Design, synthesis and application of new bile acid ligands with 1,2,3-triazole ring

Article abstract of DOI:10.1080/10610278.2016.1175568

New dimers have been obtained from propargyl ester of bile acids and α,α′-diazide-m-xylene by intermolecular 1,3-dipolar cycloaddition. These compounds have been used as ligands to form intermolecular hydrogen bonds with various aromatic acids. The struct

Full text of DOI:10.1080/10610278.2016.1175568

Supramolecular Chemistry
ISSN: 1061-0278 (Print) 1029-0478 (Online) Journal homepage: http://www.tandfonline.com/loi/gsch20
Design, synthesis and application of new bile acid
ligands with 1,2,3-triazole ring
Tomasz Pospieszny, Marta Pakiet, Iwona Kowalczyk & Bogumił Brycki
To cite this article: Tomasz Pospieszny, Marta Pakiet, Iwona Kowalczyk & Bogumił Brycki
(2016): Design, synthesis and application of new bile acid ligands with 1,2,3-triazole ring,
Supramolecular Chemistry, DOI: 10.1080/10610278.2016.1175568
To link to this article: http://dx.doi.org/10.1080/10610278.2016.1175568
Published online: 28 Apr 2016.
Submit your article to this journal
Article views: 5
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=gsch20
Download by: [Florida Atlantic University]
Date: 04 May 2016, At: 01:36

Supramolecular chemiStry, 2016
http://dx.doi.org/10.1080/10610278.2016.1175568
Design, synthesis and application of new bile acid ligands with 1,2,3-triazole ring
Tomasz Pospieszny, Marta Pakiet, Iwona Kowalczyk and Bogumił Brycki
laboratory of microbiocides chemistry, Faculty of chemistry, adam mickiewicz university, poznań, poland
ARTICLE HISTORY
ABSTRACT
received 22 December 2015
accepted 3 april 2016
New dimers have been obtained from propargyl ester of bile acids and α,α′-diazide-m-xylene by
intermolecular 1,3-dipolar cycloaddition. These compounds have been used as ligands to form
intermolecular hydrogen bonds with various aromatic acids. The structures of all products were
confirmed by spectroscopic (1H NMR, 13C NMR and FT-IR) analysis, mass spectrometry (ESI, MALDI)
and PM5 semiempirical methods.
KEYWORDS
Bile acids; click chemistry;
1,2,3-triazole ring, hydrogen
bonds
The modification of bile acids by the ‘click chemistry’
allows to synthesise novel conjugates with a variety of
applications (18). K. B. Sharpless was the first to describe
copper-catalysed azide–alkyne cycloaddition (CuAAC). It
is one of the most important reactions in organic, material
and polymer chemistry, and especially in bioconjugation
reactions (18, 19). The ‘click chemistry’ creates a broad
spectrum of rings with carbon–heteroatom bonds. These
simple reaction conditions are characterised by high selec-
tivity and productivity as well as an easy way of product
isolation. Products are resistant to metabolic processes.
They are also stable in various solvents, including water
(19–22). Especially important is the 1,3-dipolar cycloaddi-
tion between terminal alkynes and azides in the presence
of copper(I) catalyst known as Huisgen reaction (23, 24).
The copper(I)-catalysed ‘click’ reaction is an immensely
useful synthetic way to obtaining 1,2,3-triazole derivatives
1. Introduction
The major metabolites of cholesterol are polyhydroxylated
steroidal acids commonly known as bile acids. These com-
pounds are conjugated with taurine or glycine in the liver,
forming bile salts. Bile acids reduce the surface tension
of solutions and activate digestive enzymes (1–5). They
possess a rigid, large, curved skeleton where two rings
A/B have a cis geometry. Bile acids have chemically differ-
ent polar hydroxyl groups 3α; 3α,7α; 3α,12α; or 3α,7α,12α
which are responsible to some extent for their amphiphilic
properties. All of these attributes make bile acids and their
modified derivatives very interesting starting materials for
the synthesis of macrocyclic molecular dimers, molecular
tweezers or cholaphanes (6–9). On the other hand, bile
acid dimers can be used for the synthesis of macrocyclic
compounds as artificial receptors with good organogeling
properties (10–17).
CONTACT tomasz pospieszny
tposp@amu.edu.pl
© 2016 informa uK limited, trading as taylor & Francis Group

2
T. POSPIESzNy ET AL.
of bile acids (23–33). The regioselective of cycloaddition
reactions depends on catalysts and temperatures. The
1,5-disubstituted 1,2,3-triazoles are formed in the pres-
ence of catalysts containing ruthenium(II); on the other
hand, 1,4-disubstituted 1,2,3-triazoles are obtained in the
presence of catalysts containing copper(I) (34, 35). These
five-membered heterocyclic rings can form intra- and
intermolecular hydrogen bonds together with dipole–
dipole interactions with an increase in the solubility of
conjugates and facilitate binding of molecular targets (36).
over anhydrous Na2SO4. The crude compound was puri-
fied by column chromatography on silica gel using CHCl3/
AcOEt (50:1) as an eluent.
Procedure for compound (12): Propargyl deoxycholate
(345 mg, 0.8 mmol) was dissolved in a mixture of t-butanol/
methanol (6 mL, 5:1), and 1,3-di(azidomethyl)benzene
(75 mg, 0.4 mmol) was added. Next, to the homogenous
mixture were added CuSO4·5H2O (3 mg, 3 mol%) and
sodium ascorbate (9 mg, 20 mol%) in water (0.3 mL). The
reaction mixture was heated at 60 °C for 5 h and then
extracted with chloroform, washed with brine and dried
over anhydrous Na2SO4. The crude compound was puri-
fied by column chromatography on silica gel using CHCl3/
AcOEt (10:1) as an eluent.
2. Experimental
2.1. Chemicals and instruments
Procedure for compound (13): Propargyl cholate
(360 mg, 0.8 mmol) dissolved in a mixture of t-butanol/
methanol (6 mL, 5:1), and 1,3-di(azidomethyl)benzene
(75 mg, 0.4 mmol) was added to. Next, to the homoge-
nous mixture were added CuSO4·5H2O (3 mg, 3 mol%)
and sodium ascorbate (9 mg, 20 mol%) in water (0.3 mL).
The reaction mixture was heated at 60 °C for 5 h and then
extracted with chloroform, washed with brine and dried
over anhydrous Na2SO4. The crude compound was puri-
fied by column chromatography on silica gel using CHCl3/
MeOH (20:1) as an eluent.
Procedure for compound (14): Compound (9) (330 mg,
0.62 mmol) was dissolved in a mixture of t-butanol/metha-
nol (6 mL, 5:1). Then, corresponding amounts of 1,3-di(azi-
domethyl)benzene were added (58 mg, 0.31 mmol). Next,
to the homogenous mixture were added CuSO4·5H2O
(3 mg, 3 mol%) and sodium ascorbate (9 mg, 20 mol%) in
water (0.3 mL). The reaction mixture was heated at 60 °C
for 8 h and then extracted with chloroform, washed with
brine and dried over anhydrous Na2SO4. The crude com-
pound was purified by column chromatography on silica
gel using CHCl3/AcOEt (5:1) as an eluent.
Procedure for compound (15): Compound (10) (500 mg,
0.91 mmol) was dissolved in a mixture of t-butanol/metha-
nol (6 mL, 5:1). Then, corresponding amounts of 1,3-di(azi-
domethyl)benzene were added (85 mg, 0.45 mmol). Next,
to the homogenous mixture were added CuSO4·5H2O
(3 mg, 3 mol%) and sodium ascorbate (9 mg, 20 mol%) in
water (0.3 mL). The reaction mixture was heated at 60 °C
for 8 h and then extracted with chloroform, washed with
brine and dried over anhydrous Na2SO4. The crude com-
pound was purified by column chromatography on silica
gel using CHCl3/AcOEt (5:1) as an eluent.
Compound (11). yield 70%. (280 mg).m.p. 145–149 °C.
FT-IR (KBr) νmax: 3414, 2931, 2862, 1737, 1449, 1161, 753.
1H NMR (CDCl3): δ 7.55 (s, 2H, CH-triazole ring), 7.27–7.22
(m, 4H, Ar–H), 5.51 (s, 4H, Ph–CH2–triazole ring), 5.19 (s,
4H, O–CH2–triazole ring), 3.67–3.57 (m, 2H, 3β–H), 0.91 (s,
General. The NMR spectra were measured with a
Spectrometer NMR Varian Mercury 300 MHz (Oxford,
UK), operating at 300.07 and 75.4614 MHz for H and
1
13C, respectively. Typical conditions for the proton spec-
tra were as follows: pulse width 32°, acquisition time 5 s,
FT size 32 K and digital resolution 0.3 Hz per point, and
for the carbon spectra, pulse width 60°, FT size 60 K and
digital resolution 0.6 Hz per point, the number of scans
varied from 1200 to 10,000 per spectrum. The 13C and 1H
chemical shifts were measured in CDCl3 and DMSO-d6
relative to an internal standard of TMS. Infrared spectra
were recorded in the KBr pellets or film using a FT-IR Bruker
IFS 66 spectrometer (Karlsruhe, Germany). The ESI (elec-
tron spray ionisation) mass spectra were recorded on a
Waters/Micromass (Manchester, UK) zQ mass spectrom-
eter equipped with a Harvard Apparatus (Saint Laurent,
Canada), syringe pump. The sample solutions were pre-
pared in methanol at the concentration of approximately
10−5 M. The standard ESI-MS mass spectra were recorded
at the cone voltage of 90 V. PM5 semiempirical calculations
were performed using the WinMopac 2003 program. The
MALDI (matrix-assisted laser desorption/ionisation) mass
spectra were recorded on a Waters Maldi Q-Tof Premiere.
The sample solutions were prepared in methanol at the
concentration of approximately 10−5 M. The matrix was
2,5-dihydroxybenzoic acid (gentisic acid), and the standard
was β-cyclodextrin (m/z 1157.3218).
2.2. Preparation of ligands (11–15)
Procedure for compound (11): Propargyl lithocholate
(330 mg, 0.8 mmol) was dissolved in a mixture of t-butanol/
methanol (6 mL, 5:1), and 1,3-di(azidomethyl)benzene
(75 mg, 0.4 mmol) was added. Next, to the homogenous
mixture were added CuSO4·5H2O (3 mg, 3 mol%) and
sodium ascorbate (9 mg, 20 mol%) in water (0.3 mL). The
reaction mixture was heated at 60 °C for 5 h and then
extracted with chloroform, washed with brine and dried

SUPRAMOLECULAR CHEMISTRy
3
6H, CH3–19), 0.87 (d, J = 5.1 Hz, 6H, CH3–21), 0.61 (s, 6H,
CH3–18). 1H NMR (DMSO-d6): δ 8.18 (s, 2H, CH-triazole ring),
7.34–7.25 (m, 4H, Ar–H), 5.58 (s, 4H, Ph–CH2–triazole ring),
5.10 (s, 4H, O–CH2–triazole ring), 4.45 (d, J = 4.5 Hz, 2H,
3α–OH), 3.48–3.37 (m, 2H, 3β–H), 0.87 (s, 6H, CH3–19), 0.84
(d, J = 6.3 Hz, 6H, CH3–21), 0.57 (s, 6H, CH3–18). 13C NMR
(CDCl3): δ 174.11, 143.58, 135.58, 130.01, 128.33, 127.54,
123.69, 71.79, 57.38, 56.46, 55.88, 53.71, 42.69, 42.05,
40.39, 40.13, 36.42, 35.80, 35.29, 34.54, 31.06, 30.82, 30.52,
28.16, 27.16, 26.38, 24.16, 23.34, 20.78, 18.21, 11.99. 13C
NMR (DMSO-d6): δ 173.02, 172.94, 142.17, 136.48, 129.20,
127.78, 127.59, 124.80, 69.82, 56.91, 55.99, 55.43, 52.49,
42.22, 41.49, 39.93, 39.78, 39.63, 39.22, 38.94, 38.67, 36.26,
35.33, 35.12, 34.69, 34.17, 30.49, 30.41, 30.35, 27.64, 26.87,
26.12, 23.79, 23.24, 20.37, 18.01, 11.77. HRMS (MALDI)
(m/z): calcd for C62H92N6O6Cl [M + Cl]: 1051.6766; found:
1051.6735.
Compound (12). yield 58% (255 mg), m.p. 99–105 °C.
FT-IR (KBr) νmax: 3423, 2935, 2862, 1734, 1448, 1164, 754. 1H
NMR (CDCl3): δ 7.55 (s, 2H, CH-triazole ring), 7.27–7.22 (m, 4H,
Ar–H), 5.52 (s, 4H, Ph–CH2–triazole ring), 5.19 (s, 4H, O–CH2–
triazole ring), 3.95 (s, 2H, 12β–H), 3.66–3.55 (m, 2H, 3β–H),
0.91 (s, 6H, CH3–19), 0.92 (d, J = 8.1 Hz, 6H, CH3–21), 0.65 (s,
6H, CH3–18). 1H NMR (DMSO-d6): δ 8.18 (s, 2H, CH-triazole
ring), 7.43–7.40 (m, 4H, Ar–H), 5.58 (s, 4H, Ph–CH2–triazole
ring), 5.10 (s, 4H, O–CH2–triazole ring), 4.46 (d, J = 4.3 Hz, 2H,
3α–OH), 4.18 (d, J = 4.1 Hz, 2H, 12α–OH), 3.77 (d, J = 3.5 Hz,
2H, 12β–H), 3.41–3.28 (m, 2H, 3β–H), 0.88 (d, J = 6.3 Hz, 6H,
CH3–21), 0.84 (s, 6H, CH3–19), 0.55 (s, 6H, CH3–18). 13C NMR
(CDCl3): δ 174.07, 143.58, 135.59, 130.01, 128.37, 127.54,
123.69, 76.58, 73.03, 71.71, 57.41, 53.72, 48.24, 47.13, 46.45,
42.04, 36.39, 35.97, 35.22, 35.12, 34.08, 33.60, 31.09, 30.77,
30.45, 29.66, 28.65, 27.45, 27.09, 26.11, 23.62, 23.12, 17.23,
12.66. 13C NMR (DMSO-d6): δ 172.99, 142.20, 136.46, 129.21,
127.75, 127.60, 124.78, 70.94, 69.90, 56.90, 52.50, 47.40,
46.11, 45.95, 41.57, 39.78, 39.23, 38.95, 38.67, 36.26, 35.60,
35.11, 34.83, 33.77, 32.88, 30.55, 30.20, 28.54, 27.09, 26.95,
26.05, 23.44, 23.05, 16.80, 12.33. HRMS (MALDI) (m/z): calcd
for C62H92N6O8Cl [M + Cl]: 1083.6665; found: 1083.6647.
Compound (13). yield 40% (172 mg), m.p. 108–115 °C.
FT-IR (KBr) νmax: 3420, 2930, 1734, 1464, 1168, 753. 1H
NMR (CDCl3): δ 7.58 (s, 2H, CH-triazole ring), 7.27–7.20
(m, 4H, Ar–H), 5.52 (s, 4H, Ph–CH2–triazole ring), 5.19 (s,
4H, O–CH2–triazole ring), 3.93 (s, 2H, 12β–H), 3.83 (s, 2H,
7β–H), 3.51–3.20 (m, 2H, 3β–H), 0.92 (d, J = 5.7 Hz, 6H,
CH3–21), 0.87 (s, 6H, CH3–19), 0.64 (s, 6H, CH3–18). 1H NMR
(DMSO-d6): 8.18 (s, 2H, CH-triazole ring), 7.40–7.25 (m, 4H,
Ar–H), 5.58 (s, 4H, Ph–CH2–triazole ring), 5.10 (s, 4H, O–
CH2–triazole ring), 4.31 (d, J = 4.4 Hz, 2H, 3α–OH), 4.10 (d,
J = 3.5 Hz, 2H, 12α–OH), 4.00 (d, J = 3.4 Hz, 2H, 7α–OH), 3.75
(d, J = 3.17 Hz, 2H, 12β–H), 3.61 (s, 2H, 7β–H), 3.23–3.14
(m, 2H, 3β–H), 0.81 (s, 6H, CH3–19), 0.89 (d, J = 6.2 Hz, 6H,
CH3–21), 0.55 (s, 6H, CH3–18). 13C NMR (CDCl3): δ 174.22,
143.53, 135.60, 129.99, 128.38, 127.58, 123.80, 72.94, 71.84,
68.37, 57.46, 53.71, 46.75, 46.39, 41.65, 41.47, 39.47, 35.27,
34.73, 31.05, 30.77, 30.38, 28.17, 27.54, 26.37, 23.19, 22.46,
17.23, 12.41. 13C NMR (DMSO-d6): δ 173.03, 142.21, 136.45,
129.22, 127.75, 127.62, 124.77, 79.12, 70.95, 70.40, 66.21,
56.91, 52.51, 46.04, 45.72, 41.49, 41.32, 39.78, 39.22, 38.95,
38.67, 35.28, 34.92, 34.84, 34.35, 30.62, 30.55, 30.37, 28.47,
27.20, 26.17, 22.75, 22.58, 16.83, 12.23. HRMS (MALDI)
(m/z): calcd for C62H92N6O10Cl [M + Cl]: 1115.6564; found:
1115.6549.
Compound (14). yield 42% (162 mg), m.p. 145–149 °C.
FT-IR (KBr) νmax: 3430, 2932, 1744, 1451, 1227, 1163, 754.
1H NMR (CDCl3): δ 7,54 (s, 2H, CH-triazole ring), 7.33–7.20
(m, 4H, Ar–H), 5.50 (s, 4H, Ph–CH2-triazole ring), 5.19 (s,
4H, O–CH2–triazole ring), 4.88–4.69 (m, 2H, 3β–H), 3.80 (s,
4H, 3α–CH2–Br), 0.93 (s, 6H, CH3–19), 0.87 (d, J = 6.1 Hz,
6H, CH3–21), 0.62 (s, 6H, CH3–18). 13C NMR (CDCl3): δ
174.09, 166.74, 143.55, 135.59, 130.00, 129.00, 128.34,
127.55, 123.71, 57.38, 56.41, 55.92, 53.71, 42.70, 41.86,
41.22, 40.39, 40.06, 35.74, 35.28, 34.89, 34.55, 32.01,
31.90, 31.06, 30.81, 30.48, 29.67, 28.16, 26.95, 26.40, 26.36,
26.27, 24.14, 23.27, 20.81, 18.27, 12.0. ESI-MS (m/z): 1157.3
[C66H96N6O8 + CH3OH + K]+.
Compound (15). yield 39% (225 mg), 151–154 °C. FT-IR
1
(KBr) νmax: 3424, 2926, 1734, 1449, 1285, 1158, 754. H
NMR (CDCl3): δ 7,54 (s, 2H, CH-triazole ring), 7.33– 7.22
(m, 4H, Ar–H), 5.50 (s, 4H, Ph–CH2-triazole ring), 5.18 (s,
4H, O–CH2–triazole ring), 5.14 (s, 2H, 12β–H), 4.89–4.71
(m, 2H, 3β–H), 3.84 (s, 4H, 3α–CH2–Br), 0.92 (s, 6H, CH3–19),
0.78 (d, J = 6.1 Hz, 6H, CH3–21), 0.72 (s, 6H, CH3–18). 13C
NMR (CDCl3): δ 173.92, 166.70, 166.54, 143.42, 135.57,
129.99, 129.68, 128.99, 128.53, 128.34, 128.18, 127.93,
127.56, 123.75, 57.38, 54.29, 53.91, 53.70, 49.24, 49.15,
47.21, 45.11, 41.68, 41.19, 35.55, 34.70, 34.61, 34.24,
34.03, 33.98, 31.89, 31.77, 30.97, 30.55, 29.66, 27.31, 26.75,
26.35, 26.20, 25.99, 25.85, 25.49, 25.28, 23.39, 22.87, 17.40,
12.27. ESI-MS (m/z): 1135,3 [C66H96N6O10 + H]+, 1154,3
[C66H96N6O10 + H + Na]+.
2.3. Preparation of adducts of dimers (11–13)
Sample of compound (11) (10 mg, 0.0098 mmol) was
dissolved in acetonitrile. Then, phthalic acid (1.63 mg,
0.0098 mmol) was added in acetonitrile. The mixture was
evaporated to dryness.
Sample of compound (11) (10 mg, 0.0098 mmol) was
dissolved in acetonitrile. Then, terephthalic acid (1.63 mg,
0.0098 mmol) was added in acetonitrile. The mixture was
evaporated to dryness.
Sample of compound (11) (10 mg, 0.0098 mmol) was
dissolved in acetonitrile. Then, p-aminobenzoic acid

4
T. POSPIESzNy ET AL.
CH2Br
CH2N3
NaN3, acetone, H2O
CH2Br
CH2N3
(1)
(2)
O
CO2H
O
R2
R2
1) propargyl alcohol, DCC, DMAP, CH2Cl2
2) BrCH2COBr, NaH, TEBA, PhCH3
R1
R1
OR3
OH
(3) R1 = R2 = H
(6) R1 = R2 = H, R3 = H
(4) R1 = H, R2 = OH
(5) R1 = R2 = OH
(7) R1 = H, R2 = OH, R3 = H
(8) R1 = R2 = OH, R3 = H
(9) R1 = R2 = H, R3 = COCH2Br
(10) R1 = H, R2 = OH, R3 = COCH2Br
21
19
18
12
O
24
R2
7
3
O
R1
25
27
OR3
28
26
N
1,3-di(azidomethyl)benzene,
sodium ascorbate,
N
(6) or (7) or (8)
(9) or (10)
N
(2) +
29
CuSO4 x 5H2O, t-BuOH/MeOH
N
N
(5:1, 60oC)
N
OR3
R1
O
R2
O
(11) R1 = R2 = H, R3 = H
(12) R1 = H, R2 = OH, R3 = H
(13) R1 = R2 = OH, R3 = H
(14) R1 = R2 = H, R3 = COCH2Br
(15) R1 = H, R2 = OH, R3 = COCH2Br
Scheme 1. (colour online) Synthesis of 1,3-di(azidomethyl)benzene (2), propargyl esters of bile acids (6–10) and dimers of bile acids
derivatives (11–15) linked by 1,2,3-triazole ring.
(1.35 mg, 0.0098 mmol) was added in acetonitrile. The
mixture was evaporated to dryness.
(1.3 mg, 0.0095 mmol) was added in acetonitrile. The mix-
ture was evaporated to dryness.
Sample of compound (12) (10 mg, 0.0095 mmol) was
dissolved in acetonitrile. Then, phthalic acid (1.57 mg,
0.0095 mmol) was added in acetonitrile. The mixture was
evaporated to dryness.
Sample of compound (13) (10 mg, 0.0093 mmol) was
dissolved in acetonitrile. Then, phthalic acid (1.54 mg,
0.0093 mmol) was added in acetonitrile. The mixture was
evaporated to dryness.
Sample of compound (12) (10 mg, 0.0095 mmol) was
dissolved in acetonitrile. Then, terephthalic acid (1.57 mg,
0.0095 mmol) was added in acetonitrile. The mixture was
evaporated to dryness.
Sample of compound (13) (10 mg, 0.0093 mmol) was
dissolved in acetonitrile. Then, terephthalic acid (1.54 mg,
0.0093 mmol) was added in acetonitrile. The mixture was
evaporated to dryness.
Sample of compound (12) (10 mg, 0.0095 mmol) was
dissolved in acetonitrile. Then, p-aminobenzoic acid
Sample of compound (13) (10 mg, 0.0093 mmol) was
dissolved in acetonitrile. Then, p-aminobenzoic acid

SUPRAMOLECULAR CHEMISTRy
5
Table 1. 1h Nmr and 13c Nmr chemical shifts (ppm) of compounds (11–13) in cDcl3.
Compound
11
12
13
1H NMR
13C NMR
1H NMR
13C NMR
1H NMR
13C NMR
No. of atom
3
3.67–3.57
–
–
71.79
–
–
3.66–3.55
–
3.95
0.65
0.91
0.92
–
5.19
–
7.55
5.52
7.27–7.22
71.71
–
3.51–3.20
3.83
3.93
0.64
0.87
0.92
–
5.19
–
71.84
68.39
72.94
12.41
22.46
17.23
174.22
41.49
143.53
123.80
53.71
129.99
128.38
127.58
7
12
18
19
21
24
25
26
27
28
29
73.03
12.66
23.12
17.23
174.07
42.04
143.58
123.69
53.72
130.01
128.37
127.54
0.61
0.91
0.87
–
5.19
–
7.55
5.51
7.27–7.22
11.99
20.78
18.21
174.11
42.69
143.58
123.69
53.71
135.58
130.01
128.33
7.58
5.52
7.27–7.20
Table 2. 1h Nmr and 13c Nmr chemical shifts (ppm) of compounds (11–13) in DmSo-d6.
Compound
11
12
13
1H NMR
13C NMR
1H NMR
13C NMR
1H NMR
13C NMR
No. of atom
3
3.48–3.37
–
–
69.82
–
–
3.41–3.28
–
3.77
0.55
0.84
0.88
–
5.10
–
8.18
5.58
7.43–7.40
69.90
–
3.23–3.14
3.61
3.75
0.55
0.81
0.89
–
5.10
–
66.21
70.40
70.95
12.23
22.75
16.83
173.03
41.32
142.21
124.77
52.51
136.45
129.22
127.75
–
7
12
18
19
21
24
25
26
27
28
29
70.94
12.33
23.05
16.80
172.99
41.57
142.20
124.78
52.50
136.46
129.21
127.60
–
0.57
0.87
0.84
–
5.10
–
8.18
5.58
7.34–7.25
11.77
23.34
18.01
172.94
42.22
142.17
124.80
52.49
136.48
129.70
127.78
–
8.18
5.58
7.40–7.25
3OH
7OH
12OH
4.45
–
–
4.46
–
4.18
4.31
4.00
4.10
–
–
–
–
–
–
Table 3. the differences Δ (ppm) between the respective chemical shifts.
Compound
11
12
13
Δ 1H
Δ 13
C
Δ 1H
Δ 13
C
Δ 1H
Δ 13
C
No. of atom
3
0.20
–
–
0.04
0.04
0.03
–
0.09
–
1.97
–
–
0.26
–
0.18
0.10
0.07
0.04
–
0.09
–
–0.63
–0.06
–0.17
1.81
–
0.17
0.22
0.18
0.09
0.06
0.03
–
0.09
–
–0.60
–0.06
–0.09
5.63
–2.01
1.99
0.18
–0.29
0.40
1.19
0.17
1.32
–0.97
1.20
7
12
18
19
21
24
25
26
27
28
29
2.09
0.33
0.07
0.43
1.08
0.47
1.38
–1.09
1.22
–6.45
–0.84
–0.06
0.22
–2.56
0.20
1.17
0.47
1.41
–1.11
1.22
–0.90
0.31
0.55
–0.63
–0.07
–0.05
–6.46
–0.84
–0.17
Notes.
Δ1h = δ(11 in cDcl3) – δ(11 in DmSod6); Δ13c = δ(11 in cDcl3) – δ(11 in DmSod6).
Δ1h = δ(12 in cDcl3) – δ(12 in DmSod6); Δ13c = δ(12 in cDcl3) – δ(12 in DmSod6).
Δ1h = δ(13 in cDcl3) – δ(13 in DmSod6); Δ13c = δ(13 in cDcl3) – δ(13 in DmSod6).

6
T. POSPIESzNy ET AL.
(a)
Figure 1a. (Colour online) 1H NMR in 4.5–3.0 ppm region of dimers (11–13) and its adducts with phthalic acid, terephthalic and paBa
in DmSo-d6.
(1.27 mg, 0.00933 mmol)] was added in acetonitrile. The
mixture was evaporated to dryness.
acids and azide groups of 1,3,5-tris(azidomethyl)ben-
zene and a quasi-podands with 1,2,3-triazole rings (40).
Encouraged by these works, in this paper we describe
the application of the CuAAC reaction for the synthesis
of 1,2,3-triazoles containing bile acid, as well as the appli-
cation of the previously unknown dimers in the literature
to adduct formation with 1,2-benzenedicarboxylic acid
(phthalic acid), 1,4-benzenedicarboxylic acid (terephthalic
acid) and 4-aminobenzoic acid (PABA, vitamin B10).
The synthetic route to prepare 1,3-di(azidomethyl)
benzene (2), propargyl esters of bile acids (6–8) and their
bromoacetoxy derivatives (9,10) and conjugates (11–15)
is shown in Scheme 1. The structures of all synthesised
conjugates (11–15) as well as adducts of (11–13) with
2.4. Semiempirical calculations
The optimised geometries, natural bond orbital charge
distributions and the heats of formation (HOF) of the free
ligand as well as adducts were calculated by the PM5 suite
of programs (37–39). PM5 semiempirical calculations were
performed using the WinMopac 2003 program.
3. Results and discussion
In our previous work, we described intermolecular
1,3-dipolar cycloaddition of the propargyl ester of bile

SUPRAMOLECULAR CHEMISTRy
7
(b)
Figure 1b. (Continued). 1H NMR in 4.5–3.0ppm region of dimers (12) and its adducts with phthalic acid, terephthalic and PABA
in DMSO-d6.
1,2-benzenedicarboxylic acid, 1,4-benzenedicarboxylic acid
and 4-aminobenzoic acid were determined from their 1H and
13C NMR, FT-IR and MALDI-MS spectra. Moreover, PM5 calcu-
lation methods were performed for all compounds (37–39).
were synthesised by the reaction of corresponding bile
acid propargyl esters with bromoacetic acid bromide in
anhydrous toluene with sodium hydride and TEBA. This
one-pot reaction leads to bile acid derivatives with 53
and 47% yield, respectively. The azide (2) and propargyl
esters of bile acids (6–8) and its derivatives (9,10) were
used as a substrate in the ‘click’ reaction in the presence
of CuSO4·5H2O and sodium ascorbate. Application of
mixtures of solvents: t-BuOH/MeOH (5:1) gave very good
results. The mixture of products (11–15) was obtained and
separated by column chromatography. Additionally, con-
jugate (13) has been studied as a ligand in the formation
of hydrogen bonds with the 1,2-benzenedicarboxylic acid,
1,4-benzenedicarboxylic acid and 4-aminobenzoic acid.
3.1. Synthesis studies
The 1,3-di(azidomethyl)benzene (2), propargyl esters of
bile acids (6–8) and bromoacetoxy derivatives of prop-
argyl esters of bile acids (9,10) were prepared according
to the literature procedures (41–43). The bile acid esters
were obtained with high yields (95–99%). The propargyl
3α-bromoacetoxy-5β-cholan-24-oate (9) and propargyl
3α-bromoacetoxy-12α-hydroxy-5β-cholan-24-oate (10)

8
T. POSPIESzNy ET AL.
(c)
Figure 1c. (Continued). 1H NMR in 4.5–3.0ppm region of dimers (13) and its adducts with phthalic acid, terephthalic and PABA
in DMSO-d6.
range of 3.68–3.14 ppm assigned to the 3β–H protons of
the steroid skeleton and two hydrogen singlets ranging
from 0.65 to 0.55 and 0.91 to 0.81 and characteristic dou-
blets at 0.92–0.84 ppm assigned to CH3–18, CH3–19 and
CH3–21, respectively. In the 1H NMR spectrum in DMSO-d6
of (11–13), the protons of 3α–OH hydroxyl groups are
found as a doublet at 4.45, 4.46 and 4.31 ppm, respec-
tively. On the other hand, protons of 12α–OH in (12) and
(13) as well as 7α–OH in (13) are located at 4.18, 4.10 and
4.00 ppm, respectively. The 1H NMR spectra of compounds
(14) and (15) show characteristic singlets in the range of
3.84–3.80 ppm for the protons of the 3α-OCOCH2Br group.
This is consistent with our previous studies of bromo-
acetyl-substituted derivatives of bile acids (43).
3.2. NMR studies
The 1H and 13C NMR data of compounds (11–13) are shown
in Tables 1 and 2, respectively. The differences Δ (ppm)
between the respective chemical shifts observed in the
spectra of the dimers in chloroform and DMSO-d6 are
shown in Table 3.
In the 1H NMR spectrum of compounds (11–13) in both
solutions, the signals of the benzene ring protons are
found in the range of 7.43–7.20 ppm. The proton signals
of the triazole ring C(27)H arise as a singlet at about 7.55
and 8.18 ppm, assigned in CDCl3 and DMSO-d6, respec-
tively. The protons of methylene group C(25)H are located
in a very similar range at 5.19 ppm. The 1H NMR spectra of
compounds (11–13) show characteristic multiplets in the

SUPRAMOLECULAR CHEMISTRy
9
100
80
(a)
60
3420
40
1734
100
(b)
80
60
2527
2651
3425
1734
1701
40
100
(c)
2551
2666
80
60
1693
1734
3425
40
100
(d)
95
90
85
1676
3405
1734
3500
3000
2500
2000
1800
1600
1400
1200
1000
800
600
400
-1
Wavenumbers/cm
Figure 2. (colour online) the Ft-ir spectra of dimer (11) (a) and for adduct of dimer (11) with phthalic acid (b), terephthalic acid (c), and
paBa (d).
The adducts were obtained from the corresponding
dimer of bile acids (11–13) and aromatic acids (phthalic
acid, terephthalic acid and PABA). The 1H NMR spectra of
obtained adducts were performed in DMSO-d6. In Figure 1
are shown the 1H NMR spectrum of ligands 11, 12 and 13
and their adducts.
A characteristic feature of these spectra is the broad-
ening of the signals 3β-H and 12β-H and broadening
and flattening of signals 3α-OH and 12α-OH. For dimer
13, it was demonstrated that the greatest change in the
1H NMR spectrum is shown in its adduct with phthalic
acid. Signals 7α-OH and 12α-OH were substantially flat-
tened, and signal 3α-OH disappeared. This is due to the
participation of these groups in the formation of hydro-
gen bonds. The probability of hydrogen bond formation
is much higher at the ortho position. Introduction of the
bromoacetyl group in C(3)α position of the steroid skel-
eton (14) and (15) prevented the formation of adduct
with hydrogen bonds. It suggests that only hydroxyl
groups form hydrogen bonds, without the participa-
tion of nitrogen atoms of the triazole ring. On the other
hand, the protons of carboxyl groups in phthalic and
1
terephthalic acid as well as PABA in H NMR spectra are
at about 13 and 12 ppm, respectively. They create a broad
signal. However, in the spectra of the adducts, we can
see the complete flattening of the signals in these areas.

10
T. POSPIESzNy ET AL.
Table 4. heat of formation (hoF) [kcal/mol] of guest molecules and dimers as well as its adducts.
Substrates
HOF [kcal/mol]
ΔHOF [kcal/mol]
phthalic acid
terephthalic acid
paBa
–154.2706
–157.2468
–69.1173
–
–
–
–
–
–
–
–
11
–286.5609
–371.0931
–449.7501
–365.9395
–450.8937
hoF [kcal/mol]
–448.0196
–445.0589
–363.3503
–531.5170
–528.0278
–447.3165
–617.5121
–615.3107
–530.4993
12
13
14
15
Adducts
ΔhoF [kcal/mol]
–7.1881
–1.2512
–7.6721
–6.1533
0.3121
–7.1061
–13.4914
–8.3135
–11.6319
11 + phthalic acid
11 + terephthalic acid
11 + paBa
12 + phthalic acid
12 + terephthalic acid
12 + paBa
13 + phthalic acid
13 + terephthalic acid
13 + paBa
Notes.
ΔhoF = hoF(adduct 11) – [hoF(Dimer 11) + hoF(phthalic acid)].
ΔhoF = hoF(adduct 11) – [hoF(Dimer 11) + hoF(terephthalic acid)].
ΔhoF = hoF(adduct 11) – [hoF(Dimer 11) + hoF(paBa)].
ΔhoF = hoF(adduct 12) – [hoF(Dimer 12) + hoF(phthalic acid)].
ΔhoF = hoF(adduct 12) – [hoF(Dimer 12) + hoF(terephthalic acid)].
ΔhoF = hoF(adduct 12) – [hoF(Dimer 12) + hoF(paBa)].
ΔhoF = hoF(adduct 13) – [hoF(Dimer 13) + hoF(phthalic acid)].
ΔhoF = hoF(adduct 13) – [hoF(Dimer 13) + hoF(terephthalic acid)].
ΔhoF = hoF(adduct 13) – [hoF(Dimer 13) + hoF(paBa)].
13
13+Phthalic acid
13+Terephtalic acid
13+PABA
Figure 3. (colour online) molecular models of representative dimer (13) and its adducts with phthalic and terephthalic acid and paBa
calculated by pm5 method.
The visible differences in chemical shifts of the signals
in the 13C NMR spectra of dimers in chloroform and in
DMSO-d6 solutions appear for carbon atoms in steroid
skeleton: C(3), C(21), C(24). In the case of dimers (12)
and (13), differences in chemical shifts of signals C(7)
and C(12) were also seen. Smaller differences in chemi-
cal shifts of carbons were observed for C(25), C(26) and
C(27). This demonstrates the greater involvement in the
interactions of the hydroxyl groups of the steroid skel-
eton with solvent.

SUPRAMOLECULAR CHEMISTRy
11
Figure 4. (colour online) molecular models of conjugates (13) calculated by pm5 method six molecules (a) sand channel formed by
twelve molecules (b).
The shape of the spectra is a proof of the formation
of the H-bonds. The νOH frequency calculated by PM5
method in adduct of dimer (11) with phthalic acid, tere-
phthalic acid and PABA exhibits a linear relationship for
hydrogen bond length: dimer (11) with phthalic acid
O···O = 4.06; 3.64 and 3.29 Å, dimer (11) with terephthalic
acid O···O = 3.87; 3.79; 3.57 and 3.32 Å and dimer (11) with
PABA O···O = 2.96 Å, respectively.
3.3. FT-IR studies
The FT-IR spectra of dimer (11) and for adduct of dimer (11)
with phthalic acid, terephthalic, and PABA are shown in Figure
2. The intense broad absorption in the 3500–3300 cm−1
region corresponds to the overlapping νOH and νNH
stretching vibrations. In adducts, this band is broadened and
shifted to lower frequencies due to intra- and intermolecular
H-bonding of OH groups (Figure 2). The most prominent
feature of FT-IR spectra are bands in carbonyl region. The
carboxylic acids usually absorb in the region of range 1725–
1700 cm−1, while esters absorb somewhat at a higher fre-
quencyrangeof1750–1735cm−1.ThepresenceofH-bonding
in the molecule causes the additional shift of these bands:
1734 cm−1 for dimer (11) (Figure 2(a)), 1734 and 1701 cm−1 for
its adducts with phthalic acid, 1734 and 1693 cm−1 with tere-
phthalic acid and 1734 and 1676 cm−1 with PABA (Figure 2
(b)–(d)).
3.4. Semiempirical studies
PM5 semiempirical calculations were performed using
the WinMopac 2003 program. The final HOF [kcal/mol] for
phthalic acid, terephthalic acid, PABA and dimers (11–15)
as well as adducts of dimers (11), (12) and (13) are pre-
sented in Table 4. Representative compounds (13) and its
adducts are shown in Figure 3.

12
T. POSPIESzNy ET AL.
In the case of HOF of dimers (11–13), a clear correlation
References
is shown such that with the increase in the number of free
hydroxyl groups in steroid skeletons, the value of HOF
decreases. It can be also caused by difficulty to form intra-
molecular hydrogen bonds. In turn, the dimers (14) and
(15) with a lower HOF are deoxycholic acid derivatives.
This fact can be additionally explained by the greater
stability of bromoester groups in isolated molecule. On
the other hand, the HOF of all adducts is lower than the
HOF of corresponding dimers. This is due to the forma-
tion of intermolecular hydrogen bonds, which was con-
(1) Hofmann, A.F.; Hagey, L.R.; Krasowski, M.D. J. Lipid Res.
2010, 51, 226–246.
(2) Chiang, J.y.L. J. Lipid Res. 2009, 50, 1955–1966.
(3) Russell, D.W. Annu. Rev. Biochem. 2003, 72, 137–174.
(4) Dewick, P.M. In Medicinal natural products, 3rd ed. Wiley:
Chichester. 2009; 275–277.
(5) Gao, H.; Dias, J.R. Org. Prep. Proced. Int. 1999, 31, 145–166.
(6) yuexian, L.; Dias, J.R. Chem. Rev. 1997, 97, 283–304.
(7) Davis, A.P. Chem. Soc. Rev. 1993, 22, 243–253.
(8) Wallimann, P.; Marti, T.; Fürer, A.; Diederich, F. Chem. Rev.
1997, 97, 1567–1608.
(9) Tamminen, J.; Kolehmainen, E. Molecules 2001, 6, 21–46.
(10) Gao, H.; Dias, J.R. J. Prakt. Chem. 1997, 339, 187–190.
(11) Li, y.X.; Dias, J.R. Org. Prep. Proced. Int. 1996, 28, 203–209.
(12) Hsieh, H.P.; Muller, J.G.; Burrows, C.J. J. Am. Chem. Soc.
1994, 116, 12077–12078.
(13) Guthrie, J.P.; Cullimore, P.A.; McDonald, R.S.; O’Leary, S.
Can. J. Chem. 1982, 60, 747–764.
(14) Paryzek, z.; Joachimiak, R.; Piasecka, M.; Pospieszny, T.
Tetrahedron Lett. 2012, 53, 6212–6215.
(15) Willemen, H.M.;Vermonden, T.; Marcelis, A.T.M.; Sudhölter,
E.J.R. Eur. J. Org. Chem. 2001, 12, 2329–2335.
(16) Willemen, H.M.;Vermonden, T.; Marcelis, A.T.M.; Sudhölter,
E.J.R. Langmuir 2002, 18, 7102–7106.
(17) Valkonen, A.; Lahtinen, M.; Virtanen, E.; Kaikkonen, S.;
Kolehmainen, E. Biosens. Bioelectron. 2004, 20, 1233–1241.
(18) Salunke, D.B.; Hazra, B.G.; Pore, V.S. Curr. Med. Chem. 2006,
13, 813–847.
1
firmed by H NMR spectrum analysis and FT-IR. Besides
hydrogen bonding, these adducts may be stabilised by
electrostatic interactions that arise from the number of
hydroxyl groups in the bile acid molecule which is related
with a corresponding geometry of the molecule.
The spatial arrangement and interaction of the conju-
gate 13 are shown in Figure 4. The final heat of formation
is −2737.5566 kcal/mol (Figure 4(a)), and the distances
between the benzene rings in vertical and between the
triazole rings and atom C(3) steroid skeleton in horizontal
are 19.1 and 8.9 Å, respectively. In contrast, the heat of for-
mation of supramolecular compound is –5481.8837 kcal/
mol (Figure 4(b)) . The molecules are arranged to form spe-
cific kind of channel, through which ions or neutral mole-
cules can be transferred. Compensation charges occur only
through intermolecular electrostatic interaction. This is a
very good confirmation of the conclusion that interactions
reduce HOF.
(19) Kolb, H.C.; Finn, M.G.; Sharpless, K.B. Ang. Chem. Int. Ed.
2001, 40, 2004–2021.
(20) Kolb, H.C.; Finn, M.G.; Sharpless, K.B. Ang. Chem. 2001,
113, 2056–2075.
(21) Presolski, P.I.; Hong, V.P.; Finn, M.G. Curr. Protoc. Chem. Biol.
2011, 3, 153–162.
(22) Narayan, S.; Muldoon, J.; Finn, M.G.; Fokin, V.V.; Kolb, H.C.;
Sharpless, K.B. Angew. Chem. Int. Ed. 2005, 44, 3275–3279.
(23) Palaniraja, J.; Roopan, S.M. Chem. Sci. Rev. Lett. 2014, 10,
93–100.
(24) Boren, Brant C.; Narayan, S.; Rasmussen, L.; zhang, L.;
zhao, H.; Lin, z.; Jia, G.; Fokin, V. J. Am. Chem. Soc. 2008,
130, 8923–8930.
(25) Latyshev, G.V.; Baranov, M.S.; Kazantsev, A.V.; Averin, A.D.;
Lukashev, N.V.; Beletskaya, I.P. Synthesis 2009, 15, 2605–
2615.
(26) Pore, V.S.; Aher, N.G.; Kumar, M.; Shukla, P.K. Tetrahedron
2006, 62, 11178–11186.
(27) zhang, J.; Luo, J.; zhu, X.X.; Junk, M.J.N.; Hinderberger, D.
Langmuir 2010, 26, 2958–2962.
(28) Kumar, A.; Chhatra, R.K.; Pandey, P.S. Org. Lett. 2010, 12,
24–27.
(29) Aher, N.G.; Pore, V.S.; Mishra, N.N.; Kumar, A.; Shukla, P.K.;
Sharma, A.; Bhat, M.K. Bioorg. Med. Chem. Lett. 2009, 19,
759–763.
(30) Vatmurge,N.S.;Hazra,B.G.;Pore,V.S.;Shirazi,F.;Deshpande,
M.V.; Kadreppa, S.; Chattopadhyay, S.; Gonnade, R.G. Org.
Biomol. Chem. 2008, 6, 3823–3830.
4. Conclusion
In summary, three new dimers of bile acids linked with
1,2,3-triazole ring (11–13) and two dimers of bromo-
acetyl-substituted derivatives of bile acids (14), (15) were
prepared from propargyl esters of bile acids and 1,3-di(azi-
domethyl)benzene in t-butanol/methanol mixture in the
presence of sodium ascorbate and CuSO4·5H2O at 60 °C.
These dimers linked with 1,2,3-triazole ring were charac-
terised by spectroscopic (FT-IR, NMR) and molecular struc-
ture (PM5) methods. It has been shown that the hydroxyl
group participates in the formation of hydrogen bonds
with phthalic acid, terephthalic acid and PABA and forms
adducts.
Supplemental material
Supplemental data for this paper can be accessed online
here: http://dx.doi.org/10.1080/10610278.2016.1175568
(31) Sokolova, N.V.; Latyshev, G.V.; Lukashev, N.V.; Nenajdenko,
V.G. Org. Biomol. Chem. 2011, 9, 4921–4926.
(32) Chhatra, R.K.; Kumar, A.; Pandey, P.S. J. Org. Chem. 2011,
76, 9086–9089.
Disclosure statement
No potential conflict of interest was reported by the authors.

SUPRAMOLECULAR CHEMISTRy
13
(33) Aher, N.G.; Pore, V.S. Synlett 2005, 14, 2155–2158.
(34) Tornøe, ChW; Christensen, C.; Meldal, M. J. Org. Chem.
2002, 67, 3057–3064.
(35) zhang, L.; Chen, X.; Xue, P.; Sun, H.H.y.; Williams, I.D.;
Sharpless, K.B.; Fokin, V.V.; Jia, G. J. Am. Chem. Soc. 2005,
127, 15998–15999.
(36) Latyshev, G.V.; Baranov, M.S.; Kazantsev, A.V.; Averin, A.D.;
Lukashev, N.V.; Beletskaya, I.P. Synthesis 2009, 15, 2605–2615.
(37) CAChe 5.04 UserGuide, Fujitsu, 2003
(39) Stewart, J.J.P. J. Comp. Chem. 1989, 10, 209–220.
(40) Pospieszny,T.; Koenig, H.; Kowalczyk, I.; Brycki, B. Molecules
2014, 19, 2557–2570.
(41) Brycki, B.; Koenig, H.; Kowalczyk, I.; Pospieszny,T. Molecules
2013, 18, 14961–14976.
(42) Aher, N.G.; Pore, V.S.; Patil, S.P. Tetrahedron 2007, 63,
12927–12934.
(43) Pospieszny, T.; Koenig, H.; Kowalczyk, I.; Brycki, B. Acta
Chim. Slov. 2015, 62, 15–27.
(38) Stewart, J.J.P. J. Comp. Chem. 1991, 12, 320–341.