction between compound and
C
B
1-propynylmagnesium bromide. Compound C was then heated and hydrolyzed to get
compound D. The compound E was made after esterification of compound D.
Starting from acetophenone substituted by various groups, compound G was
obtained through free radical reaction between compound F and copper bromide.
Employing sodium carbonate as the base, compound G reacted with 6-aminonicotinic
acid ester and 2-aminonicotinic acid ester to give compounds H1 and H2,
respectively. Compound H1 reacted with LiAlH4 to afford compound I1. Compound
I1 reacted with SOCl2 to form compound J1. Treatment of Compound E with
compound J1 in the presence of potassium carbonate afforded compound K1.
Compound І was obtained after hydrolysis and acidification of compound K1.
Compound Ⅱ was successfully synthesized from compound H2 followed by a similar
synthetic method to the synthesis of compound І as mentioned above.The structures
of target compounds were listed in Table 1.

Scheme 1. Synthesis of target compounds І-1~14, Ⅱ-1~14. Reagents and conditions:
(a) 2,2-Dimethyl-1,3-dioxane-4,6-dione, H2O, 75℃, 2h; (b) 1-Propynylmagnesium
bromide, THF, N2, rt, overnight; (c) H2O, DMF, 100℃, overnight; (d) MeOH, H2SO4,
65℃, 10h; (e) CuBr2, EA, N2, 70℃, 12h; (f) Methyl 6-aminonicotinate, EtOH,
Na2CO3, 75℃, 6h; (g) LiAlH4, THF, 0℃, 10h; (h) SOCl2, DCM, rt, overnight; (i)
Methyl 2-Aminoisonicotinate, EtOH, Na2CO3, 75℃, 6h; (j) acetonitrile, Cs2CO3, KI,
Benzyltriethylammonium chloride, 65℃, overnight; (k) THF/CH3OH/H2O, LiOH, rt,
4h; HCl(two steps).
2.2 Agonistic activities of target compounds and Structure activity
relationships(SAR) study
In view of the fact that the hepatotoxicity of TAK-875 may be caused by the
biphenyl moiety in its structure,22 one benzene ring in biphenyl was replaced with a
polar heterocyclic structure in order to increase its polarity and reduce the potential
hepatotoxicity. The imidazopyridine structure was selected in order to obtain a

compound which is active and has no toxic side effects. It was found using docking
software analysis that the linker connected with the imidazopyridine had better
performance at the 6, 7 sites than at the 5 and 8 sites. The effect of substituent on the
benzene ring on potency was then investigated. To this end, the electron-donating
groups, electron-withdrawing groups, strong electron-donating groups and strong
electron-withdrawing groups were introduced. The in vitro and in vivo results indicate
that the compounds with substituents were more effective than the compound without
substituents. Moreover, compounds that were introduced with strong electron
donating groups had the highest efficacy.
Table 1.The structures and agonistic activities of target compounds
R1
N
O
R2
R1
N
N
N
O
COOH
COOH
R3
R2
II
R3
I
Cpd.
R
EC50 (nM)a
TAK-875
І -1
53±5.9
R1=H, R2=H, R3=H
979±17.8
496±11.4
623±15.9
528±16.6
1046±18.1
389±7.5
507±8.3
І -2
R1=H, R2=CH2CH3, R3=H
R1=H, R2=F, R3=H
І -3
І -4
R1=H, R2=CH(CH3)2, R3=H
R1=H, R2=H, R3=CH3
R1=CH3, R2=H, R3=H
R1=H, R2=CH3, R3=H
І -5
І -6
І -7

І -8
R1=H, R2=CF3, R3=H
R1=CH3, R2=CH3, R3=H
R1=F, R2=H, R3=H
558±13.9
316±7.4
І -9
І -10
І -11
І -12
І -13
І -14
Ⅱ-1
583±12.1
417±7.2
R1=H, R2=C6H11, R3=H
R1=F, R2=F, R3=H
825±23.5
157±8.3
R1=OCH2CH3, R2=H, R3=H
R1=H, R2=OCH3, R3=H
R1=H, R2=H, R3=H
47±9.8
1258±22.9
503±7.8
Ⅱ-2
R1=CH3, R2=CH3, R3=H
R1=H, R2=CH2CH3, R3=H
R1=F, R2=H, R3=H
Ⅱ-3
671±14.1
705±17.3
615±19.8
559±12.6
792±14.6
618±17.5
459±16.8
1508±15.7
674±12.7
783±21.2
639±19.6
231±9.3
Ⅱ-4
Ⅱ-5
R1=H, R2=CH(CH3)2, R3=H
R1=H, R2=C6H11, R3=H
R1=F, R2=F, R3=H
Ⅱ-6
Ⅱ-7
Ⅱ-8
R1=H, R2=CH3, R3=H
R1=CH3, R2=H, R3=H
R1=H, R2=H, R3=CH3
R1=H, R2=CF3, R3=H
R1=H, R2=F, R3=H
Ⅱ-9
Ⅱ-10
Ⅱ-11
Ⅱ-12
Ⅱ-13
Ⅱ-14
R1=F, R2=H, R3=F
R1=OCH2CH3, R2=H, R3=H
aEC50 values are averages of three independent determinations.

2.3 OGTT in normoglycemic ICR mice
Compounds (І-13, І-14, and Ⅱ-14) were selected to estimate the
glucose-lowering effects in mice for their high potency (Figure 3). As shown in
Figure 3, the abilities of compounds І-13, І-14 and Ⅱ-14 on decreasing the levels of
blood glucose were similar to that of TAK-875 at the same dose. AUC0-120min of
plasma glucose was significantly lower than the vehicle group. In addition, one hour
after administration, the blood glucose tended to return to the initial blood glucose,
and there was no continuous violently decline, indicating its low risk of
hypoglycemia.
Figure 3. Effects of compounds (І-13, І-14 and Ⅱ-14) (30mg/kg) during OGTTs in
ICR mice. (A) and (C) represented changes of blood glucose levels with time after
administration orally, respectively. (B) and (D) represented the corresponding area

under the curve (AUC0-120min )of blood glucose. Values are expressed by mean ± SD
(n = 6 per group). Compared to normal control, a one-way ANOVA with Tukey's
multiple-comparison post hoc test was used to analyze *p<0.05, **p<0.01 and ***p
<0.001.
2.4 Glucose-lowering effect in STZ mice
The male HF/STZ mice, which was a high fat fed and streptozotocin-treated
diabetic model, has decreased β cell capacity and insulin resistance. These mice were
administered by oral to further estimate the glucose-lowering effects of compound
І-13, І-14, Ⅱ-14. As shown in Figure 4, the plasma glucose was effectively
controlled in the three compound-treated groups, and the AUC0-120min was close to that
of TAK-875. Significantly, compound І-14-treated group improved the glucose
tolerance. These results suggested that compound І-14 had sufficient effectiveness for
the control of hyperglycemia state in type 2 diabetic mice. As a result, І-14 was
selected for further in-depth studies.

Figure 4. OGTTs in diabetic HF/STZ mice (30mg/kg). (A) and (C) Effects of
compounds І-13, І-14, Ⅱ-14 on blood glucose levels; (B) and (D) corresponding area
under the curve (AUC0-120min) of glucose. Values are expressed by mean ± SD (n = 6
per group). Compared to negative control, a one-way ANOVA with Tukey's
multiple-comparison post hoc test was used to analyze *p<0.05, **p<0.01 and ***p
<0.001.
2.5 Molecular modeling study
As shown in Figure 5, compound I-14 and TAK-875 bound to the same site of target
with largely deviation of biphenyl scaffold. The hydrogen bond forces between the
carboxyl and the amino acid residues (R2258, R183, Y91, Y2240) allowed the
compound to anchor at this site. However, the Pi-Pi stacking force between the
original biphenyl moiety and PHE 142 disappeared due to the introduction of nitrogen
atoms, which was different from the situation in TAK-875. Moreover, it can be seen

from Figure 5C that after the main force was generated by the carboxyl group and the
binding site, the spatial position of the outer hydrophobic region part was greatly
different. These may explain why the compound had the similar or even better
performance compared with TAK-875.
Figure 5. Docking diagrams of compound I-14 and TAK-875 with target GPR40
(PDB code: 4PHU), respectively. Important residues are marked in black. The yellow
dashed lines represent hydrogen bonds. (A) 3D docking diagram of compound I-14
and GPR40. (B) 3D docking diagram of TAK-875 and GPR40. (C) Overlay of
TAK-875 (green) and compound I-14 (blue) bound to GPR40. (D) 2D docking
diagram of compound I-14 and GPR40. (E) 2D docking diagram of TAK-875 and
GPR40.
2.6 Dose-dependent experiment in normoglycemic ICR mice
The hypoglycemic effects of compound I-14 at different doses were assessed. As
shown in Figure 6, blood glucose was significantly suppressed after compound I-14
at different doses was administrated orally. The hypoglycemic effect of compound
I-14 gradually increased with the increase of dose. Moreover, when the dose reached
90 mg / kg, which was 3 times the dose of positive control (TAK-875), there was still
no hypoglycemia, which suggests that compound I-14 might have no risk of
hypoglycemia.

Figure 6. Effects of compound І-14 at different dose during OGTT in ICR mice. (A)
represented changes of blood glucose levels with time after administration orally. (B)
represented the corresponding area under the curve (AUC0-120min) of blood glucose.
Values are expressed by mean ± SD (n =5 per group). Compared to normal control, a
one-way ANOVA with Tukey's multiple-comparison post hoc test was used to
analyze *p<0.05, **p<0.01 and ***p <0.001.
2.7 The risk of hepatotoxicity
To further assess the safety of compound І-14, a four-week long-term oral
administration experiment was conducted. As shown in Figure 7, after end of the
trial, blood parameters (ALT, AST) of І-14-treated group did not change significantly
compared to the negative control group. However, blood parameters (ALT, AST) of
TAK-875-treated group were higher than that of the normal group and the negative
control group. These data indicate that the risk of hepatotoxicity of compound І-14
was much lower than that of TAK-875.

Figure 7. Blood parameters (ALT,AST) of four groups. (A) ALT of four groups. (B)
AST of four groups. Values are expressed by mean ± SD (n =6 per group). Compared
to Normal group, a one-way ANOVA with Tukey's multiple-comparison post hoc test
was used to analyze *p<0.05, **p<0.01 and ***p <0.001.
2.8 Pharmacokinetic evaluation
Compound І-14 displayed good pharmacokinetic properties, especially in terms
of lower clearance (CL)(27.26mL/h/kg) compared to TAK-875(34.16mL/h/kg).23 The
peak time(Tmax) (8.26h) of the blood concentration of the compound was much longer
than that of TAK-875(1.0h).23 In addition, the plasma half-life time(t1/2) was extent,
which was longer than that for the TAK-875(4.7h).23 All these results suggest that the
designed strategy on improving pharmacokinetic distribution are efficacious.
Table 3. PK parameters of compound І-14
CL(mL/h/kg) Cmax(ug/mL)
27.26 16.34
Tmax(h)
8.26
AUC0-24h(ug·h/mL)
288.42
t1/2(h)
5.93
I-14
A dose of 10mg/kg was administered. Date is represented as mean values (rats, n=4). CL
represents clearance, Cmax represents peak concentration, Tmax represents peak time, AUC0-24h
represents area under the curve, t1/2 represents half-life time.

3. Conclusion
In summary, an excellent agonist, compound І-14, was identified by SAR studies
and hypoglycemic assays and toxicity screening starting with the existing GPR40
agonists. No hepatotoxicity for compound І-14 was observed over long-term
administration compared to TAK-875. Significant in vivo hypoglycemic effects were
observed. Furthermore, compound І-14-treated group had a good PK distribution,
especially in lower clearance. The potential of the phenylpropionic acid structure in
lowering blood glucose was presented, and the imidazopyridine structure could avoid
hepatotoxicity and improved the pharmacokinetic in vivo, providing a new and safe
agonist to treat T2DM.
4. Experimental section
4.1. Methods and Materials
All reactions were performed in clean and dry glass bottles under magnetic
agitation. Except for individual reagents, all reagents were weighed at room
temperature and treated in air. All raw materials and solvents are commercially
available. Most of the intermediates and products, in the synthesis process were
purified by silica gel column chromatography and monitored by TLC using UV light.
Structures of compounds were identified by NMR (Bruker ACF-300Q NMR
spectrometer). Chemical shifts were expressed as parts per million (ppm), and
coupling constants (J value) are reported in Hertz (Hz). We also used LC-MS to
conform the molecular weight and purity. Using Waters LC-MS system, the LC-MS
spectra were provided. The purity of all target compounds >95%. TAK-875 was
synthesized according to reported process.23
(B)5-[(4-Hydroxyphenyl) methylene]-2, 2-dimethyl-1, 3-dioxane-4, 6-Dione

The 4-formylphenol (6g, 49.44mmol) ， commercially available compound ， was
dissolved in water followed by the addition of 2, 2-Dimethyl-1, 3-dioxane-4, 6-dione
(8g, 49,92mmol), and the reaction was stirred at 75 °C for 2 hours. After the reaction
was complete, the product was filtered. The filter cake was washed with water, beaten
with ethanol, filtered again, and dried in a ventilated place. Yellow powdery product
B (6.86g, 55.9%) was obtained without further purification.
(C)5-[1-(4-Hydroxyphenyl)-2-butynyl]-2,2-dimethyl-1,3-dioxane-4,6-dione
Compound B (0.8g, 3.23mmol) was dissolved in dry tetrahydrofuran, and
1-propyne-magnesium bromide was slowly added dropwise under nitrogen protection.
Suspension was formed from the yellow clear solution. The mixture was stirred at
room temperature for 8h. The system was then quenched by saturated ammonium
chloride solution followed by the addition of 1N hydrochloric acid to adjust the pH to
1-2. Ethyl acetate was added. The organic layer was washed after combining the
extracts and dried over anhydrous Na2SO4. Ethyl acetate was evaporated under
reduced pressure. Compound C as an orange solid was obtained via purification using
silica gel column chromatography (0.9g, 96.7%).
(D)4-Hydroxy-β-1-propyn-1-ylbenzenepropanoic acid
To a solution of C (1.1 g, 3.82mmol) in DMF (38 ml) were added water(4 ml). The
mixture was stirred at 100 °C for 3 h. The reaction was cooled to room temperature.
Hydrochloric acid (1N) was added. The volume of HCl added was six times that of
DMF. After extracting by ethyl acetate, organic phase was washed by brine and dried
over anhydrous sodium sulfate. The solution was concentrated in vacuo to get D
(0.89g, 112%).
(E)Methyl 3-(4-hydroxyphenyl-1-propynyl) propanoate
Compound D (0.89g,4.3mmo)was dissolved in methanol(15ml), followed by adding
concentrated sulfuric acid(1.5ml) slowly with stirring. The mixture was stirred at
65°C for 12h. Water was added after removing most solvent. The emulsion was

extracted by AcOEt, which was washed with saturated brine and dried over anhydrous
sodium sulfate. After concentration in vacuo, it was purified by silica gel column
1
chromatography to afford the desired product E (0.83g.86.9%) as viscous liquid. H
NMR (300 MHz, DMSO-d6) δ 9.30 (s, 1H), 7.14 (d, J = 7.9 Hz, 2H), 6.70 (d, J = 7.9
Hz, 2H), 3.92 (s, 1H), 3.57 (s, 3H), 2.66 (d, J = 7.1 Hz, 2H), 1.77 (s, 3H).
General synthetic procedure for I from F using І-13 as an example.
(G)2-bromo-1-(2-ethoxyphenyl)ethanone
To a solution of 2-ethoxyacetophenone (4.71g, 28.7mmol) in AcOEt was added
copper bromide (7.37g, 31.6mmol). The solution was heated at 80°C under nitrogen
protection. When the solid in the flask turned from black to white, the solution was
cooled to room temperature. The solid was removed by filtration. The filter cake was
washed with AcOEt. The combined filtrates were concentrated in vacuo to afford G
(6.14g, 88.08%) which was used directly in the next step without purification.
(H) Methyl 2-(2-ethoxyphenyl)imidazo[1,2-a]pyridine-6-carboxylate
Sodium carbonate (0.96g, 9.06mmol) was added after dissolving 6-aminonicotinate
(1.5g, 9.96mmol) and G (2.2g, 9.06mmol) in ethanol. The mixture was stirred at 70°C
for 6 to 8 hours. The solvent was removed under reduced pressure. The residue was
added with water and ethyl acetate to dissolve. The extracts were combined and
washed by saturated brine. The organic phase was concentrated in vacuo after drying
over anhydrous sodium sulfate and purified by column chromatography to acquire
1
expected compound H as a yellow solid. Yield 1.13g, 42.16%. H NMR (300 MHz,
DMSO) δ 9.48 (s, 1H), 8.61 (s, 1H), 8.33 (d, J = 9.6 Hz, 1H), 7.63 (s, 2H), 7.33 (t, J =
9.1 Hz, 1H), 7.24 – 6.89 (m, 2H), 4.22 (q, J = 7.5 Hz, 2H), 3.91 (s, 3H), 1.56 (t, J =
7.4 Hz, 3H). 13C NMR (75 MHz, DMSO-d6) δ 165.56, 156.44, 144.31, 132.01,
129.58, 128.67, 124.23, 120.93, 116.26, 115.29, 114.45, 112.63, 64.21, 52.73, 15.26.
(I) (2-(2-ethoxyphenyl)imidazo[1,2-a]pyridine-6-)methanol
To a solution of H (0.69g, 2.33mmol) in dry THF was added LiAlH4 (0.3g,

7.93mmol) in batches at 0°C. After the reaction monitored by TLC was complete, a
large amount of ethyl acetate was added and stirred. The mixture was filtered through
diatomite, and the filter cake was washed with ethanol. The solvent was removed by
concentration under reduced pressure. Product I (1.12g) as a yellow solid was
obtained and used directly in the next step.
(J) 6-(Chloromethyl)-2-(2-ethoxyphenyl)imidazo[1, 2-a]pyridine
After dissolving I (1.12g, 4.17mmol) in DCM, thionyl chloride (0.99g, 8.34mmol)
was slowly added into the solution dropwise followed by stirring for 12h at room
temperature. The solution was quenched by saturated sodium bicarbonate solution,
and the pH was adjusted to 10 by adding 1N sodium hydroxide solution while stirring.
The mixture was then extracted by DCM followed by drying over anhydrous Na2SO4.
The organic solvent was concentrated in vacuo and the retained residue was purified
via column chromatography to afford J as a yellow solid (0.45g, 37.65%).
(K)Methyl3-(4-(2-(2-ethoxyphenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-
propynylpropanoate
To a solution of J (0.45g, 1.57mmol) and E (0.22g, 1.01mmol) in acetonitrile, Cs2CO3
(0.82g, 2.53mmol), catalytic amount of KI and benzyltriethylammonium chloride
were added. The mixture was stirred at 65°C for 8 hours. The solid was removed by
suction filtration, and the filter cake was washed with AcOEt. The filtrates were
combined and concentrated by rotary evaporator. The residue was purified by silica
gel column chromatography. Finally, a transparent viscous liquid K (83.2mg,
17.52%) was obtained.
(І-1)3-(4-(2-phenylimidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-propynylpropion
ic acid
1H NMR (300 MHz, DMSO-d6) δ 12.32 (s, 1H), 8.86 (s, 1H), 8.67 (s, 1H), 8.02 (d, J
= 7.3 Hz, 2H), 7.84 (d, J = 9.2 Hz, 1H), 7.69 (d, J = 9.2 Hz, 1H), 7.56 (t, J = 7.4 Hz,
2H), 7.46 (t, J = 7.2 Hz, 1H), 7.34 (d, J = 8.6 Hz, 2H), 7.05 (d, J = 8.6 Hz, 2H), 5.22

13
(s, 2H), 4.03 – 3.95 (m, 1H), 2.64 (d, J = 7.6 Hz, 2H), 1.81 (d, J = 2.3 Hz, 3H). C
NMR (75 MHz, DMSO-d6) δ 172.30, 157.31, 142.86, 141.26, 134.34, 131.99, 129.77,
129.53, 129.41, 128.91, 126.77, 126.33, 124.68, 115.71, 115.28, 115.12, 110.86,
81.06, 78.70, 66.91, 43.24, 33.12, 3.70.
(І-2)3-(4-(2-(4-ethylphenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-propyny
lpropionic acid
1H NMR (300 MHz, DMSO-d6) δ 12.35 (s, 1H), 8.67 (s, 1H), 8.41 (s, 1H), 7.91 (d, J
= 8.1 Hz, 2H), 7.62 (d, J = 9.3 Hz, 1H), 7.38 – 7.28 (m, 5H), 7.03 (d, J = 8.7 Hz, 2H),
5.13 (s, 2H), 3.99 (td, J = 7.3, 2.3 Hz, 1H), 2.71 – 2.59 (m, 4H), 1.81 (d, J = 2.3 Hz,
3H), 1.27 (d, J = 9.7 Hz, 3H). 13C NMR (75 MHz, DMSO-d6) δ 172.34, 157.44,
145.35, 144.80, 143.92, 141.79, 134.16, 133.68, 131.73, 128.86, 128.59, 126.07,
122.09, 116.90, 115.26, 81.06, 78.69, 36.52, 33.13, 28.70, 28.43, 16.01, 3.68.
(І-3)3-(4-(2-(4-fluorophenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-propyn
ylpropionic acid
1H NMR (300 MHz, DMSO) δ 8.85 (s, 1H), 8.63 (s, 1H), 8.06 (s, 2H), 7.85 (d, J = 9.1
Hz, 1H), 7.73 (d, J = 9.1 Hz, 1H), 7.40 (d, J = 8.1 Hz, 2H), 7.33 (d, J = 9.2 Hz, 2H),
7.03 (d, J = 7.3 Hz, 2H), 5.22 (s, 2H), 3.98 (s, 1H), 2.62 (d, J = 6.8 Hz, 2H), 1.79 (s,
3H). 13C NMR (75 MHz, DMSO-d6) δ 172.30, 157.26, 142.21, 139.25, 134.39,
130.64, 128.92, 128.75, 128.64, 126.98, 125.31, 116.80, 116.52, 115.27, 114.45,
111.00, 81.05, 78.69, 66.76, 43.23, 33.11, 3.68.
(І-4)3-(4-(2-(4-isopropylphenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-pro
pynylpropionic acid
1H NMR (300 MHz, DMSO-d6) δ 12.31 (s, 1H), 8.74 (s, 1H), 8.49 (s, 1H), 7.91 (d, J
= 8.2 Hz, 2H), 7.71 (d, J = 9.3 Hz, 1H), 7.48 (d, J = 9.4 Hz, 1H), 7.36 (dd, J = 13.7,
8.5 Hz, 4H), 7.04 (d, J = 8.7 Hz, 2H), 5.17 (s, 2H), 3.97 (tdt, J = 6.2, 4.3, 1.7 Hz, 1H),
2.96 (p, J = 6.8 Hz, 1H), 2.63 (d, J = 7.6 Hz, 2H), 1.80 (d, J = 2.4 Hz, 3H), 1.27 (s,
13
3H), 1.25 (s, 3H). C NMR (75 MHz, DMSO-d6) δ 172.30, 157.39, 148.97, 143.90,

134.22, 131.45, 128.87, 127.23, 126.30, 126.16, 115.27, 109.85, 81.07, 78.68, 66.81,
43.23, 33.73, 24.27, 3.70.
(І-5)
3-(4-(2-(3-methylphenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-propynylp
ropionic acid
1H NMR (400 MHz, DMSO-d6) δ 12.27 (s, 1H), 8.64 (s, 1H), 8.40 (s, 1H), 7.87 –
7.72 (m, 2H), 7.60 (d, J = 9.3 Hz, 1H), 7.37 – 7.27 (m, 4H), 7.14 (d, J = 7.4 Hz, 1H),
7.01 (d, J = 8.6 Hz, 2H), 5.10 (s, 2H), 3.97 (dt, J = 7.3, 3.6 Hz, 1H), 2.62 (d, J = 7.6
13
Hz, 2H), 2.38 (s, 3H), 1.79 (d, J = 2.2 Hz, 3H). C NMR (75 MHz, DMSO-d6) δ
172.33, 157.44, 145.27, 144.77, 138.25, 134.16, 129.09, 128.86, 126.64, 126.16,
123.21, 122.18, 116.96, 115.25, 109.93, 81.07, 78.68, 67.29, 37.90, 33.14, 21.58,
3.69.
(І-6)
3-(4-(2-(2-methylphenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-propynylp
ropionic acid
1H NMR (300 MHz, DMSO) δ 12.27 (s, 1H), 8.68 (s, 1H), 8.23 (s, 1H), 7.99 – 7.86
(m, 1H), 7.63 (d, J = 9.3 Hz, 1H), 7.38 – 7.20 (m, 6H), 7.00 (t, J = 9.1 Hz, 2H), 5.12
(s, 2H), 3.97 (td, J = 7.6, 2.5 Hz, 1H), 2.61 (d, J = 7.6 Hz, 2H), 2.55 (s, 3H), 1.78 (d, J
= 2.2 Hz, 3H). 13C NMR (75 MHz, DMSO-d6) δ 172.33, 157.41, 144.80, 143.89,
135.63, 134.15, 131.39, 129.42, 128.86, 127.91, 126.36, 126.06, 125.99, 121.96,
116.98, 115.24, 112.39, 78.67, 67.31, 43.24, 33.13, 22.06, 3.69.
(І-7)
3-(4-(2-(4-methylphenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-propynylp
ropionic acid
1H NMR (300 MHz, DMSO) δ 7.63 (s, 1H), 7.54 (d, J = 8.1 Hz, 2H), 7.49 (d, J = 8.4
Hz, 1H), 7.44 – 7.22 (m, 4H), 6.76 – 6.66 (m, 1H), 6.43 (dd, J = 13.9, 2.6 Hz, 1H),

6.28 (d, J = 7.1 Hz, 1H), 6.04 (t, J = 6.4 Hz, 1H), 4.25 (d, J = 5.3 Hz, 2H), 3.98 (s,
2H), 2.51 (s, 3H), 2.34 (s, 3H). 13C NMR (75 MHz, DMSO-d6) δ 172.33, 157.40,
146.10, 144.39, 137.78, 135.71, 134.16, 130.88, 129.83, 128.87, 126.70, 126.21,
126.00, 115.23, 109.69, 81.06, 78.67, 33.11, 29.21, 3.70.
(І-8)
3-(4-(2-(4-Trifluoromethylphenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-p
ropynylpropionic acid
1H NMR (300 MHz, DMSO) δ 12.23 (s, 1H), 8.69 (s, 1H), 8.59 (s, 1H), 8.19 (d, J =
8.0 Hz, 2H), 7.81 (d, J = 8.3 Hz, 2H), 7.65 (d, J = 9.3 Hz, 1H), 7.43 – 7.23 (m, 3H),
7.01 (d, J = 8.6 Hz, 2H), 5.12 (s, 2H), 3.96 (td, J = 7.4, 2.5 Hz, 1H), 2.61 (d, J = 7.5
Hz, 2H), 1.78 (d, J = 2.1 Hz, 3H). 13C NMR (101 MHz, DMSO-d6) δ 172.30, 157.31,
134.28, 128.88, 126.74, 126.66, 126.34, 116.06, 115.25, 111.98, 81.03, 66.97, 46.57,
43.23, 33.12, 3.67.
(І-9)
3-(4-(2-(2,4-dimethylphenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-propyn
ylpropionic acid
1H NMR (300 MHz, DMSO-d6) δ 12.31 (s, 1H), 8.77 (s, 1H), 8.30 (s, 1H), 7.74 (t, J
= 7.1 Hz, 2H), 7.53 (d, J = 8.7 Hz, 1H), 7.32 (d, J = 7.3 Hz, 2H), 7.14 (d, J = 8.7 Hz,
2H), 7.01 (d, J = 7.4 Hz, 2H), 5.17 (s, 2H), 3.97 (s, 1H), 2.61 (d, J = 6.7 Hz, 2H), 2.32
(s, 3H), 1.78 (s, 3H). 13C NMR (75 MHz, DMSO-d6) δ 172.27, 157.34, 142.46,
138.11, 135.85, 134.31, 132.17, 129.54, 128.89, 127.21, 126.36, 123.63, 115.48,
115.29, 112.60, 67.10, 43.25, 33.13, 21.69, 21.19, 3.70.
(І-10)
3-(4-(2-(2-fluorophenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-propynylpr
opionic acid

1H NMR (400 MHz, DMSO-d6) δ 8.64 (s, 1H), 8.37 (s, 1H), 8.05 – 7.76 (m, 2H),
7.60 (d, J = 7.6 Hz, 1H), 7.30 (s, 5H), 7.02 (s, 2H), 5.11 (s, 2H), 4.12 – 3.92 (m, 1H),
3.58 (s, 3H), 2.81 – 2.63 (m, 2H), 1.90 – 1.66 (m, 7H), 1.42 (q, J = 12.7 Hz, 4H). 13C
NMR (101 MHz, DMSO-d6) δ 172.24, 157.22, 141.58, 134.44, 128.92, 127.04,
125.70, 116.96, 115.30, 114.20, 114.06, 81.04, 78.69, 43.24, 33.13, 29.49, 3.73.
(І-11)
3-(4-(2-(4-cyclohexylphenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-propyn
ylpropionic acid
1H NMR (300 MHz, DMSO) δ 12.26 (s, 1H), 8.73 (s, 1H), 8.38 – 8.23 (m, 2H), 7.64
(d, J = 9.3 Hz, 1H), 7.45 – 7.27 (m, 4H), 7.22 (td, J = 8.6, 2.5 Hz, 1H), 7.01 (d, J =
8.7 Hz, 2H), 5.11 (s, 2H), 3.96 (td, J = 7.4, 2.3 Hz, 1H), 2.61 (d, J = 7.6 Hz, 2H), 1.78
(d, J = 2.3 Hz, 3H). 13C NMR (75 MHz, DMSO-d6) δ 171.27, 157.50, 147.76, 144.73,
133.80, 131.79, 131.05, 128.85, 127.48, 126.09, 122.14, 116.85, 115.29, 110.78,
109.55, 80.63, 79.01, 51.88, 44.06, 42.80, 34.37, 33.09, 26.83, 3.65.
(І-12)
3-(4-(2-(2,4-difluorophenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-propyn
ylpropionic acid
1H NMR (300 MHz, DMSO) δ 12.26 (s, 1H), 8.73 (s, 1H), 8.38 – 8.23 (m, 2H), 7.64
(d, J = 9.3 Hz, 1H), 7.45 – 7.27 (m, 4H), 7.22 (td, J = 8.6, 2.5 Hz, 1H), 7.01 (d, J =
8.7 Hz, 2H), 5.11 (s, 2H), 3.96 (td, J = 7.4, 2.3 Hz, 1H), 2.61 (d, J = 7.6 Hz, 2H), 1.78
(d, J = 2.3 Hz, 3H). 13C NMR (101 MHz, DMSO-d6) δ 172.32, 157.41, 144.20,
137.89, 134.19, 130.04, 128.85, 126.73, 126.31, 122.28, 116.95, 115.23, 112.82,
112.62, 112.41, 104.85, 67.30, 43.24, 33.13, 3.67.
(І-13)
3-(4-(2-(2-ethoxyphenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-propynylpr
opionic acid

After dissolving K (83mg, 0.177mmol) in a mixed solvent (THF: CH3OH: H2O=3: 1:
3), it was added LiOH (11mg, 0.443mmol) and stirred at room temperature. The
solution changed from light yellow to orange. After the raw material was monitored to
be reacted completely, the most organic solvent was removed under reduced pressure.
Adjust the pH to 5-6 with 1N of hydrochloric acid, and white solid precipitated. After
suction filtration, the filter cake was washed with water, and the filter cake was dried
in a ventilated place. Purification by silica gel column chromatography gave a white
powdery solid І-13. Yield 71mg, 88.18%. 1H NMR (300 MHz, DMSO-d6) δ 12.30 (s,
1H), 8.93 (s, 1H), 8.53 (s, 1H), 8.29 – 8.20 (m, 1H), 7.74 (d, J = 9.1 Hz, 1H), 7.55 (d,
J = 9.3 Hz, 1H), 7.43 – 7.31 (m, 3H), 7.20 (d, J = 8.2 Hz, 1H), 7.12 (t, J = 7.4 Hz, 1H),
7.05 (d, J = 8.6 Hz, 2H), 5.18 (s, 2H), 4.27 (q, J = 6.9 Hz, 2H), 3.99 (ddt, J = 9.9, 4.9,
2.2 Hz, 1H), 2.64 (d, J = 7.6 Hz, 2H), 1.81 (d, J = 2.3 Hz, 3H), 1.56 (t, J = 6.9 Hz,
3H). 13C NMR (75 MHz, DMSO-d6) δ 172.34, 157.38, 156.24, 142.34, 141.52,
134.25, 130.01, 128.90, 128.43, 128.23, 126.74, 123.60, 123.25, 121.03, 120.29,
117.47, 115.27, 113.65, 112.82, 81.05, 78.70, 33.12, 31.77, 29.50, 15.21, 15.15, 3.70.
(І-14)
3-(4-(2-(4-methoxyphenyl)imidazo[1,2-a]pyridine-6-)methoxy)phenyl-3-propynyl
propionic acid
1H NMR (300 MHz, DMSO) δ 12.23 (s, 1H), 8.83 (s, 1H), 8.55 (s, 1H), 7.95 (d, J =
8.2 Hz, 2H), 7.82 (d, J = 8.8 Hz, 1H), 7.69 (d, J = 8.3 Hz, 1H), 7.32 (d, J = 8.1 Hz,
2H), 7.10 (d, J = 8.0 Hz, 2H), 7.02 (d, J = 7.8 Hz, 3H), 5.20 (s, 2H), 4.01 – 3.93 (m,
1H), 2.62 (d, J = 6.9 Hz, 2H), 1.78 (s, 3H), 1.24 (s, 3H). 13C NMR (75 MHz,
DMSO-d6) δ 172.29, 160.55, 157.27, 141.99, 134.38, 128.91, 127.94, 126.82, 125.12,
122.40, 115.27, 115.04, 109.93, 81.06, 78.70, 66.82, 55.82, 43.25, 33.12, 3.71.
(ІІ-1)
3-(4-(2-phenylimidazo[1,2-a]pyridin-7-)methoxy)phenyl-3-propynylpropionic
acid

1H NMR (400 MHz, DMSO) δ 12.27 (s, 1H), 8.53 (d, J = 7.0 Hz, 1H), 8.41 (s, 1H),
7.97 (d, J = 7.6 Hz, 2H), 7.63 (s, 1H), 7.51 – 7.39 (m, 2H), 7.32 (dd, J = 14.1, 7.8 Hz,
3H), 7.01 (d, J = 8.4 Hz, 2H), 6.95 (dd, J = 7.0, 1.6 Hz, 1H), 5.17 (s, 2H), 4.00 – 3.90
13
(m, 1H), 2.61 (d, J = 7.6 Hz, 2H), 1.78 (d, J = 2.4 Hz, 3H). C NMR (101 MHz,
DMSO-d6) δ 172.26, 145.21, 145.07, 135.11, 134.31, 134.18, 129.16, 128.84, 128.18,
127.30, 126.02, 115.30, 114.84, 112.33, 109.65, 81.06, 78.67, 68.67, 43.25, 33.16,
3.67.
(ІІ-2)
3-(4-(2-(2,4-dimethylphenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-propyn
ylpropionic acid
1H NMR (400 MHz, DMSO-d6) δ 12.25 (s, 1H), 8.54 (d, J = 6.9 Hz, 1H), 8.16 (s,
1H), 7.82 (d, J = 7.7 Hz, 1H), 7.63 (s, 1H), 7.30 (d, J = 8.6 Hz, 2H), 7.10 (d, J = 9.9
Hz, 2H), 7.01 (d, J = 8.6 Hz, 2H), 6.97 – 6.91 (m, 1H), 5.17 (s, 2H), 3.96 (dt, J = 7.5,
3.7 Hz, 1H), 2.61 (d, J = 7.6 Hz, 2H), 2.51 (s, 3H), 2.31 (s, 3H), 1.78 (d, J = 2.3 Hz,
3H). 13C NMR (101 MHz, DMSO-d6) δ 172.30, 157.32, 144.84, 144.00, 137.04,
135.39, 134.93, 134.15, 132.02, 130.78, 129.40, 128.85, 127.18, 127.03, 115.28,
114.70, 112.05, 111.69, 68.65, 43.25, 33.14, 21.98, 21.15, 3.69.
(ІІ-3)
3-(4-(2-(4-ethylphenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-propynylpro
pionic acid
1H NMR (400 MHz, DMSO-d6) δ 12.27 (s, 1H), 8.52 (s, 1H), 8.35 (s, 1H), 8.04 –
7.79 (m, 2H), 7.62 (s, 1H), 7.30 (s, 4H), 7.15 – 6.87 (m, 3H), 5.17 (s, 2H), 4.07 – 3.86
(m, 1H), 2.56 – 2.40 (m, 2H), 1.78 (s, 3H), 1.35 – 1.12 (m, 5H). 13C NMR (75 MHz,
DMSO-d6) δ 172.35, 157.28, 144.98, 144.83, 143.99, 141.26, 134.13, 128.87, 128.62,
127.31, 126.05, 115.26, 114.55, 112.42, 109.34, 81.06, 78.70, 43.20, 28.43, 16.02,
3.68.
(ІІ-4)

3-(4-(2-(2-fluorophenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-propynylpr
opionic acid
1H NMR (300 MHz, DMSO) δ 12.24 (s, 1H), 8.61 (d, J = 7.0 Hz, 1H), 8.35 (d, J = 4.3
Hz, 1H), 8.27 (td, J = 7.6, 1.6 Hz, 1H), 7.66 (s, 1H), 7.44 – 7.24 (m, 5H), 6.99 (dd, J =
10.0, 4.9 Hz, 3H), 5.18 (s, 2H), 3.95 (s, 1H), 2.61 (d, J = 7.6 Hz, 2H), 1.78 (d, J = 2.3
13
Hz, 3H). C NMR (101 MHz, DMSO-d6) δ 172.28, 157.28, 144.18, 136.17, 134.21,
129.81, 128.86, 127.64, 125.26, 116.47, 116.25, 115.27, 114.42, 113.07, 112.93,
112.62, 81.06, 78.67, 68.55, 43.24, 33.14, 3.69.
(ІІ-5)
3-(4-(2-(4-isopropylphenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-propyny
lpropionic acid
1H NMR (400 MHz, DMSO-d6) δ 12.27 (s, 1H), 8.63 – 8.24 (m, 2H), 8.03 – 7.76 (m,
2H), 7.76 – 7.53 (m, 1H), 7.31 (s, 3H), 7.16 – 6.81 (m, 3H), 5.17 (s, 2H), 4.08 – 3.85
13
(m, 1H), 3.05 – 2.79 (m, 1H), 2.70 – 2.55 (m, 2H), 1.78 (s, 3H), 1.24 (s, 6H). C
NMR (75 MHz, DMSO-d6) δ 172.36, 157.29, 148.54, 144.91, 135.10, 134.13, 131.78,
128.87, 127.27, 127.13, 126.05, 115.26, 112.34, 109.29, 81.06, 78.68, 43.21, 33.70,
24.30, 3.68.
(ІІ-6)
3-(4-(2-(4-cyclohexylphenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-propyn
ylpropionic acid
1H NMR (400 MHz, DMSO) δ 12.28 (s, 1H), 8.82 (d, J = 6.6 Hz, 1H), 8.70 (s, 1H),
8.01 – 7.84 (m, 3H), 7.42 (d, J = 7.7 Hz, 3H), 7.32 (d, J = 8.2 Hz, 2H), 7.03 (d, J =
8.2 Hz, 2H), 5.35 (s, 2H), 3.97 (t, J = 8.0 Hz, 1H), 2.62 (d, J = 7.5 Hz, 2H), 1.88 –
1.69 (m, 7H), 1.52 – 1.32 (m, 4H), 1.31 – 1.18 (m, 3H). 13C NMR (101 MHz,
DMSO-d6) δ 172.23, 157.01, 150.08, 134.57, 129.03, 128.97, 128.07, 126.66, 115.76,
115.30, 110.80, 110.04, 81.03, 78.71, 68.00, 44.07, 43.23, 34.17, 33.12, 26.75, 26.01,
3.70.

(ІІ-7)
3-(4-(2-(2,4-difluorophenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-propyn
ylpropionic acid
1H NMR (300 MHz, DMSO) δ 12.25 (s, 1H), 8.61 (d, J = 7.0 Hz, 1H), 8.37 – 8.22 (m,
2H), 7.65 (s, 1H), 7.39 (ddd, J = 11.7, 9.4, 2.4 Hz, 1H), 7.30 (d, J = 8.6 Hz, 2H), 7.22
(td, J = 8.5, 2.2 Hz, 1H), 7.01 (dd, J = 5.1, 3.5 Hz, 3H), 5.18 (s, 2H), 3.95 (td, J = 7.3,
2.3 Hz, 1H), 2.61 (d, J = 7.6 Hz, 2H), 1.78 (d, J = 2.2 Hz, 3H). 13C NMR (101 MHz,
DMSO-d6) δ 172.31, 157.27, 144.32, 137.68, 135.93, 134.18, 130.05, 128.85, 127.59,
115.25, 114.55, 112.51, 112.42, 104.86, 81.05, 78.66, 68.52, 43.22, 33.13, 3.67.
(ІІ-8)
3-(4-(2-(4-methylphenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-propynylp
ropionic acid
1H NMR (300 MHz, DMSO) δ 12.26 (s, 1H), 8.50 (d, J = 6.9 Hz, 1H), 8.34 (s, 1H),
7.85 (d, J = 7.7 Hz, 2H), 7.61 (s, 1H), 7.27 (dd, J = 13.7, 8.1 Hz, 4H), 7.00 (d, J = 8.2
Hz, 2H), 6.93 (d, J = 6.7 Hz, 1H), 5.16 (s, 2H), 3.95 (s, 1H), 2.61 (d, J = 7.4 Hz, 2H),
13
2.34 (s, 3H), 1.78 (s, 3H). C NMR (75 MHz, DMSO-d6) δ 172.38, 157.29, 145.12,
144.90, 137.61, 135.17, 134.13, 131.30, 129.79, 128.86, 127.25, 125.97, 115.26,
114.59, 112.35, 109.26, 81.04, 78.70, 49.07, 43.22, 33.13, 21.31, 3.66.
(ІІ-9)
3-(4-(2-(2-methylphenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-propynylp
ropionic acid
1H NMR (300 MHz, DMSO) δ 8.56 (d, J = 7.0 Hz, 1H), 8.20 (s, 1H), 7.96 – 7.87 (m,
1H), 7.64 (s, 1H), 7.29 (t, J = 6.7 Hz, 5H), 6.98 (dd, J = 14.5, 7.2 Hz, 3H), 5.18 (s,
2H), 3.95 (td, J = 7.3, 2.2 Hz, 1H), 2.60 (d, J = 7.6 Hz, 2H), 2.54 (s, 3H), 1.78 (d, J =
2.2 Hz, 3H). 13C NMR (101 MHz, DMSO-d6) δ 172.32, 157.31, 145.29, 137.49,
134.94, 134.13, 131.49, 129.75, 128.84, 127.20, 125.95, 115.25, 114.73, 112.24,
109.20, 81.05, 78.66, 68.61, 43.24, 33.14, 21.32, 3.67.

(ІІ-10)
3-(4-(2-(3-methylphenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-propynylp
ropionic acid
1H NMR (300 MHz, DMSO-d6) δ 8.73 (d, J = 6.9 Hz, 1H), 8.63 (s, 1H), 7.81 (t, J =
8.6 Hz, 3H), 7.41 (t, J = 7.6 Hz, 1H), 7.36 – 7.21 (m, 4H), 7.02 (d, J = 8.3 Hz, 2H),
13
5.29 (s, 2H), 3.97 (s, 1H), 2.61 (d, J = 7.5 Hz, 2H), 2.39 (s, 3H), 1.78 (s, 3H). C
NMR (75 MHz, DMSO-d6) δ 172.35, 157.05, 142.37, 140.58, 139.81, 138.85, 134.40,
130.38, 129.78, 129.49, 128.95, 128.53, 126.87, 123.52, 115.24, 114.76, 111.37,
110.74, 81.02, 78.73, 68.09, 43.21, 33.11, 21.49, 3.68.
(ІІ-11)
3-(4-(2-(4-Trifluoromethylphenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-p
ropynylpropionic acid
1H NMR (300 MHz, DMSO) δ 8.56 (d, J = 5.4 Hz, 2H), 8.18 (d, J = 8.0 Hz, 2H), 7.80
(d, J = 8.2 Hz, 2H), 7.66 (s, 1H), 7.30 (d, J = 8.4 Hz, 2H), 7.00 (d, J = 8.6 Hz, 3H),
13
5.18 (s, 2H), 2.60 (d, J = 7.5 Hz, 2H), 1.77 (d, J = 1.5 Hz, 3H). C NMR (75 MHz,
DMSO-d6) δ 172.32, 157.26, 145.20, 135.91, 134.18, 128.85, 127.57, 126.48, 126.15,
115.24, 114.83, 112.77, 111.15, 81.02, 78.66, 68.49, 43.21, 33.12, 3.64.
(ІІ-12)
3-(4-(2-(4-fluorophenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-propynylpr
opionic acid
1H NMR (300 MHz, DMSO) δ 8.52 (d, J = 6.9 Hz, 1H), 8.38 (s, 1H), 8.00 (dd, J = 8.5,
5.7 Hz, 2H), 7.62 (s, 1H), 7.28 (dd, J = 10.5, 8.8 Hz, 4H), 7.00 (d, J = 8.6 Hz, 2H),
6.95 (d, J = 7.0 Hz, 1H), 5.17 (s, 2H), 3.96 (dd, J = 8.5, 6.2 Hz, 1H), 2.60 (d, J = 7.6
Hz, 2H), 1.77 (d, J = 2.1 Hz, 3H). 13C NMR (75 MHz, DMSO-d6) δ 172.41, 160.71,
157.26, 145.04, 144.15, 135.36, 134.13, 130.70, 128.87, 128.03, 127.92, 127.34,
116.23, 115.94, 115.24, 114.65, 112.45, 109.54, 81.03, 78.71, 68.52, 33.12, 31.96,
3.65.

(ІІ-13)
3-(4-(2-(2,5-difluorophenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-propyn
ylpropionic acid
1H NMR (300 MHz, DMSO-d6) δ 8.78 (d, J = 6.9 Hz, 1H), 8.60 (d, J = 3.6 Hz, 1H),
8.10 – 7.99 (m, 1H), 7.82 (s, 1H), 7.52 (td, J = 10.2, 9.7, 4.6 Hz, 1H), 7.36 (dd, J =
14.5, 6.4 Hz, 3H), 7.27 (d, J = 7.1 Hz, 1H), 7.04 (d, J = 8.7 Hz, 2H), 5.30 (s, 2H),
13
4.03 – 3.95 (m, 1H), 2.63 (d, J = 7.6 Hz, 2H), 1.79 (dd, J = 7.7, 2.3 Hz, 3H). C
NMR (75 MHz, DMSO-d6) δ 172.34, 157.10, 142.78, 140.00, 134.38, 133.88, 128.94,
128.48, 115.57, 115.26, 114.32, 112.30, 81.03, 78.71, 43.20, 33.10, 3.68.
(ІІ-14)
3-(4-(2-(2-ethoxyphenyl)imidazo[1,2-a]pyridine-7-)methoxy)phenyl-3-propynylpr
opionic acid
1H NMR (300 MHz, DMSO-d6) δ 12.28 (s, 1H), 8.70 – 8.63 (m, 1H), 8.40 (s, 1H),
8.32 (dd, J = 7.7, 1.7 Hz, 1H), 7.63 (s, 1H), 7.31 (td, J = 6.3, 5.5, 3.1 Hz, 3H), 7.14 (d,
J = 7.9 Hz, 1H), 7.11 – 6.99 (m, 3H), 6.94 (dd, J = 7.0, 1.5 Hz, 1H), 5.19 (s, 2H), 4.24
(q, J = 6.9 Hz, 2H), 3.97 (td, J = 7.5, 2.3 Hz, 1H), 2.63 (d, J = 7.6 Hz, 2H), 1.80 (d, J
13
= 2.4 Hz, 3H), 1.56 (t, J = 6.9 Hz, 3H). C NMR (75 MHz, DMSO-d6) δ 172.46,
157.34, 156.31, 142.93, 139.06, 134.34, 129.88, 129.00, 128.00, 127.60, 121.09,
115.36, 114.81, 114.47, 113.39, 112.94, 81.16, 78.80, 68.55, 64.33, 43.34, 33.23,
15.31, 3.78.
4.2 Molecular docking
Schrödinger software was used for docking simulation based on the crystal
structure of GPR40 (PDB ID: 4PHU). Other ligands and water were removed during
this process, and the TAK-875 binding site was selected to be docked within a
distance of 5 Å. According to the comparison of docking scores, the optimal docking
method and conformation were selected and compared with those for TAK-875.

4.3 Animals and statistical analysis
Eight-week-old male SD(Sprague-Dawley) rats, 10-week-old ICR(Institute of
Cancer Research) mice (male) and 10-week-old C57BL/6 mice (male) were
purchased from the Qinglongshan animal breeding ground in Nanjing. Adaptive feed
was performed for a week. The animal room was kept under the conditions of a
constant 12-hour light/black cycle at 23 ± 2℃ with a humidity of 50 ± 10%. Animals
were kept free to eat. All animal experimental programs were verified by the Ethics
Committee of China Pharmaceutical University (CPU). They were conducted on the
basis of the Chinese Laboratory Animal Management Regulations and in accordance
with the National Institutes of Health's Guide to the Care and Use of Laboratory
Animals. GraphPad Prism 5 was used to perform statistical analysis which was
analyzed by one-way ANOVA and Tukey's multiple comparison post hoc tests.
4.4 Pharmacokinetic study
Male Sprague-Dawley rats weighing 180-220 g were fasted for 12 h. They were
randomly grouped (4 in each group). After oral administration (I-14, 10mg/kg), blood
samples were taken at 5 min, 15 min, 30 min, 45 min and 1 h, 2 h, 4 h, 6 h, 8 h, 12 h,
24 h. The blood was placed in a centrifuge tube containing heparin, centrifuged at
8000 rpm/min for 10 min to separate plasma. Plasma (50μl) was taken separately.
Internal standard(TAK-875) (50μl) and 200μl of methanol solution containing 1%
formic acid were added. After mixing, the mixture was centrifuged at 14,000 rpm/min
for 15 min twice. The supernatant (3μl) was taken, and the mass spectral response
peak area of the compound was analyzed by LC-MS/MS. The concentration of the
compound(I-14) was calculated using a standard curve. The relevant pharmacokinetic
parameters were calculated using DAS V2.1.
4.5 OGTT in normoglycemic ICR mice
ICR mice were fasted for 12 h, weighted, and randomized into 5 groups (n=6 per
group). After administrating orally with vehicle, TAK-875 (30 mg/kg), compound