Design, synthesis, and cytotoxicity evaluation of threonine-based galactoceramide with aromatic groups and various fatty-acyl side chains

Article abstract of DOI:10.1007/s00044-017-2049-9

Abstract: In galactoceramides, presence of fatty-acyl group on amide moiety or phytosphingosine group is some of the important features that influence the cytotoxicity. Continuous efforts are in progress to modify the fatty-acid moiety and phytosphingosine group present on the galactoceramides to enhance the cytotoxic potential of these compounds. Hence, in the present study, threonine-based β-galactoceramide and its derivatives were prepared by modifying the fatty-acyl group on amide moiety with different fatty-acyl moieties and aromatic acids employing trichloroacetimidate methodology. The structurally related threonine-based ceramide part was synthesized in multi-step process using different reagents. The ceramide part was glycosylated with galactose using trichloroacetimidate as donor. Further, all the synthesized compounds were evaluated for in vitro cytotoxicity against three cancer cell lines and one normal cell line and all the compounds exhibited good to moderate cytotoxicity against all the tested cancer cell lines. In aromatic derivatives, the compound 8i exhibited promising activity against MCF7, A549 and HeLa cancer cell lines with IC₅₀ values of 14.08, 14.78, and 16.70 μM, respectively. In fatty-acid derivatives, two compounds exhibited promising activity, i.e., compound 8m against HeLa with IC₅₀ value 16.34 μM and compound 8n against MCF7 with IC₅₀ value 18.05 μM. Based on structure–activity relationship, aromatic acid derivatives exhibited potential activity as compared to fatty-acid derivatives. Further, the influence of some of the key factors such as spacer chain length between aromatic residue and amide functional group, methoxy substituents on aryl group, terminal unsaturation of fatty acid and branching chain effect on the cytotoxicity are discussed.

Full text of DOI:10.1007/s00044-017-2049-9

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res
DOI 10.1007/s00044-017-2049-9
ORIGINAL RESEARCH
Design, synthesis, and cytotoxicity evaluation of threonine-based
galactoceramide with aromatic groups and various fatty-acyl side
chains
1
,2 ●
3 ●
2,3 ●
Srikanth Vudhgiri
R. B. N. Prasad
Sunitha Rani Routhu C. Ganesh Kumar
1
,2 ●
1,2
Ram Chandra Reddy Jala
Received: 23 March 2017 / Accepted: 22 August 2017
Springer Science+Business Media, LLC 2017
©
Abstract In galactoceramides, presence of fatty-acyl group
on amide moiety or phytosphingosine group is some of the
important features that influence the cytotoxicity. Con-
tinuous efforts are in progress to modify the fatty-acid
moiety and phytosphingosine group present on the galac-
toceramides to enhance the cytotoxic potential of these
compounds. Hence, in the present study, threonine-based β-
galactoceramide and its derivatives were prepared by
modifying the fatty-acyl group on amide moiety with dif-
ferent fatty-acyl moieties and aromatic acids employing
trichloroacetimidate methodology. The structurally related
threonine-based ceramide part was synthesized in multi-step
process using different reagents. The ceramide part was
glycosylated with galactose using trichloroacetimidate as
donor. Further, all the synthesized compounds were eval-
uated for in vitro cytotoxicity against three cancer cell lines
and one normal cell line and all the compounds exhibited
good to moderate cytotoxicity against all the tested cancer
cell lines. In aromatic derivatives, the compound 8i exhib-
ited promising activity against MCF7, A549 and HeLa
cancer cell lines with IC50 values of 14.08, 14.78, and
16.70 µM, respectively. In fatty-acid derivatives, two com-
pounds exhibited promising activity, i.e., compound 8m
against HeLa with IC50 value 16.34 µM and compound 8n
against MCF7 with IC50 value 18.05 µM. Based on
structure–activity relationship, aromatic acid derivatives
exhibited potential activity as compared to fatty-acid deri-
vatives. Further, the influence of some of the key factors
such as spacer chain length between aromatic residue and
amide functional group, methoxy substituents on aryl
group, terminal unsaturation of fatty acid and branching
chain effect on the cytotoxicity are discussed.
Graphical abstract
●
●
●
Keywords Threonine Galactoceramide Aromatic acids
●
Fatty acids Cytotoxicity
Electronic supplementary material The online version of this article
https://doi.org/10.1007/s00044-017-2049-9) contains supplementary
material, which is available to authorized users.
Introduction
*
Ram Chandra Reddy Jala
jrcreddy10@gmail.com
ramchandra@iict.res.in
Galactoceramide is a bioactive glycolipid and it has been
shown to possess antitumor activity (Natori et al.
(1993, 1994); Motoki et al. 1995). In galactoceramides, the
glycosidic bond exists between sugar moiety and the cer-
amide part, which consists of a fatty acid and sphingoid
chain. In higher organisms, these glycosidic bond has a
typically β-configuration. Natori and co-workers from Kirin
Brewery, Japan originally isolated these glycolipids from an
1
Centre for Lipid Research, CSIR-Indian Institute of Chemical
Technology, Tarnaka, Hyderabad 500007, India
2
3
Academy of Scientific and Innovative Research, New Delhi, India
Medicinal Chemistry and Pharmacology Division, CSIR-Indian
Institute of Chemical Technology, Tarnaka, Hyderabad 500007,
India

Med Chem Res
extract of marine sponge, Agelas mauritianus (Natori et al.
1993, 1994); Motoki et al. 1995). Since last two decades,
and isolated β-galactosylceramide was reported earlier
(Wallner et al. 2005). These glycolipids exhibited different
biological activities such as cytotoxicity (Motoki et al.
1995), anti-HIV-1 (Faroux-Corlay et al. 2000), β-
glucocerebrosidase activity in keratinocytes (Fukunaga
et al. 2003), and also exhibited opposing effects on the
production of chemokines and proinflammatory cytokines
(Roeske-Nielsen et al. 2004).
Apart from above studies, galactoceramide derivatives
with modified phytosphingosine or fatty-acid moiety exhib-
ited different immunoactivities (Smyth and Godfrey 2000;
Chang et al. 2007; Hung et al. 2007; Huang et al. 2011;
Wallner et al. 2005; Fan et al. 2005) and also in view of the
potential antitumor activity of oleic acid derivatives (Garcia-
Alvarez et al. 2011; Carrillo et al. 2012) in the present study,
synthesis and cytotoxic evaluation of structurally related
galactoceramide derivatives of threonine-based β-galactosyl
ceramides was carried out. In this study, the fatty-acyl group
on amide moiety was replaced with different aromatic acids
and various unusual, branched, saturated and unsaturated
fatty-acyl moieties. Further, oleyl amine moiety was attached
to threonine acid group by mimicking phytosphingosine long
chain in ceramide (Fig. 1).
(
galactoceramide and its synthetic analogues have gained a
renewed attention in the scientific community due to their
high-potential antitumor activity (Natori et al. 1994; Motoki
et al. 1995; Nakagawa et al. 1998) in the view of its ver-
satile utility as iNKT activators (Nakagawa et al. 1998;
Hayakawa et al. 2004; Kawano et al. 1998) and adjuvants
for the treatment of many diseases like malaria (Gonzalez-
Aseguinolaza et al. (2000, 2002)) HIV (Huang et al. 2008),
tumor immunotherapy (Giaccone et al. 2002), tuberculosis
(
Sada-Ovalle et al. 2010) and also it inhibited allergic air-
way inflammation (Matsuda et al. 2005). Moreover, the
phase I clinical trials proved that galactoceramide was
ineffective in the treatment of solid tumors (Giaccone et al.
2
002). Therefore, new galactoceramide analogues are
required for the treatment.
The SAR study on α-GalCer showed that the modifica-
tion on the sphingosine OH group leads to a change in the
binding effect without losing total activity of α-GalCer
(
Zhang et al. 2011) and modification of fatty-acyl group on
amide moiety or phytosphingosine group gave better results
in enhancing the antitumor promoting activity (Smyth and
Godfrey 2000; Yogesh Kumar et al. 2016; Chang et al.
2
007). In view of this, Fujio and co-workers reported the
design and synthesis of various fatty-acyl chain analogues
with replacement of fatty-acyl group on amide moiety with
different aromatic acids and evaluated the NKT cell acti-
vation by measuring cytokine release profiles. These results
demonstrated that the introduction of an aromatic group to
the fatty-acyl chain greatly influences the cytokine release
and also long chain analogues were more potent than
shorter chain aromatic groups (Fujio et al. 2006). In addi-
tion, Wu and co-workers reported the presence of an
additional hydrogen bond between the phenyl/aryl ring of
the fatty-acyl chain and aromatic amino-acid residues pre-
Experimental procedures
Materials and methods
All the chemicals were of analytical grade obtained from
different commercial sources and used without any further
purification. All the dry reactions were carried out under
nitrogen atmosphere using anhydrous freshly distilled sol-
vents and sieved through molecular sieves (4 Å) in flame
dried glassware using standard gas-light syringes and septa.
Reactions were monitored using micro thin layer chromato-
graph (TLC) plates (coated with TLC grade silica gel,
ʹ
sent on the wall of the A pocket in the CD1d hydrophobic
groove (Wu et al. 2006).
In addition, there exist a few other reports where the
phytosphingosine group was modified with structurally
related amino acids such as serine and evaluated for their
different immunoactivities (Hung et al. 2007; Huang et al.
2
011; Wallner et al. 2005; Fan et al. 2005). In this regard, it
is noteworthy to mention that threonine is structurally
related to phytosphingosine group. Moreover, threonine-
based vaccines are signaling molecules in the human CD1d
cytoplasmic tail (Liu et al. 2010). α-N-Acetyl galactosa-
mine-O-serine/threonine-based conjugate vaccine works
against most of cancers, especially most effectively against
prostate cancer (Slovin et al. 2003). Furthermore, glyco-
sphingolipids like β-galactosylceramide (1) are available in
nature with numerous applications (Wallner et al. 2005).
Synthesis and evaluation of different activities of synthetic
Fig. 1 Structures of target molecule

Med Chem Res
obtained from Merck) and the spots were detected by iodine
vapors. Column chromatography was performed using silica
gel (100–200 mesh) procured from Qualigens (India) by
= 8.85 Hz, 1H, NH), 6.55 (d, J = 15.71 Hz, 1H,=CH), 4.77
(dd, J = 2.44, 8.85 Hz, 1H, CH–NH), 4.42 (m, 1H,
CH–OH), 3.78 (s, 3H, OCH ), 1.26 (d, J = 6.41 Hz, 3H,
3
1
13
eluting freshly distilled solvents. All the H-NMR (nuclear
CH3); C-NMR (CDCl , 75 MHz): 171.7 (O–C=O), 166.7
3
13
magnetic resonance) and C-NMR spectra were recorded on
(HN––C=O), 142.1 (HC=CH), 134.5 (Ar–C), 129.9 (Ar–
CH), 128.8 (Ar–CH), 127.9 (Ar–CH), 119.9 (HC=CH),
1
a Bruker UXNMR (Operating for H-NMR at 300 MHz, 400
1
3
MHz, 500 MHz, and for C-NMR at 75 MHz, 100 MHz,
25 MHz) spectrometer, using TMS (δ = 0) as an internal
standard for chemical shifts (δ) in CDCl , CD OD and
68.1 (HC-OH), 57.6 (HC–NH), 52.6 (O–CH ), 20 (HOHC–
3
1
CH ); IR (KBr): 3479, 3305, 2964, 1721, 1658, 1543, 1278,
3
1080, 977, 732, 545; ESI–MS: m/z at 286.06 [M + Na].
3
3
DMSO-d at 25 °C. Mass spectra were recorded with HRMS
6
and ESI–MS (electron spray ionization technique). Infrared
Methyl 4—nitro cinnamoyl-L-threoninate (2b)
(
IR) spectra were recorded with a Perkin-Elmer Fourier-
1
transform infrared spectroscopy (FT-IR) spectrum BX. The
melting points were determined on a Barnstead electro ther-
mal 9200 instrument.
Hexane: ethyl acetate (50:50, v/v), yield 78%. H-NMR
(CDCl , 500 MHz): 8.18–8.24 (m, 2H, Ar–H), 7.61–7.71
(m, 3H, Ar–H,=CH), 6.66–6.72 (m, 2H, NH,=CH), 4.76
3
(
m, 1H, CH–NH), 4.44 (m, 1H, CH–OH), 3.81 (s, 3H,
1
3 3 3
3
Preparation of L-threonine methyl ester hydrochloride (1)
OCH ), 1.29 (d, J = 6.25 Hz, 3H, CH ); C-NMR (CDCl ,
1
00 MHz): 171.5 (O–C=O), 165.4 (HN–C=O), 148.1 (Ar–
C–NO ), 140.7 (HC=CH), 139.1 (Ar–C), 128.4 (Ar–CH),
124.1 (Ar–CH), 124 (HC=CH), 67.9 (HC–OH), 57.6
(HC–NH), 52.7 (O–CH ), 20 (HOHC–CH ); IR (KBr):
3478, 3305, 2964, 1716, 1658, 1622, 1543, 1345, 1278,
1086, 977, 732, 545; ESI–MS: m/z at 331.04 [M + Na].
L-Threonine was dissolved in methanalic HCl solution (2 M)
and refluxed the reaction mixture for 1 h. Then the organic
solvent was evaporated using rotary evaporator and again
same methanalic HCl solution was added to the reaction
mixture and refluxed for 1 h. After the reaction time, the
organic solvent was evaporated under reduced pressure to
2
3
3
+
give white solid compound. ESI–MS: m/z at 134.2 [M +H].
Methyl (2-(1H-indol-3-yl) acetyl)-L-threoninate (2c)
1
Hexane: ethyl acetate (60:40, v/v), yield 82%. H-NMR
General procedure for synthesis of aromatic acid/fatty
acid-based methyl–L-threoninate (2a–2s)
(
CDCl + DMSO-d 500 MHz): 10.51 (br s, 1H, Ar–NH),
.57 (d, J = 7.93 Hz, 1H, Ar–H), 7.35 (d, J = 8.08 Hz, 1H,
3 6,
7
Ar–H), 7.18 (s, 1H, Ar–H), 7.09 (t, J = 7.09 Hz, 1H, Ar–H),
A mixture of 10.25 mmol of L-threonine methyl ester
7
4
.02 (t, J = 7.47 Hz, 1H, Ar–H), 4.44 (m, 1H, CH–NH),
.20 (m, 1H, CH–OH), 3.72 (s, 2H, CH ), 3.64 (s, 3H,
hydrochloride (1) and Et N (2 mL) was dissolved in ice-
cold anhydrous dichloromethane (40 mL) and kept in ice for
3
2
1
3
OCH ), 1.06 (d, J = 6.41 Hz, 3H, CH ); C-NMR (CDCl3
2
0 min with stirring. This was followed by the addition of
3
3
DMSO-d , 100 MHz): 171.8 (O–C=O), 171 (HN–C=O),
36.1 (Ar–C–NH), 126.9 (Ar–C–CH), 123.7 (Ar–CH),
21.1 (Ar–CH), 118.5 (Ar–CH), 118.3 (Ar–CH), 111.2
acid (12.3 mmol), 1-ethyl-3-(3-dimethylaminopropyl) car-
bodiimide hydrochloride (EDC.HCl, 12.3 mmol) and
hydroxy benzotriazole (HOBt, 15.38 mmol) successively at
+
6
1
1
(Ar–CH), 107.9 (Ar–C), 66.5 (HC–OH), 57.6 (HC–NH),
0
°C. The mixture was left at room temperature for 12 h
5
1.7 (O–CH ), 32.7 (H C–C=O), 19.9 (HOHC–CH ); IR
under magnetic stirring. The reaction was monitored using
micro TLC (hexane: ethyl acetate, 1:1, v/v). At the end of
the reaction, the reaction mixture was dissolved in chloro-
form (75 mL) and then it was washed by 5% NaHCO3
solution, saturated NaCl solution successively. The
chloroform layer was dried with anhydrous Na SO and the
filtrate was dried under vacuum. The crude mixture was
purified by silica-gel chromatography by using hexane,
ethyl acetate solvent mixture to get the title compound with
3
2
3
(KBr): 3409, 3345, 2967, 1738, 1640, 1519, 1457, 1298,
1130, 1015, 747; ESI–MS: m/z at 313.1 [M + Na].
Methyl (3-(1H-indol-3-yl) propanoyl)-L-threoninate (2d)
2
4
1
Hexane: ethyl acetate (60:40, v/v), yield 84%. H-NMR
(CDCl , 500 MHz): 8.18 (br s, 1H, Ar–NH), 7.59 (m, 1H,
3
Ar–H), 7.33 (m, 1H, Ar–H), 7.17 (m, 1H, Ar–H), 7.11 (m,
H, Ar–H), 7.01 (m, 1H, Ar–H), 6.29 (br s, 1H, NH), 4.55
m, 1H, CH-–NH), 4.21 (m, 1H, CH–OH), 3.70 (s, 3H,
OCH ), 3.12 (m, 2H, CH ), 2.66 (m, 2H, CH ), 1.03 (s, 3H,
1
(
7
8–84% yield.
Methyl cinnamoyl-L-threoninate (2a)
Hexane: ethyl acetate (60:40, v/v), yield 81%. H-NMR
3
2
2
1
3
CH3); C-NMR (CDCl , 100 MHz): 173.6 (O–C=O),
3
1
171.6 (HN–C=O), 136.2 (Ar–C–NH), 127 (Ar–C–CH),
121.8 (Ar–CH), 119.1 (Ar–CH), 118.5 (Ar–CH), 114.4
(Ar–CH), 112.2 (Ar–C), 67.8 (HC–OH), 57.3 (HC–NH),
(
(
CDCl , 500 MHz): 7.65 (d, J = 15.71 Hz, 1H,=CH), 7.49
m, 2H, Ar–H), 7.33 (t, J = 3.66 Hz, 3H, Ar–H), 6.75 (d, J
3

Med Chem Res
5
1
1
5
2.4 (O–CH ), 36.8 (H C–C=O), 21.1 (H C–H C–C=O),
Methyl (2-(4-methoxyphenyl) acetyl)-L-threoninate (2h)
3
2
2
2
9.6 (HOHC–CH ); IR (KBr): 3412, 3338, 2967, 1742,
3
1
658, 1519, 1462, 1298, 1217, 1130, 1015, 1087, 842, 747,
02; ESI–MS: m/z at 327.04 [M + Na].
Hexane: ethyl acetate (60:40, v/v), yield 80%. H-NMR
(CDCl 400 MHz): 7.21 (d, J = 8.55 Hz, 2H, Ar–H), 6.89
3
,
(
4
d, J = 8.55 Hz, 2H, Ar–H), 6.21 (d, J = 8.06 Hz, 1H, NH),
.58 (dd, J = 2.44, 8.80 Hz, 1H, CH–NH), 4.31 (m, 1H,
CH–OH), 3.80 (s, 3H, Ar–OCH ), 3.73 (s, 3H, OCH ), 3.58
Methyl (1H-indazole-3-carbonyl)-L-threoninate (2e)
3
3
(
s, 2H, CH ), 1.91 (br s, 1H, OH), 1.13 (d, J = 6.48 Hz, 3H,
2
1
Hexane: ethyl acetate (50:50, v/v), yield 81%. H-NMR
13
CH3); C-NMR (CDCl , 125 MHz): 172.1 (O–C=O),
1
C–CH ), 126.4 (Ar–CH), 114.3 (Ar–CH), 67.8 (HC–OH),
5
(
3
6
3
(
CDCl + DMSO-d6, 400 MHz): 8.02 (br s, 1H, Ar–NH),
3
71.3 (HN–C=O), 158.8 (Ar–C–OCH ), 130.3 (Ar–
3
7
.78 (m, 1H, Ar–H), 7.28 (m, 1H, Ar–H), 7.08 (m, 1H,
Ar–H), 6.95 (m, 1H, Ar–H), 4.67 (m, 1H, CH–NH), 4.53
m, 1H, CH–OH), 3.48 (s, 3H, OCH ), 1.03 (m, 3H, CH );
C-NMR (CDCl + DMSO-d 125 MHz): 171.3 (O–
C=O), 163.1 (HN–C = O), 141.2 (Ar–C–NH), 137.5
O=C–(Ar)C=NH), 126.3 (Ar–CH), 122.1 (Ar–CH), 121.5
Ar–CH), 121.4 (Ar-CH), 110.4 (Ar–C), 67 (HC–OH), 57.2
HC–NH), 52 (O–CH ), 20.1 (HOHC–CH ); IR (KBr):
2
7.2 (HC–NH), 55.2 (Ar–C–O–CH ), 52.5 (O–CH ), 42.5
3 3
(
3
3
Ar–CH –C=O), 19.8 (HOHC–CH ); IR (KBr): 3478,
2
3
1
3
3
6,
338, 2956, 1728, 1649, 1513, 1287, 1248, 1083, 1018,
98; ESI–MS: m/z at 304.1 [M + Na].
(
(
Methyl (4-(4-methoxyphenyl) butanoyl)-L-threoninate (2i)
(
3
3
3
1
532, 3358, 3028, 2969, 1742, 1670, 1519, 1458, 1298,
218, 1130, 1016, 1087, 842, 747; ESI–MS: m/z at 300.07
1
Hexane: ethyl acetate (60:40, v/v), yield 82%. H-NMR
(
(
CDCl 500 MHz): 7.09 (d, J = 8.54 Hz, 2H, Ar–H), 6.82
d, J = 8.69 Hz, 2H, Ar–H), 6.41 (br s, 1H, NH), 4.61 (dd,
3,
[
M + Na].
J = 2.28, 8.85 Hz, 1H, CH–NH), 4.34 (m, 1H, CH–OH),
3
.78 (s, 3H, Ar–OCH ), 3.75 (s, 3H, OCH ), 2.60 (t, J =
3 3
Methyl (1H-indole-2-carbonyl)-L-threoninate (2f)
7.47 Hz, 2H, CH ), 2.27 (t, J = 7.32 Hz, 2H, CH ), 1.95 (m,
2
2
1
3
1
2H, CH ), 1.20 (d, J = 6.41 Hz, 3H, CH ); C-NMR
2
3
Hexane: ethyl acetate (60:40, v/v), yield 80%. H-NMR
(
(
(
CDCl + DMSO-d , 75 MHz): 173.2 (O–C=O), 171.2
3
HN–C=O), 157.4 (Ar–C–OCH ), 133.3 (Ar–C–CH ), 129
Ar–CH), 113.4 (Ar–CH), 67 (HC–OH), 57.4 (HC–NH),
6
(
DMSO-d 400 MHz): 10.83 (s, 1H, Ar–NH), 7.78 (d, J =
6
,
3
2
7
.33 Hz, 1H, Ar–H), 7.54 (m, 1H, Ar–H), 7.38 (m, 1H,
Ar–H), 7.15 (m, 1H, Ar–H), 7.09 (s, 1H, Ar–H), 7.00 (m,
54.8 (Ar–C–O–CH3), 51.8 (O–CH3), 35.1 (H C–
2
1
3
H, NH), 4.68 (m, 1H, CH–NH), 4.30 (m, 1H, CH–OH),
1
3
CH –C=O), 33.8 (Ar–C–CH ), 27.1 (CH ), 19.8 (HOHC–
CH ); IR (KBr): 3458, 3334, 2956, 1711, 1638, 1513, 1287,
2 2 2
.67 (s, 3H, OCH ), 1.18 (d, J = 6.48 Hz, 3H, CH ); C-
3
3
3
NMR (CDCl + DMSO-d 125 MHz): 171 (O–C=O),
3
6,
1249, 1053, 1020, 698; ESI–MS: m/z at 332.1 [M + Na].
1
(
1
(
61.7 (HN–C=O), 136.4 (Ar–C–NH), 130.4 (O=C–C
NH)=CH), 126.8 (Ar–C), 123.6 (Ar–CH), 121.3 (Ar–CH),
19.7 (Ar–CH), 111.9 (Ar–CH), 103.7 (Ar–CH), 67.1
HC–OH), 57.8 (HC–NH), 51.8 (O–CH ), 19.9 (HOHC–
Methyl hexanoyl-L-threoninate (2j)
3
1
Hexane: ethyl acetate (70:30, v/v), yield 89%. H-NMR
CDCl3, 500 MHz): 6.46(br s, 1H, NH), 4.58 (m, 1H,
CH–NH), 4.34 (m, 1H, CH–OH), 3.75 (s, 3H, OCH ), 2.28
CH ); IR (KBr): 3586, 3362, 2968, 1738, 1645, 1519, 1457,
3
(
1
298, 1217, 1130, 1015, 1068, 842, 747, 502; ESI–MS: m/z
3
at 299.1 [M + Na].
(m, 2H, O=C–CH ), 1.65 (m, 2H, CH ), 1.32 (m, 4H,
2 2
1
3
CH ), 1.20 (s, 3H, CHOH–CH ), 0.89 (m, 3H, CH ); C-
2
3
3
Methyl (2-phenylacetyl)-L-threoninate (2g)
NMR (CDCl3, 100 MHz): 174.1 (O–C=O), 171.5 (HN–
C=O), 67.6 (HC–OH), 57.2 (HC–NH), 52.3 (O–CH ), 36.3
3
1
Hexane: ethyl acetate (65:35, v/v), yield 82%. H-NMR
CDCl 400 MHz): 7.28 (m, 5H, Ar–H), 6.68 (d, J = 8.80
(O=C–CH ), 31.2 (CH ), 25.2 (CH ), 22.2 (CH ), 19.8
2
2
2
2
(
(HOHC–CH ), 13.8 (CH ); IR (KBr): 3353, 2956, 2866,
3
,
3 3
Hz, 1H, NH), 4.52 (dd, J = 2.69, 8.92 Hz, 1H, CH–NH),
.26 (m, 1H, CH–OH), 3.67 (s, 3H, OCH ), 3.58 (s, 2H,
1723, 1645, 1532, 1287, 1020, 696; ESI–MS: m/z at 254.1
[M + Na].
4
3
1
3
CH ), 1.08 (d, J = 6.35 Hz, 3H, CH ); C-NMR (CDCl3,
2
3
1
25 MHz): 172 (O–C=O), 171.2 (HN–C=O), 134.5 (Ar–
Methyl octanoyl-L-threoninate (2k)
C–CH ), 129 (Ar–CH), 128.5 (Ar–CH), 126.9 (Ar–CH),
2
1
6
7.3 (HC–OH), 57.4 (HC–NH), 52.2 (O–CH ), 42.9 (Ar–
Hexane: ethyl acetate (70:30, v/v), yield 88%. H-NMR
3
CH –C=O), 19.6 (HOHC–CH ); IR (KBr): 3476, 3327,
(CDCl3, 400 MHz): 6.44 (d, J = 8.68 Hz, 1H, NH), 4.61
(dd, J = 2.56, 8.92 Hz, 1H, CH–NH), 4.32–4.37 (m, 1H,
2
3
2
955, 1711, 1647, 1513, 1287, 1249, 1083, 1020, 698;
ESI–MS: m/z at 274.1 [M + Na].
CH–OH), 3.76 (s, 3H, OCH ), 2.28 (t, J = 7.45 Hz, 2H, O
3

Med Chem Res
=
C–CH ), 1.62–1.69 (m, 2H, CH ), 1.28–1.32 (m, 8H,
22.5 (CH ), 19.8 (HOHC–CH ), 14 (CH ); IR (KBr): 3494,
2 3 3
2
2
CH ), 1.21 (d, 3H, CHOH-CH ), 0.88 (t, J = 6.72, 3H,
3309, 2918, 2850, 1721, 1646, 1545, 1281, 1019, 716;
ESI–MS: m/z at 324.2 [M + Na].
2
3
1
3
CH3); C-NMR (CDCl3, 125 MHz): 174.2 (O–C=O),
71.5 (HN–C=O), 67.6 (HC–OH), 57.2 (HC–NH), 52.3
O–CH ), 36.3 (O=C–CH ), 31.6 (O=C–CH –CH ), 29.1
1
(
(
3
2
2
2
Methyl dodecanoyl-L-threoninate (2o)
CH ), 28.8 (CH ), 25.6 (CH ), 22.4 (CH ), 19.7 (HOHC–
2
2
2
2
CH ), 13.9 (CH ); IR (KBr): 3355, 2968, 2866, 1733, 1645,
3
3
1
Hexane: ethyl acetate (70:30, v/v), yield 80%. H-NMR
(
1
528, 1287, 1020, 696; ESI–MS: m/z at 282.2 [M + Na].
CDCl3, 400 MHz): 6.21 (br s, 1H, NH), 4.61 (m, 1H,
CH–NH), 4.35 (m, 1H, CH–OH), 3.77 (s, 3H, OCH ), 2.28
3
Methyl (2-propylpentanoyl)-L-threoninate (2l)
(
t, J = 7.7 Hz, 2H, O=C–CH ), 1.66 (m, 2H, CH ), 1.25 (m,
2 2
1
16H, CH ), 1.22 (d, J = 6.35 Hz, 3H, CHOH–CH ), 0.88 (t,
2 3
1
Hexane: ethyl acetate (70:30, v/v), yield 82%. H-NMR
CDCl3, 500 MHz): 6.43 (br s, 1H, NH), 4.63 (m, 1H,
CH–NH), 4.37 (m, 1H, CH–OH), 3.75 (s, 3H, OCH3),
3
J = 6.11 Hz, 3H, CH3); C-NMR (CDCl 125 MHz): 174
3,
(
(
(
(
O–C=O), 171.6 (HN–C=O), 67.9 (HC–OH), 57
HC–NH), 52.4 (O–CH3), 36.5 (O=C–CH2), 31.8
O=C–CH -CH ), 29.6 (CH ), 29.4 (CH ), 29.3 (CH ),
2
.17–2.22 (m, 1H, CH), 1.62 (m, 2H, CH ), 1.31–1.40 (m,
H, CH ), 1.21 (m, 3H, CHOH–CH ), 0.90–0.92 (m, 6H,
CH3); C-NMR (CDCl3, 75 MHz): 177 (O–C=O), 171.6
HN–C=O), 67.6 (HC–OH), 57 (HC–NH), 52.4 (O–CH3),
7.5 (O=C–CH), 35.3 (O=C–CH–CH ), 35.1 (O=C–CH–
2
2
2
2
2
2
6
2
3
3
1
29.2 (CH ), 29 (CH ), 25.6 (CH ), 24.7 (CH ), 22.6 (CH ),
2 2 2 2 2
1
2
3
9.8 (HOHC–CH ), 14 (CH ); IR (KBr): 3482, 3323, 2918,
3 3
856, 1745, 1658, 1545, 1278, 1019, 718; ESI–MS: m/z at
38.1 [M + Na].
(
4
2
CH ), 20.7 (CH ), 20.6 (CH ), 19.9 (HOHC–CH ), 14.1
2
2
2
3
(
CH ); IR (KBr): 3362, 2958, 2866, 1728, 1647, 1532,
3
1
287, 1018, 696; ESI–MS: m/z at 282.1 [M + Na].
Methyl tetradecanoyl-L-threoninate (2p)
Hexane: ethyl acetate (70:30, v/v), yield 85%. H-NMR
Methyl undec-10-enoyl-L-threoninate (2m)
1
(
(
CDCl3, 500 MHz): 6.26 (d, J = 8.69 Hz, 1H, NH), 4.63
dd, J = 2.59, 8.85 Hz, 1H, CH–NH), 4.33–4.37 (m, 1H,
1
Hexane: ethyl acetate (70:30, v/v), yield 84%. H-NMR
CDCl3, 400 MHz): 6.45 (d, J = 8.80 Hz, 1H, NH),
5
(
CH–OH), 3.77 (s, 3H, OCH ), 2.28 (t, J = 7.47 Hz, 2H,
O=C–CH ), 1.61–1.68 (m, 2H, CH ), 1.25 (m, 20 H, CH ),
1
3
1
3
.75–5.85 (m, 1H,=CH), 4.96–5.01 (m, 1H,=CH2),
.91–4.94 (m, 1H,=CH ), 4.59 (dd, J = 2.44, 8.92 Hz, 1H,
CH–NH), 4.31–4.36 (m, 1H, CH–OH), 3.75 (s, 3H, OCH3),
.96 (s, 1H, OH), 2.28 (t, J = 7.45 Hz, 2H, O=C–CH2),
.0–2.06 (m, 2H,=CH–CH ), 1.61–1.68 (m, 2H, CH ),
.28–1.38 (m, 10H, CH ), 1.20 (d, J = 6.48 Hz, 3H,
CHOH–CH3); C-NMR (CDCl3, 125 MHz): 174.04 (O–
C=O), 171.5 (HN–C=O), 138.9 (H C–HC=CH), 114.0
H C–HC=CH), 67.6 (HC–OH), 57.1 (HC–NH), 52.3 (O–
2
2
2
4
2
.22 (d, J = 6.4 Hz, 3H, CHOH–CH ), 0.88 (t, J = 6.86 Hz,
3
13
H, CH3); C-NMR (CDCl 100 MHz): 173.9 (O–C=O),
3,
2
2
1
71.6 (HN–C=O), 67.8 (HC–OH), 57 (HC–NH), 52.4 (O–
2
2
CH ), 36.5 (O=C–CH ), 31.8 (O=C–CH –CH ), 29.6
3
2
2
2
2
(CH ), 29.4 (CH ), 29.3 (CH ), 29.2 (CH ), 25.6 (CH ),
2 2 2 2 2
1
3
2
3
2.6 (CH ), 19.8 (HOHC–CH ), 14 (CH ); IR (KBr): 3494,
2 3 3
309, 2918, 2850, 1721, 1646, 1545, 1281, 1019, 716;
2
(
2
ESI–MS: m/z at 366.2 [M + Na].
CH ), 36.3 (O=C–CH ), 33.6 (H C–HC=CH), 29.2 (CH ),
3
2
2
2
2
9.1 (CH ), 28.9 (CH ), 28.7 (CH ), 25.5 (CH ), 19.8
2 2 2 2
(
HOHC–CH ); IR (KBr): 3495, 3313, 2918, 2850, 1720,
Methyl hexadecanoyl-L-threoninate (2q)
3
1
Na].
649, 1545, 1284, 1020, 721; ESI–MS: m/z at 322.3 [M +
1
Hexane: ethyl acetate (70:30, v/v), yield 86%. H-NMR
CDCl3, 500 MHz): 6.21 (d, J = 8.54 Hz, 1H, NH), 4.62
(
Methyl undecanoyl-L-threoninate (2n)
(dd, J = 2.44, 8.85 Hz, 1H, CH–NH), 4.33–4.37 (m, 1H,
CH–OH), 3.77 (s, 3H, OCH ), 2.28 (t, J = 7.47 Hz, 2H,
3
1
Hexane: ethyl acetate (70:30, v/v), yield 81%. H-NMR
CDCl 500 MHz): 6.48 (br s, 1H, NH), 4.59–4.61 (m, 1H,
O=C–CH ), 1.63–1.68 (m, 2H, CH ), 1.25 (m, 24H, CH ),
2
2
2
(
1.21 (d, J = 6.4 Hz, 3H, CHOH–CH ), 0.88 (t, J = 6.86 Hz,
3
,
3
1
3
CH–NH), 4.32–4.36 (m, 1H, CH–OH), 3.76 (s, 3H, OCH3),
3H, CH3); C-NMR (CDCl 100 MHz): 173.8 (O–C=O),
3,
2
1
0
.28 (t, J = 7.32 Hz, 2H, O=C–CH ), 1.65 (m, 2H, CH ),
171.6 (HN–C=O), 67.9 (HC–OH), 57 (HC–NH), 52.5 (O–
CH ), 36.5 (O=C–CH ), 31.8 (O=C–CH –CH ), 29.6
2
2
.25 (m, 14H, CH ), 1.21 (d, J = 6.4 Hz, 3H, CHOH–CH ),
2
3
3
2
2
2
1
3
.87 (t, J = 6.86 Hz, 3H, CH3); C-NMR (CDCl3, 100
(CH ), 29.4 (CH ), 29.3 (CH ), 29.2 (CH ), 25.6 (CH ),
2 2 2 2 2
MHz): 174 (O–C=O), 171.5 (HN–C=O), 67.7 (HC–OH),
7.1 (HC–NH), 52.4 (O–CH ), 36.4 (O=C–CH ), 31.8
22.6 (CH ), 19.9 (HOHC–CH ), 14.1 (CH ); IR (KBr):
2 3 3
3486, 3316, 2918, 2850, 1728, 1642, 1545, 1281, 1014,
5
3
2
(
O=C–CH –CH ), 29.5 (CH ), 29.2 (CH ), 25.6 (CH ),
716; ESI–MS: m/z at 394.1 [M + Na].
2
2
2
2
2

Med Chem Res
Methyl octadecanoyl-L-threoninate (2r)
Hexane: ethyl acetate (70:30, v/v), yield 82%. H-NMR
(m, 3H, Ar–H), 7.21 (m, 2H, Ar–H), 6.55 (d, J = 15.71 Hz,
1
H,=CH), 5.92 (br s, 1H, NH), 4.71 (m, 1H, CH–NH), 4.47
1
13
(m, 1H, CH–OH), 1.18 (d, J = 5.95 Hz, 3H, CH3); C-
(
(
CDCl3, 500 MHz): 7.00 (d, J = 8.85 Hz, 1H, NH), 4.52
dd, J = 2.74, 9.0 Hz, 1H, CH–NH), 4.26–4.30 (m, 1H,
NMR (CDCl , 75 MHz): 173.7 (O–C=O), 167.6 (HN–
C=O), 142.2 (HC=CH), 134.2 (Ar–C), 129.8 (Ar–CH),
128.6 (Ar–CH), 127.9 (Ar–CH), 119.6 (HC=CH), 67.9
3
CH–OH), 3.73 (s, 3H, OCH ), 2.26 (t, J = 7.62 Hz, 2H,
3
O=C–CH ), 1.61–1.67 (m, 2H, CH ), 1.25 (m, 28H, CH ),
(HC–OH), 57.9 (HC–NH), 19.3 (HOHC–CH ); IR (KBr):
2
2
2
3
1
.18 (d, J = 6.41 Hz, 3H, CHOH–CH ), 0.87 (t, J = 6.56
3418, 2924, 2853, 1727, 1661, 1519, 1343, 1216, 760;
ESI–MS: m/z at 248.1 [M–H].
3
1
3
Hz, 3H, CH3); C-NMR (CDCl3, 125 MHz): 173.8 (O–
C=O), 171.6 (HN–C=O), 67.9 (HC–OH), 57 (HC–NH),
5
2
2.5 (O–CH ), 36.5 (O=C–CH ), 31.8 (O=C–CH –CH ),
4-Nitro cinnamoyl-L-threonine (3b)
3
2
2
2
9.6 (CH ), 29.4 (CH ), 29.3 (CH ), 29.2 (CH ), 25.6
2
2
2
2
1
(
CH ), 22.6 (CH ), 19.8 (HOHC–CH ), 14.0 (CH ); IR
Chloroform: methanol (95:5 v/v), yield 94%. H-NMR
2
2
3
3
(
1
KBr): 3478, 3323, 2926, 2836, 1736, 1646, 1547, 1281,
023, 716; ESI–MS: m/z at 422.01 [M + Na].
(CDCl + DMSO-d 400 MHz): 8.23(m, 2H, Ar–H), 7.69
3
6,
(m, 3H, Ar–H,=CH), 7.63 (m, 1H,=CH), 6.87 (br s, 1H,
NH), 4.68 (dd, J = 2.44, 8.80 Hz, 1H, CH–NH), 4.43 (m,
1
3
Methyl oleoyl-L-threoninate (2s)
1H, CH–OH), 1.26 (d, J = 6.35 Hz, 3H, CH3); C-NMR
CDCl + DMSO-d 75 MHz): 172 (O–C=O), 164.8 (HN–
(
3
6,
1
Hexane: ethyl acetate (70:30, v/v), yield 80%. H-NMR
CDCl3, 500 MHz): 6.32 (d, J = 8.39 Hz, 1H, NH),
C=O), 147.3 (Ar–C–NO ), 141.2 (HC=CH), 136.8 (Ar–C),
2
(
128.1 (Ar–CH), 125.8 (Ar–CH), 123.6 (HC=CH), 66.7
5
1
.31–5.37 (m, 2H, HC=CH), 4.62 (dd, J = 2.44, 8.85 Hz,
H, CH–NH), 4.32–4.37 (m, 1H, CH–OH), 3.76 (s, 3H,
(HC–OH), 57.7 (HC–NH), 20.1 (HOHC–CH ); IR (KBr):
3426, 2928, 2858, 1736, 1642, 1526, 1343, 1228, 760;
3
OCH ), 2.28 (t, J = 7.47 Hz, 2H, O=C–CH ), 1.99–2.02
ESI–MS: m/z at 293.2 [M–H].
3
2
(
m, 4H, H C–CH=), 1.66 (m, 2H, CH ), 1.26–1.31 (m,
2
2
2
0H, CH ), 1.22 (d, J = 6.56 Hz, 3H, CHOH–CH ), 0.88 (t,
(2-(1H-Indol-3-yl) acetyl)-L-threonine (3c)
2
3
1
3
J = 6.86 Hz, 3H, CH3); C-NMR (CDCl3, 100 MHz):
1
1
1
73.9 (O–C=O), 171.6 (HN–C=O), 129.9 (HC=CH),
29.6 (HC=CH), 67.8 (HC–OH), 57.7 (HC–NH), 52.4 (O–
Chloroform: methanol (95:5 v/v), yield 92%. H-NMR
(CDCl + DMSO-d 400 MHz): 10.1 (br s, 1H, Ar–NH),
3
6,
CH ), 36.4 (O=C–CH ), 31.8 (H C–HC=CH), 29.7 (CH ),
7.58 (d, J = 7.45 Hz, 1H, Ar–H), 7.37 (m, 1H, Ar–H), 7.19
(s, 1H, Ar–H), 7.12 (m, 1H, Ar–H), 7.04 (m, 1H, Ar–H),
4.46 (dd, J = 2.56, 8.80 Hz, 1H, CH–NH), 4.25 (m, 1H,
3
2
2
2
2
9.6 (CH ), 29.4 (CH ), 29.2 (CH ), 29.1 (CH ), 27.1
2 2 2 2
(
(
CH ), 25.6 (CH ), 22.6 (CH ), 19.8 (HOHC–CH ), 14
2 2 2 3
CH ); IR (KBr): 3491, 3311, 2920, 2850, 1720, 1647,
CH–OH), 3.75 (s, 2H, CH ), 1.08 (d, J = 6.35 Hz, 3H,
3
2
1
3
1
546, 1281, 1021, 726; ESI–MS: m/z at 420.2 [M + Na].
CH3); C-NMR (CDCl + DMSO-d 75 MHz): 171.3 (O–
3 6,
C=O), 171 (HN–C=O), 135.1 (Ar–C–NH), 126 (Ar–
C–CH), 122.9 (Ar–CH), 120.1 (Ar–CH), 117.6 (Ar–CH),
General procedure for ester hydrolysis (3a–3s)
117.3 (Ar–CH), 110.3 (Ar–CH), 106.9 (Ar–C), 65.6
Methyl ester (1 mol) was dissolved in tetrahydrofuran,
water mixture (7:3) and then lithium hydroxide hydrate (3
mol) was added and the reaction mixture magnetically
stirred at room temperature for 16 h. After completion of the
reaction, mixture was concentrated under reduced pressure
till white precipitate obtained, which was neutralized,
extracted successively with 2 M HCl and ethyl acetate. The
organic layer was dried over anhydrous sodium sulphate
and concentrated to yield a white solid. The crude solid was
purified by silica gel column chromatography using
chloroform, methanol solvent mixture to obtain 88–95%
yield.
(HC–OH), 56.5 (HC–NH), 31.7 (H C–C=O), 19 (HOHC–
2
CH ); IR (KBr): 3424, 3312, 2931, 1742, 1646, 1534, 1498,
3
1377, 1214, 1107, 1005, 717, 549; ESI–MS: m/z at 275.01
[M–H].
(3-(1H-Indol-3-yl) propanoyl)-L-threonine (3d)
1
Chloroform: methanol (95:5 v/v), yield 95%. H-NMR
(CDCl + DMSO-d 400 MHz): 9.87 (br s, 1H, Ar–NH),
3
6,
7.55 (m, 1H, Ar–H), 7.35 (d, J = 8.19 Hz, 1H, Ar–H), 7.10
(t, J = 7.58 Hz, 1H, Ar–H), 7.05 (m, 1H, Ar–H), 7.01 (m,
1H, Ar–H), 4.48 (m, 1H, CH–NH), 4.27 (m, 1H, CH–OH),
3
.09 (t, J = 7.58 Hz, 2H, CH ), 2.66 (t, J = 7.58 Hz, 2H,
2
1
2 3 3
3
Cinnamoyl-L-threonine (3a)
CH ), 1.11 (d, J = 6.35 Hz, 3H, CH ); C-NMR (CDCl +
DMSO-d 100 MHz): 172.9 (O–C=O), 172.4 (HN–C=O),
136 (Ar–C–NH), 126.7 (Ar–C–CH), 121.6 (Ar–CH), 120.8
6
,
1
Chloroform: methanol (95:5 v/v), yield 95%. H-NMR
(
CDCl 400 MHz): 7.57 (d, J = 15.71 Hz, 1H,=CH), 7.37
3,
(Ar–CH), 118.1 (Ar–CH), 113.7 (Ar–CH), 110.9 (Ar–C),

Med Chem Res
6
7 (HC–OH), 57.2 (HC–NH), 36.5 (H C–C=O), 20.7
Ar–H), 7.08 (br s, 1H, NH), 6.84 (d, J = 8.39 Hz, 2H,
Ar–H), 4.46 (dd, J = 1.98, 8.85 Hz, 1H, CH–NH), 4.29 (m,
1H, CH–OH), 3.77 (s, 3H, Ar–OCH ), 3.55 (s, 2H, CH ),
2
(
H C–H C–C=O), 19.6 (HOHC–CH ); IR (KBr): 3456,
2 2 3
3
1
328, 2986, 1758, 1636, 1534, 1498, 1376, 1214, 1126,
018, 717, 549; ESI–MS: m/z at 289.1 [M–H].
3
1
2
3
1.12 (d, J = 4.27 Hz, 3H, CH3); C-NMR (CDCl +
3
DMSO-d6, 75 MHz): 172.1 (O–C=O), 171.1 (HN–C=O),
157.8 (Ar–C–OCH ), 129.8 (Ar–C–CH ), 126.9 (Ar–CH),
(
1H-Indazole-3-carbonyl)-L-threonine (3e)
3
2
1
13.4 (Ar–CH), 66.7 (HC–OH), 57.2 (HC–NH), 54.6
1
Chloroform: methanol (95:5 v/v), yield 96%. H-NMR
CDCl + DMSO-d6, 500 MHz): 8.26 (d, J = 8.24 Hz, 1H,
(Ar–C–O–CH ), 41.7 (Ar–CH –C=O), 19.8 (HOHC–
CH ); IR (KBr): 3336, 2958, 1768, 1636, 1513, 1236, 1178,
3
2
(
3
3
Ar–NH), 7.99 (d, J = 9.15 Hz, 1H, Ar–H), 7.53 (d, J =
.54 Hz, 1H, Ar–H), 7.33 (t, J = 7.62 Hz, 1H, Ar–H), 7.20
t, J = 7.47 Hz, 1H, Ar–H), 4.79 (d, J = 9.00 Hz, 1H,
CH–NH), 4.51 (m, 1H, CH–OH), 1.29 (d, J = 6.41 Hz, 3H,
1048, 673; ESI–MS: m/z at 266.1 [M–H].
8
(
(4-(4-Methoxyphenyl) butanoyl)-L-threonine (3i)
1
3
1
CH3); C-NMR (CDCl + DMSO-d 75 MHz): 172.6 (O–
Chloroform: methanol (95:5 v/v), yield 96%. H-NMR
3
6,
C=O), 162.9 (HN–C=O), 141 (Ar–C–NH), 137.5 (O=C–
Ar)C=NH), 126.1 (Ar–CH), 121.9 (Ar–CH), 121.4 (Ar–
CH), 110.1 (Ar–C), 67.2 (HC–OH), 56.8 (HC–NH), 19.8
HOHC–CH ); IR (KBr): 3482, 3312, 2931, 1742, 1646,
(CDCl + DMSO-d 500 MHz): 7.05 (d, J = 8.39 Hz, 2H,
3
6,
(
Ar–H), 6.90 (br s, 1H, NH), 6.79 (d, J = 8.39 Hz, 2H,
Ar–H), 4.49 (m, 1H, CH–NH), 4.37 (m, 1H, CH–OH), 3.74
(s, 3H, Ar–OCH ), 2.54 (t, J = 7.32 Hz, 2H, CH ), 2.26 (m,
(
3
3
2
1
3
1
534, 1498, 1377, 1214, 1107, 1005, 717, 549; ESI–MS: m/
2H, CH ), 1.88 (m, 2H, CH ), 1.16 (br s, 3H, CH ); C-
2 2 3
z at 263.2 [M–H].
NMR (CDCl + DMSO-d 75 MHz): 172.7 (O–C=O),
3
6,
1
72.3 (HN–C=O), 157 (Ar–C–OCH ), 133.1 (Ar–C–CH ),
3 2
(
1H-Indole-2-carbonyl)-L-threonine (3f)
128.7 (Ar–CH), 113 (Ar–CH), 66.6 (HC–OH), 56.9
HC–NH), 54.5 (Ar–C–O–CH ), 34.9 (H C–CH –C=O),
(
3
2
2
1
Chloroform: methanol (95:5 v/v), yield 97%. H-NMR
33.5 (Ar–C–CH ), 26.8 (CH ), 19.5 (HOHC–CH ); IR
2
2
3
(
CDCl + DMSO-d 500 MHz): 10.92 (br s, 1H, Ar–NH),
(KBr): 3329, 2932, 1728, 1646, 1513, 1245, 1178, 1034,
3
6,
7
.78 (m, 1H, Ar–H), 7.63 (m, 1H, Ar–H), 7.49 (m, 1H,
673; ESI–MS: m/z at 294.4 [M–H].
Ar–H), 7.22 (m, 2H, Ar–H), 7.11 (m, 1H, Ar–H), 4.73 (m,
1
3
H, CH–NH), 4.42 (m, 1H, CH–OH), 1.26 (d, J = 1.25 Hz,
Hexanoyl-L-threonine (3j)
1
3
H, CH3); C-NMR (CDCl + DMSO-d 75 MHz): 171.5
3
6,
1
(O–C=O), 160.9 (HN–C=O), 135.7 (Ar–C–NH), 129.6
(O=C–C(NH)=CH), 126(Ar–C), 122.8 (Ar–CH), 120.5
(Ar–CH), 118.9 (Ar–CH), 111.2 (Ar–CH), 103 (Ar–CH),
Chloroform: methanol (95:5 v/v), yield 95%. H-NMR
(CDCl3, 500 MHz): 7.48 (br s, 1H, COOH), 7.03 (br s,
1H, NH), 4.51 (m, 1H, CH–NH), 4.40 (m, 1H, CH–OH),
2.29 (t, J = 7.62 Hz, 2H, O=C–CH ), 1.62 (m, 2H, CH ),
6
6.1 (HC–OH), 56.9 (HC–NH), 19.2 (HOHC–CH ); IR
3
2
2
(
1
KBr): 3424, 3348, 2982, 1758, 1638, 1534, 1498, 1358,
214, 1107, 1022, 717, 549; ESI–MS: m/z at 261.3 [M–H].
1.31 (m, 4H, CH ), 1.19 (d, J = 6.41 Hz, 3H, CHOH–CH ),
2
3
1
3
0.88 (t, J = 5.95 Hz, 3H, CH3); C-NMR (CDCl3, 100
MHz): 175.3 (O–C=O), 174.1 (HN–C=O), 67.6 (HC–OH),
57.6 (HC–NH), 36.1 (O=C–CH ), 31.3 (CH ), 25.4 (CH ),
(
2-Phenylacetyl)-L-threonine (3g)
2
2
2
2
2.2 (CH ), 19.4 (HOHC–CH ), 13.8 (CH ); IR (KBr):
2 3 3
1
Chloroform: methanol (95:5 v/v), yield 96%. H-NMR
CDCl + DMSO-d6, 500 MHz): 7.27 (m, 5H, Ar–H),
3321, 2927, 2857, 1729, 1643, 1539, 1221, 1113, 758;
ESI–MS: m/z at 216.02 [M–H].
(
3
7
.13 (s, 1H, NH), 4.47 (dd, J = 2.59, 8.85 Hz, 1H,
CH–NH), 4.30 (m, 1H, CH–OH), 3.62 (s, 2H, CH ), 1.12
Octanoyl-L-threonine (3k)
2
1
3
(
d, J = 5.03 Hz, 3H, CH3); C-NMR (CDCl + DMSO-d
3 6,
1
1
00 MHz): 172.2 (O–C=O), 170.9 (HN–C=O), 134.5 (Ar–
Chloroform: methanol (92:5 v/v), yield 94%. H-NMR
C–CH ), 128.8 (Ar–CH), 128.1 (Ar–CH), 126.3 (Ar–CH),
(CDCl , 500 MHz): 7.05 (br s, 1H, NH), 4.41–4.51 (m,
2
3
6
6.9 (HC–OH), 57.3 (HC–NH), 42.7 (Ar–CH –C=O), 19.7
2H, CH–NH, CH–OH), 2.29 (m, 2H, O=C–CH ), 1.63 (m,
2
2
(
1
HOHC–CH ); IR (KBr): 3329, 2932, 1728, 1646, 1513,
245, 1178, 1034, 673; ESI–MS: m/z at 236.02 [M–H].
2H, CH ), 1.21–1.29 (m, 11H, CHOH–CH , CH ), 0.87 (t,
3
2
3
2
1
3
J = 6.56 Hz, 3H, CH3); C-NMR (CDCl3, 100 MHz):
75.2 (O–C=O), 174.3 (HN–C=O), 67.5 (HC–OH), 57.7
(HC–NH), 36.2 (O=C–CH ), 31.6((O=C–CH –CH ), 29.2
1
(
2-(4-Methoxyphenyl) acetyl)-L-threonine (3h)
2
2
2
(
CH ), 28.9 (CH ), 25.7 (CH ), 22.5 (CH ), 19.3 (HOHC–
2 2 2 2
1
Chloroform: methanol (95:5 v/v), yield 95%. H-NMR
CDCl + DMSO-d6, 500 MHz): 7.23 (d, J = 8.08 Hz, 2H,
CH ), 13.9 (CH ); IR (KBr): 3328, 2938, 2857, 1736, 1628,
3 3
1539, 1248, 1113, 758; ESI–MS: m/z at 244.1 [M–H].
(
3

Med Chem Res
(
2-Propylpentanoyl)-L-threonine (3l)
175.3 (O–C=O), 174.1 (HN–C=O), 67.6 (HC–OH), 57.6
(
HC–NH), 36.2 (O=C–CH ), 31.8 (O=C–CH –CH ), 29.6
2 2 2
1
Chloroform: methanol (92:8 v/v), yield 92%. H-NMR
CDCl3, 500 MHz): 6.43 (br s, 1H, NH), 4.63 (m, 1H,
CH–NH), 4.37 (m, 1H, CH–OH), 3.045 (s, 1H, OH),
(CH ), 29.5 (CH ), 29.4 (CH ), 29.3 (CH ), 25.7 (CH ),
2 2 2 2 2
(
22.6 (CH ), 19.3 (HOHC–CH ), 14 (CH ); IR (KBr): 3538,
2 3 3
3315, 2919, 2849, 1711, 1649, 1543, 1281, 1209, 860, 673;
2
.17–2.22 (m, 1H, CH), 1.62 (m, 2H, CH ), 1.31–1.40 (m,
ESI–MS: m/z at 300.2 [M–H].
2
6
H, CH ), 1.21 (m, 3H, CHOH–CH ), 0.90–0.92 (m, 6H,
2
3
3
1
CH3); C-NMR (CDCl3, 75 MHz): 177 (O–C=O), 171.6
HN–C=O), 67.6 (HC–OH), 57 (HC–NH), 47.5 (O=C–
CH), 35.3 (O=C–CH–CH ), 35.1 (O=C–CH–CH ), 20.7
(
Tetradecanoyl-L-threonine (3p)
2
2
1
(
CH ), 20.6 (CH ), 19.9 (HOHC–CH ), 14.1 (CH ); IR
Chloroform: methanol (92:8 v/v), yield 96%. H-NMR
2
2
3
3
(
7
KBr): 3321, 2923, 2832, 1729, 1623, 1539, 1221, 1113,
58; ESI–MS: m/z at 244.2 [M–H].
(CDCl , 500 MHz): 7.01 (br s, 1H, NH), 4.4–4.5 (m, 2H,
3
CH–NH, CH–OH), 2.29 (m, 2H, O=C–CH ), 1.62 (m, 2H,
2
CH ), 1.25 (m, 20H, CH ), 1.19 (m, 3H, CHOH–CH ), 0.87
2
2
3
1
3
Undec-10-enoyl-L-threonine (3m)
(t, J = 6.86 Hz, 3H, CH3); C-NMR (CDCl , 100 MHz):
3
1
75.2 (O–C=O), 174.3 (HN–C=O), 67.5 (HC–OH), 57.7
1
Chloroform: methanol (92:8 v/v), yield 95%. H-NMR
CDCl3, 400 MHz): 6.45 (d, J = 8.80 Hz, 1H, NH),
.75–5.85 (m, 1H,=CH), 4.91–5.01 (m, 2H,=CH ), 4.59
(HC–NH), 36.3 (O=C–CH ), 31.9 (O=C–CH –CH ), 29.7
2
2
2
(
5
(CH ), 29.6 (CH ), 29.4 (CH ), 25.8 (CH ), 22.6 (CH ),
2 2 2 2 2
19.3 (HOHC–CH ), 14 (CH ); IR (KBr): 3536, 3328, 2927,
3 3
2
(
dd, J = 2.44, 8.92 Hz, 1H, CH–NH), 4.31–4.36 (m, 1H,
2857, 1728, 1649, 1523, 1281, 1209, 860, 673; ESI–MS: m/
z at 328.1 [M–H].
CH–OH), 2.28 (t, J = 7.45 Hz, 2H, O=C–CH ), 2.0–2.06
2
(
m, 2H,=CH–CH ), 1.61–1.68 (m, 2H, CH ), 1.28–1.38
2 2
(
m, 10H, CH ), 1.20 (d, J = 6.48 Hz, 3H, CHOH–CH );
C-NMR (CDCl3, 125 MHz): 174.04 (O–C=O), 171.5
2
3
1
3
Hexadecanoyl-L-threonine (3q)
(
6
HN–C=O), 138.9 (H C–HC=CH), 114.0 (H C–HC=CH),
2 2
1
7.6 (HC–OH), 57.1 (HC–NH), 36.3 (O=C–CH ), 33.6
Chloroform: methanol (92:8 v/v), yield 95%. H-NMR
2
(
H C–HC=CH), 29.2 (CH ), 29.1 (CH ), 28.9 (CH ), 28.7
(CDCl + DMSO-d , 500 MHz): 7.02 (br s, 1H, NH),
2
2
2
2
3
6
(
2
CH ), 25.5 (CH ), 19.8 (HOHC–CH ); IR (KBr): 3345,
923, 2875, 1736, 1656, 1539, 1221, 1113, 758; ESI–MS:
4.46 (m, 1H, CH–NH), 4.29 (m, 1H, CH–OH), 2.26 (t, J =
7.78 Hz, 2H, O=C–CH ), 1.63 (m, 2H, CH ), 1.25 (s, 24H,
2
2
3
2
2
m/z at 284.1 [M–H].
CH ), 1.18 (d, J = 6.4 Hz, 3H, CHOH–CH ), 0.88 (t, J =
2 3
1
3
6
.25 Hz, 3H, CH3); C-NMR (CDCl + DMSO-d , 125
3
6
Undecanoyl-L-threonine (3n)
MHz): 173.2 (O–C=O), 172.3 (HN–C=O), 66.8 (HC–OH),
7.2 (HC–NH), 35.8 (O=C–CH ), 31.3 (O=C–CH –CH ),
29.1 (CH ), 29 (CH ), 28.9 (CH ), 28.8 (CH ), 25.3 (CH ),
2 2 2 2 2
5
2
2
2
1
Chloroform: methanol (92:8 v/v), yield 96%. H-NMR
CDCl , 500 MHz): 7.04 (br s, 1H, NH), 4.4–4.5 (m, 2H,
(
22.1 (CH ), 19.9 (HOHC–CH ), 13.7 (CH ); IR (KBr):
2 3 3
3
CH–NH, CH–OH), 2.29 (m, 2H, O=C–CH ), 1.62 (m, 2H,
3538, 3328, 2927, 2848, 1718, 1642, 1543, 1281, 1222,
2
CH ), 1.19–1.25 (m, 17H, CH , CHOH–CH ), 0.87 (t, J =
860, 673; ESI–MS: m/z at 356.02 [M–H].
2
2
3
1
3
6
.71 Hz, 3H, CH3); C-NMR (CDCl3, 100 MHz): 175.2
(
(
O–C=O), 174.3 (HN–C=O), 67.5 (HC–OH), 57.7
HC–NH), 36.4 (O=C–CH ), 31.8 (O=C–CH –CH ), 29.6
Octadecanoyl-L-threonine (3r)
2
2
2
(
1
1
CH ), 29.4 (CH ), 29.3 (CH ), 25.7 (CH ), 22.6 (CH ),
2 2 2 2 2
1
9.4 (HOHC–CH ), 14 (CH ); IR (KBr): 3321, 2927, 2857,
Chloroform: methanol (92:8 v/v), yield 96%. H-NMR
3
3
736, 1643, 1528, 1221, 1126, 758; ESI–MS: m/z at 286.3
(CDCl + DMSO-d , 500 MHz): 7.31 (t, J = 9.31 Hz, 1H,
3
6
[
M–H].
NH), 4.36–4.40 (m, 1H, CH–NH), 4.25 (m, 1H, CH–OH),
2
.24 (m, 2H, O=C–CH ), 1.60 (m, 2H, CH ), 1.25–1.27
2
2
Dodecanoyl-L-threonine (3o)
(m, 28H, CH ), 1.13–1.16 (m, 3H, CHOH–CH ), 0.86–0.91
2
3
1
3
(
m, 3H, CH3); C-NMR (CDCl + DMSO-d , 125 MHz):
3
6
1
Chloroform: methanol (92:8 v/v), yield 97%. H-NMR
CDCl , 500 MHz): 6.92 (br s, 1H, NH), 4.54 (d, J =
172 (O–C=O), 171.1 (HN–C=O), 65.5 (HC–OH), 56.1
(HC–NH), 34.5 (O=C–CH ), 30.2 (O=C–CH –CH ), 28
(
3
2
2
2
8
7
1
.39 Hz, 1H, CH–NH), 4.42 (m, 1H, CH–OH), 2.29 (t, J =
(CH ), 27.9 (CH ), 27.7 (CH ), 27.6 (CH ), 24.2 (CH ), 21
2 2 2 2 2
.62 Hz, 2H, O=C–CH ), 1.63 (m, 2H, CH ), 1.25 (m,
(CH ), 18.9 (HOHC–CH ), 12.6 (CH ); IR (KBr): 3538,
2
2
2
3
3
6H, CH ), 1.22 (d, J = 5.03 Hz, 3H, CHOH–CH ), 0.87 (t,
3315, 2919, 2849, 1711, 1649, 1543, 1281, 1209, 860, 673;
ESI–MS: m/z at 384.3 [M–H].
2
3
1
3
J = 6.56 Hz, 3H, CH3); C-NMR (CDCl , 100 MHz):
3

Med Chem Res
Oleoyl-L-threonine (3s)
119.8 (HC=CH), 66.8 (HC–OH), 56.9 (HC–NH), 39.5
O=C–NH–CH2), 32.5 (O=C–NH–CH –CH ), 31.8
(
2
2
1
Chloroform: methanol (92:8 v/v), yield 98%. H-NMR
CDCl , 500 MHz): 6.88 (s, 1H, NH), 5.31–5.37 (m, 2H,
(H C–HC=CH), 29.6 (CH ), 29.4 (CH ), 29.3 (CH ), 29.2
2 2 2 2
(
(CH ), 29.1 (CH ), 27.1 (CH ), 26.8 (CH ), 22.6 (CH ), 18
2 2 2 2 2
3
HC=CH), 4.48 (m, 1H, CH–NH), 4.42 (m, 1H, CH–OH),
.29 (t, J = 7.17 Hz, 2H, O=C–CH ), 2.01 (m, 4H,
(HOHC–CH ), 14 (CH ); IR (KBr): 3289, 3095, 2925,
3 3
2855, 1631, 1552, 1455, 1219, 1103, 978, 758; ESI–MS: m/
z at 521.03 [M + Na].
2
2
H C–HC=CH), 1.63 (m, 2H, CH ), 1.26–1.31 (m, 20H,
2
2
CH ), 1.21 (d, J = 6.25 Hz, 3H, CHOH–CH ), 0.88 (t, J =
2
3
1
3
6
.71 Hz, 3H, CH3); C-NMR (CDCl , 125 MHz): 175.2
3
(
2S, 3R)-2-(4-Nitro-cinnamamido)-3-hydroxy-N-(oleyl)
(
O–C=O), 174.3 (HN–C=O), 129.9 (HC=CH), 129.6
HC=CH), 67.5 (HC–OH), 57.7 (HC–NH), 36.3 (O=C–
butanamide (4b)
(
CH ), 33.8 (H C–HC=CH), 31.8 (O=C–CH –CH ), 29.7
1
2
2
2
2
Hexane: ethyl acetate (60:40, v/v), yield 80%. H-NMR
(
CH ), 29.5 (CH ), 29.3 (CH ), 29.2 (CH ), 29 (CH ), 27.2
2 2 2 2 2
(
(
CDCl , 500 MHz): 8.16–8.24 (m, 2H, Ar–H), 7.63–7.69
m, 2H, Ar–H), 7.14 (br s, 1H, NH), 6.90 (t, J = 5.52 Hz,
H, NH), 6.71 (d, J = 15.56 Hz, 1H,=CH), 6.21 (d, J =
5.56 Hz, 1H,=CH), 5.28–5.37 (m, 2H, HC = CH),
.41–4.46 (m, 1H, CH–NH), 4.31–4.33 (m, 1H, CH-–OH),
.18–3.30 (m, 2H, H C–NH), 1.94–2.01 (m, 4H,
H C–HC=CH), 1.49–1.51 (m, 2H, CH ), 1.25 (s, 22H,
3
(
CH ), 25.7 (CH ), 24.7 (CH ), 22.6 (CH ), 19.4 (HOHC–
2
2
2
2
CH ), 14 (CH ); IR (Neat): 3316, 2925, 2854, 1724, 1642,
3
3
1
1
4
3
1
540, 1461, 1248, 1119, 722; ESI–MS: m/z at 382.1
[
M–H].
2
General procedure for synthesis of compounds 4a–4s
2
2
CH ), 1.21 (d, J = 6.56 Hz, 3H, CHOH–CH ), 0.87 (t, J =
2
3
Fatty acid or Aromatic acid (3a–3s, 10.25 mmol) was
dissolved in ice-cold anhydrous dichloromethane (40 mL)
and to this oleyl amine (12.3 mmol), 1-ethyl-3-(3-dime-
thylaminopropyl) carbodiimide hydrochloride (EDC.
HCl, 12.3 mmol) and hydroxy benzotriazole (HOBt,
13
6.41 Hz, 3H, CH3); C-NMR (CDCl3, 125 MHz): 170.2
(
HN–C=O), 165.7 (HN–C=O), 147.9 (Ar–C–NO ), 140.8
2
(
HC=CH), 138.6 (Ar–C), 129.6 (H C–HC=CH), 128.2
2
(
H C–HC=CH), 127.6 (Ar–CH), 125.6 (Ar–CH), 124.1
2
(Ar–CH), 123.8 (Ar–CH), 122.9 (HC=CH), 66.6
1
5.38 mmol) were added successively at 0 °C and the
(
HC–OH), 57.7 (HC–NH), 39.3 (O=C–NH–CH ), 31.5
2
mixture was stirred for 12 h at room temperature. The
reaction was monitored using micro TLC (hexane: ethyl
acetate, 35:65, v/v). At the end of the reaction, the mix-
ture was dissolved in 75 mL of CHCl3, which was then
(
O=C–NH–CH –CH , H C–HC=CH)), 29.4 (CH ), 29.3
2
2
2
2
(
H C), 29.1 (CH ), 28.9 (CH ), 26.8 (CH ), 26.6 (CH ),
2 2 2 2 2
2
3
2.3 (CH ), 18.1 (HOHC–CH ), 13.6 (CH ); IR (KBr):
2 3 3
284, 3081, 2924, 2853, 1626, 1599, 1517, 1346, 973, 721;
washed by 5% NaHCO solution, saturated NaCl solution
3
ESI–MS: m/z at 566.1 [M + Na].
successively. The chloroform layer was dried with
anhydrous Na SO and the filtrate was dried under
2
4
reduced pressure. The crude mixture was purified by
silica gel chromatography, the title compounds were
obtained with 75–80% yield.
(2S, 3R)-2-(2-Indole-3-acetamido)-3-hydroxy-N-(oleyl)
butanamide (4c)
1
Hexane: ethyl acetate (60:40, v/v), yield 76%. H-NMR
(
(
2S, 3R)-2-Cinnamamido-3-hydroxy-N-(oleyl) butanamide
4a)
(CDCl , 400 MHz): 8.46 (br s, 1H, Ar–NH), 7.52 (d, J =
7.94 Hz, 1H, Ar–H), 7.33 (d, J = 8.06 Hz, 1H, Ar–H),
3
7
.18–7.22 (m, 1H, Ar–H), 7.10–7.13 (m, 1H, Ar–H),
1
Hexane: ethyl acetate (60:40, v/v), yield 78%. H-NMR
7.07–7.08 (s, 1H, Ar–H), 6.71 (t, J = 6.11 Hz, 1H, NH),
6.68 (d, J = 7.70 Hz, 1H, NH), 5.32–5.38 (m, 2H,
HC=CH), 4.29 (m, 1H, CH–NH), 4.27 (m, 1H, CH–OH),
3.77 (s, 2H, CH ), 3.06–3.17 (m, 2H, H C–NH), 1.98–2.03
(m, 4H, H C–HC=CH), 1.38 (m, 2H, CH ), 1.25 (m, 22H,
CH ), 0.94 (d, J = 6.35 Hz, 3H, CHOH–CH ), 0.87 (t, J =
6.72 Hz, 3H, CH3); C-NMR (CDCl3, 125 MHz): 172.8
(HN–C=O), 170.7 (HN–C=O), 136.3 (Ar–C–NH), 129.9
(H C–HC=CH), 129.7 (H C–HC=CH), 126.7 (Ar–C–CH),
123.6 (Ar–CH), 122.4 (Ar–CH), 119.8 (Ar–CH), 118.2
(Ar–CH), 111.5 (Ar–CH), 108.1 (Ar–C), 66.2 (HC–OH),
56.7 (HC–NH), 39.4 (O=C–NH–CH ), 33.3 (H C–C=O),
(
CDCl , 400 MHz): 7.64 (d, J = 15.65 Hz, 1H,=CH),
3
7
(
6
.48–7.51 (m, 2H, Ar–H), 7.34–7.35 (m, 3H, Ar–H), 7.20
d, J = 7.70 Hz, 1H, NH), 7.12 (t, J = 5.50 Hz, 1H, NH),
.59 (d, J = 15.65 Hz, 1H,=CH), 5.28–5.37 (m, 2H,
HC=CH), 4.52 (dd, J = 2.20, 7.70 Hz, 1H, CH–NH),
2
2
2
2
2
3
1
3
4
.39–4.44 (m, 1H, CH–OH), 3.18–3.28 (m, 2H, H C–NH),
2
1
.95–2.02 (m, 4H, H C–HC=CH), 1.48–1.52 (m, 2H,
CH ), 1.26(s, 22H, CH ), 1.20 (d, J = 6.48 Hz, 3H, CHOH–
CH ), 0.87 (t, J = 6.72 Hz, 3H, CH ); C-NMR (CDCl3,
00 MHz): 171(HN–C=O), 166.9 (HN–C=O), 141.9
HC=CH), 134.4 (Ar–C), 129.8 (H C–HC=CH), 129.6
H C–HC=CH, Ar–CH), 128.7 (Ar–CH), 127.8 (Ar–CH),
2
2
2
2
2
1
3
3
3
1
(
(
2
2
2
31.8 (H C–HC=CH, O=C–NH–CH –CH ), 29.7 (CH ),
2 2 2 2
2

Med Chem Res
2
9.6 (CH ), 29.4 (CH ), 29.3 (CH ), 29.2 (CH ), 27.1
CH ), 14 (CH ); IR (KBr): 3403, 3352, 2924, 2853, 1717,
2
2
2
2
3
3
(
(
CH ), 26.8 (CH ), 22.6 (CH ), 17.8 (HOHC–CH ), 14
1642, 1515, 1461, 1296, 1158, 745; ESI–MS: m/z at 535.01
[M + Na].
2
2
2
3
CH ); IR (KBr): 3395, 3029, 2952, 2832, 1642, 1540,
3
1
243, 1097, 726; ESI–MS: m/z at 548.04 [M + Na].
(
2S, 3R)-2-(3-Indole-3-propanamido)-3-hydroxy-N-(oleyl)
N-(2S, 3R)-(3-Hydroxy-1-(oleylamino)-1-oxobutan-2-yl)-
indole-2-carboxamide (4f)
butanamide (4d)
1
1
Hexane: ethyl acetate (60:40, v/v), yield 75%. H-NMR
CDCl , 400 MHz): 8.0 (br s, 1H, Ar–NH), 7.59 (d, J =
Hexane: ethyl acetate (60:40, v/v), yield 78%. H-NMR
(
(CDCl , 500 MHz): 9.61 (br s, 1H, Ar–NH), 7.59–7.65 (m,
3
3
7
(
.78 Hz, 1H, Ar–H), 7.33 (d, J = 7.93 Hz, 1H, Ar–H), 7.18
t, J = 7.93 Hz, 1H, Ar–H), 7.11 (d, J = 7.62 Hz, 1H,
Ar–H), 6.98 (s, 1H, Ar–H), 6.72 (br s, 1H, NH), 6.54 (br s,
H, NH), 5.31–5.37 (m, 2H, HC=CH), 4.25 (m, 2H,
CH–NH, CH–OH), 3.89 (br s, 1H, OH), 3.06–3.19 (m
overlap), 4H, H C–NH, CH ), 2.66 (t, J = 7.32 Hz, 2H,
1H, Ar–H), 7.47 (d, J = 7.62 Hz, 1H, Ar–H), 7.40 (d, J =
8.39 Hz, 1H, NH), 7.30 (t, J = 7.17 Hz, 1H, Ar–H),
7.12–7.15 (m, 1H, Ar–H), 7.06 (m, 1H, Ar–H), 6.88 (m,
1H, NH), 5.30–5.37 (m, 2H, HC=CH), 4.57 (m, 1H,
CH–NH), 4.49 (m, 1H, CH–OH), 4.18 (br s, 1H, OH),
1
(
3.19–3.28 (m, 2H,
C–HC=CH), 1.47 (m, 2H, CH
CH , CHOH–CH ), 0.87 (t, J = 6.71 Hz, 3H, CH ); C-
3
H
2
C–NH), 1.95–2.01 (m, 4H,
2
2
CH ), 1.95–2.05 (m, 4H, H C–HC=CH), 1.41 (m, 2H,
CH ), 1.25 (m, 22H, CH ), 0.94 (d, J = 6.41 Hz, 3H,
CHOH–CH ), 0.87 (t, J = 6.71 Hz, 3H, CH ); C-NMR
H
2
2
), 1.22–1.26 (m, 25H,
2
2
1
3
2
2
2
3
1
3
NMR (CDCl3, 125 MHz): 170.4 (HN–C=O), 162.2 (HN–
C=O), 136.6 (Ar–C–NH), 130 (O=C–C(NH)=CH), 129.7
3
3
(
1
CDCl3, 125 MHz): 173.8 (HN–C=O), 170.7 (HN–C=O),
36.2 (Ar–C–NH), 129.9 (H C–HC=CH), 129.7
(H C–HC=CH), 129.5 (H C–HC=CH), 127.2 (Ar–C),
2
2 2
(
(
H C–HC=CH), 126.9 (Ar–C–CH), 122 (Ar–CH), 121.5
Ar–CH), 119.3 (Ar–CH), 118.5 (Ar–CH), 114.3 (Ar–CH),
124.3 (Ar–CH), 121.8 (Ar–CH), 120.3 (Ar–CH), 111.9
(Ar–CH), 104.4 (Ar–CH), 66.7 (HC–OH), 57.5 (HC–NH),
2
1
11.1 (Ar–C), 66.5 (HC–OH), 56.8 (HC–NH), 39.4
39.4
O=C–NH–CH
29 (CH ), 26.9 (CH
(HOHC–CH
(O=C–NH–CH
2
),
31.6
), 29.3 (CH
), 26.7 (CH ), 22.4 (CH
); IR (KBr): 3357, 3245, 2922,
(H
), 29.1 (CH
), 18.4
2
C–HC=CH,
(
O=C–NH–CH ), 36.9 (H C–C=O), 32.5 (H C–HC=CH),
2
–CH ), 29.5 (CH
2
2
2
2
),
2
2
2
3
1.8 (O=C–NH–CH –CH ), 29.7 (CH ), 29.6 (CH ), 29.4
2
2
2
2
2
2
2
2
(
CH ), 29.2 (CH ), 27.1 (CH ), 26.8 (CH ), 22.6 (CH ),
3
), 13.9 (CH
3
2
2
2
2
2
2
1.2 (CH ), 17.8 (HOHC–CH ), 14 (CH ); IR (KBr): 3295,
2851, 1637, 1509, 1075, 721; ESI–MS: m/z at 534.2 [M +
2
3
3
3
049, 2922, 2852, 1629, 1540, 1213, 1097, 726; ESI–MS:
Na].
m/z at 562.2 [M + Na].
(
2S, 3R)-3-Hydroxy-N-(oleyl)-2-(2-phenylacetamido)
N-(2S, 3R)-(3-Hydroxy-1-(oleylamino)-1-oxobutan-2-yl)-
indazole-3-carboxamide (4e)
butanamide (4g)
1
1
Hexane: ethyl acetate (60:40, v/v), yield 77%. H-NMR
Hexane: ethyl acetate (60:40, v/v), yield 76%. H-NMR
(
(
CDCl , 400 MHz): 7.32–7.35 (m, 2H, Ar–H), 7.24–7.29
m, 3H, Ar–H), 6.82 (br s, 2H, NH), 5.33–5.38 (m, 2H,
HC=CH), 4.27–4.30 (m, 2H, CH–NH, CH–OH), 3.61 (s,
H, CH ), 3.13–3.19 (m, 2H, H C–NH), 1.96–2.03 (m, 4H,
H C–HC=CH), 1.39–1.44 (m, 2H, CH ), 1.25 (m, 22H,
(
CDCl , 500 MHz): 13.05 (br s, 1H, Ar–NH), 9.61 (br s,
H, NH), 8.30 (d, J = 8.24 Hz, 1H, Ar–H), 8.02 (br s, 1H,
NH), 7.57 (d, J = 8.54 Hz, 1H, Ar–H), 7.38 (t, J = 7.32 Hz,
H, Ar–H), 7.23 (t, J = 7.62 Hz, 1H, Ar–H), 5.29–5.36 (m,
H, HC=CH), 5.21 (br s, 1H, OH), 4.96 (t, J = 7.78 Hz,
H, CH–NH), 4.23 (m, 1H, CH–OH), 3.37–3.44 (m, 1H,
H C–NH), 3.17–3.22 (m, 1H, H C–NH), 1.95–2.01 (m, 4H,
H C–HC=CH), 1.35–1.48 (m, 2H, CH ), 1.15–1.24 (m,
2H, CH ), 0.99 (d, J = 6.10Hz, 3, CHOH–CH ), 0.86 (t, J
7.02 Hz, 3 H, CH3); C-NMR (CDCl 125 MHz): 171.7
HN–C=O), 164.3 (HN–C=O), 141.2 (Ar–C–NH), 138.4
O=C–(Ar)C=NH), 129.8 (H C–HC=CH), 129.7
H C–HC=CH), 126.9 (Ar–CH), 122.3 (Ar–CH), 121.5
Ar–CH), 111 (Ar–C), 67 (HC–OH), 60.2 (HC–NH), 39.9
O=C–NH–CH ), 31.8 (H C–HC=CH, O=C–NH–CH –
CH ), 29.7 (CH ), 29.6 (CH ), 29.4 (CH ), 29.2 (CH ), 29.1
3
3
1
2
1
2
1
2
2
2
2
CH ), 1.04 (d, J = 6.48 Hz, 3H, CHOH–CH ), 0.88 (t, J =
2
3
1
3
6
(
.61 Hz, 3H, CH3);
C-NMR (CDCl3, 75 MHz): 172.3
2
2
HN–C=O), 170.7 (HN–C=O), 134.5 (Ar–C–CH ), 130.8
2
2
2
(
H C–HC=CH), 129.9 (H C–HC=CH), 129.7 (Ar–CH),
29.1 (Ar–CH), 128.9 (Ar–CH), 128.7 (Ar–CH), 127.3
Ar–CH), 66.5 (HC–OH), 56.8 (HC–NH), 43.3 (Ar–
CH –C=O), 39.5 (O=C–NH–CH ), 32.6 (O=C–NH–CH –
2
=
2 2
2
3
1
3
1
(
3,
(
(
(
(
(
2
2
2
2
CH ), 31.9 (H C–HC=CH), 30.3 (CH ), 29.7 (CH ), 29.6
2
2
2
2
2
(
2
CH ), 29.5 (CH ), 29.3 (CH ), 29.2 (CH ), 28.9 (CH ),
2 2 2 2 2
7.2 (CH ), 26.8 (CH ), 23.7 (CH ), 22.9 (CH ), 22.6
2 2 2 2
2
2
2
(
CH ), 17.8 (HOHC–CH ), 14.1 (CH ); IR (KBr): 3354,
2 3 3
2
2
2
2
2
(
CH ), 27.1 (CH ), 27 (CH ), 22.6 (CH ), 19.3 (HOHC–
2 2 2 2

Med Chem Res
3
7
063, 2924, 2853, 1730, 1637, 1513, 1466, 1287, 1074,
19; ESI–MS: m/z at 509.1 [M + Na].
N-(2S, 3R)-(3-Hydroxy-1-(oleylamino)-1-oxobutan-2-yl)
hexanamide (4j)
1
Hexane: ethyl acetate (60:40, v/v), yield 78%. H-NMR
(
(
2S, 3R)-3-Hydroxy-2-(2-(4-methoxyphenyl) acetamido)-N-
oleyl) butanamide (4h)
(
CDCl , 400 MHz): 6.88 (br s, 1H, NH), 6.61 (br s, 1H,
3
NH), 5.29–5.38 (m, 2H, HC=CH), 4.28–4.35(m, 2H,
CH–NH, CH–OH), 3.22 (q, J = 6.48 Hz, 2H, H C–NH),
1
2
Hexane: ethyl acetate (60:40, v/v), yield 79%. H-NMR
2
.25 (t, J = 7.58 Hz, 2H, O=C–CH ), 1.97–2.01 (m, 4H,
2
(
(
CDCl , 400 MHz): 7.16 (d, J = 8.68 Hz, 2H, Ar–H), 6.87
d, J = 8.68 Hz, 2H, Ar–H), 6.75 (t, J = 5.25 Hz, 1H, NH),
.56 (d, J = 7.45 Hz, 1H, NH), 5.33–5.37 (m, 2H,
HC=CH), 4.28–4.33 (m, 1H, CH–NH), 4.24 (dd, J = 1.83,
.58 Hz, 1H, CH–OH), 3.79 (s, 3H, Ar–OCH ), 3.55 (s, 2H,
CH ), 3.14–3.20 (m, 2H, H C–NH), 1.97–2.03 (m, 4H,
H C–HC=CH), 1.43 (m, 2H, CH ), 1.25 (m, 22H, CH ),
.04 (d, J = 6.48 Hz, 3H, CHOH–CH ), 0.87 (t, J = 6.72
C-NMR (CDCl3, 125 MHz): 172.6
HN–C=O), 170.7 (HN–C=O), 158.8 (Ar–C–OCH3),
30.1 (Ar–C–CH2), 129.9 (H C–HC=CH), 129.6
H C–HC=CH), 126.2 (Ar–CH), 114.3 (Ar–CH), 66.2
HC–OH), 56.6 (HC–NH), 55.1 (Ar–C–O-CH ), 42.5 (Ar–
CH –C=O), 39.4 (O=C–NH–CH ), 31.8 (H C–HC=CH,
3
H C–HC=CH), 1.64 (m, 2H, CH ), 1.48 (m, 2H, CH ),
2
2
2
1
.25–1.32 (m, 26H, CH ), 1.14 (d, J = 6.48 Hz, 3H,
2
6
1
3
CHOH–CH ), 0.88 (t, J = 6.72 Hz, 6H, CH ); C-NMR
3
3
(
CDCl , 125 MHz): 174.2(HN–C=O), 170.8 (HN–C=O),
3
7
3
1
29.8 (H C–HC=CH), 129.6 (H C–HC=CH), 66.5
2 2
2
2
(
(
HC–OH), 56.6 (HC–NH), 39.6 (O=C–NH–CH ), 36.3
2
2
2
2
O=C–CH ), 32.5 (H C–HC=CH), 31.8 (O=C–CH –
2
2
2
1
3
CH ), 31.2 (CH ), 29.6 (CH ), 29.4 (CH ), 29.3 (CH ), 29.2
13
2
2
2
2
2
Hz, 3H, CH3);
(
CH ), 29.1 (CH ), 27.1 (CH ), 26.8 (CH ), 25.3 (CH ),
2 2 2 2 2
(
2
2.5 (CH ), 22.2 (CH ), 17.8 (HOHC–CH ), 14 (CH ), 13.8
2 2 3 3
1
2
(
CH ); IR (KBr): 3352, 2933, 2853, 1628, 1568, 1464,
3
(
(
2
1368, 1290, 1060, 698, 590; ESI–MS: m/z at 489.1 [M +
3
Na].
2
2
2
O=C–NH–CH –CH ), 29.7 (CH ), 29.6 (CH ), 29.4 (CH ),
2
2
2
2
2
N-(2S, 3R)-(3-Hydroxy-1-(oleylamino)-1-oxobutan-2-yl)
octanamide (4k)
2
9.2 (CH ), 27.1 (CH ), 26.8 (CH ), 22.6 (CH ), 17.8
2 2 2 2
(
HOHC–CH ), 14 (CH ); IR (KBr): 3292, 3099, 2924,
3 3
2
853, 1631, 1551, 1512, 1375, 1245, 1040, 753; ESI–MS:
1
Hexane: ethyl acetate (60:40, v/v), yield 80%. H-NMR
m/z at 539.06 [M + Na].
(
CDCl , 400 MHz): 6.86 (br s, 1H, NH), 6.59 (d, J = 7.45
3
Hz, 1H, NH), 5.30–5.38 (m, 2H, HC=CH), 4.32–4.38 (m,
1H, CH–NH), 4.29 (dd, J = 1.83, 7.7 Hz, 1H, CH–OH),
(
2S, 3R)-3-Hydroxy-2-(4-(4-methoxyphenyl) butanamide)-
N-(oleyl) butanamide (4i)
3.21 (q, J = 7.09 Hz, 2H, H C–NH), 2.25 (t, J = 7.7 Hz, 2H,
2
O=C–CH ), 1.97–2.07 (m, 4H, H C–HC=CH), 1.63 (m,
2
2
1
Hexane: ethyl acetate (60:40, v/v), yield 78%. H-NMR
2H, CH ), 1.48 (m, 2H, CH ), 1.27 (m, 30H, CH ), 1.14 d,
2 2 2
(
(
CDCl , 500 MHz): 7.07 (d, J = 8.54 Hz, 2H, Ar–H), 6.91
t, J = 5.18 Hz, 1H, NH), 6.82 (d, J = 8.54 Hz, 2H, Ar–H),
J = 6.6 Hz, 3H, CHOH–CH ), 0.88 (t, J = 6.6 Hz, 6H,
3
3
1
3
CH3); C-NMR (CDCl , 100 MHz): 174.3 (HN–C=O),
3
6
.67 (d, J = 7.17 Hz, 1H, NH), 5.32–5.37 (m, 2H,
171
(HN–C=O),
129.8
(H C–HC=CH),
129.6
2
HC=CH), 4.31–4.32 (m, 2H, CH–NH, CH–OH), 3.78 (s,
(H C–HC=CH), 66.3 (HC–OH), 56.4 (HC–NH), 39.4
2
3
7
4
H, Ar–OCH ), 3.18–3.24 (m, 2H, H C–NH), 2.57 (t, J =
(O=C–NH–CH ), 36.4 (O=C–CH ), 31.8 (H C–HC=CH),
3
2
2
2
2
.47 Hz, 2H, CH ), 2.24–2.28 (m, 2H, CH ), 1.96–2.02 (m,
31.6 (O=C–CH –CH ), 29.7 (CH ), 29.6 (CH ), 29.5
2
2
2 2 2 2
H, H C–HC=CH), 1.93 (t, J = 7.47 Hz, 2H, CH ), 1.47
(CH ), 29.4 (CH ), 29.3 (CH ), 29.2 (CH ), 29.1 (CH ),
2 2 2 2 2
2
2
(
3
m, 2H, CH ), 1.25 (m, 22H, CH ), 1.13 (d, J = 6.41 Hz,
28.9 (CH ), 27.1 (CH ), 26.8 (CH ), 25.6 (CH ), 22.6
2 2 2 2
(CH ), 22.5 (CH ), 17.8 (HOHC–CH ), 14 (CH ), 13.9
2 2 3 3
2
2
1
3
H, CHOH–CH ), 0.87 (t, J = 6.86 Hz, 3H, CH ); C-
3
3
NMR (CDCl3, 125 MHz): 173.9 (HN–C=O), 172.5 (HN–
C=O), 157.8 (Ar–C–OCH ), 133.1 (Ar–C–CH ), 130.1
(CH ); IR (KBr): 3361, 2923, 2853, 1637, 1558, 1464,
1378, 1290, 1073, 695, 590; ESI–MS: m/z at 517.1 [M +
3
3
2
(
H C–HC=CH), 129.8 (H C–HC=CH), 129.2 (Ar–CH),
Na].
2
2
1
26.2 (Ar–CH), 114.2 (Ar–CH), 113.7 (Ar–CH), 66.2
(
(
HC–OH), 56.7 (HC–NH), 55.1 (Ar–C–O–CH ), 42.4
N-(2S, 3R)-(3-Hydroxy-1-(oleylamino)-1-oxobutan-2-yl)-2-
propylpentanamide (4l)
3
H C–CH –C=O), 39.4 (O=C–NH–CH ), 35.4 (Ar–C–
2
2
2
CH ), 31.8 (H C–HC=CH, O=C–NH–CH –CH ), 29.6
2
2
2
2
1
(
CH ), 29.5 (CH ), 29.4 (CH ), 29.3 (CH ), 29.2 (CH ),
Hexane: ethyl acetate (60:40, v/v), yield 76%. H-NMR
2
2
2
2
2
2
9.1 (CH ), 27.3 (CH ), 27.1 (CH ), 26.8 (CH ), 22.6
(CDCl , 500 MHz): 7.03 (t, J = 5.64 Hz, 1H, NH), 6.73
2
2
2
2
3
(
3
CH ), 17.8 (HOHC–CH ), 14 (CH ); IR (KBr): 3284,
081, 2924, 2853, 1626, 1548, 1517, 1346, 1112. 973, 721;
(d, J = 7.47 Hz, 1H, NH), 5.30–5.37 (m, 2H, HC=CH),
4.32–4.39 (overlap m, 3H, CH–NH, CH–OH, OH), 3.21
2
3
3
ESI–MS: m/z at 567.2 [M + Na].
(q, J = 7.17 Hz, 2H, H C–NH), 2.17–2.23 (m, 1H,
2

Med Chem Res
O=C–CH ), 1.96–2.06 (m, 4H, H C–HC=CH), 1.55–1.62
(CH ), 29.2 (CH ), 29.1 (CH ), 27.1 (CH ), 26.8 (CH ),
2
2
2
2
2
2
2
(
m, 2H, CH ), 1.46–1.48 (m, 2H, CH ), 1.37–1.42 (m, 2H,
25.6 (CH ), 22.5 (CH ), 17.8 (HOHC–CH ), 14(CH ); IR
2 2 3 3
2
2
CH ), 1.26 (m, 26H, CH ), 1.14 (d, J = 6.4 Hz, 3H,
(KBr): 3371, 2933, 2853, 1632, 1558, 1464, 1368, 1290,
1063, 695, 590; ESI–MS: m/z at 559.1 [M + Na].
2
2
1
3
CHOH–CH ), 0.86–0.91 (m, 9H, CH ); C-NMR (CDCl3,
3
3
7
5 MHz): 177.3 (HN–C=O), 171 (HN–C=O), 129.9 (H C–
2
HC=CH), 129.7 (H C–HC=CH), 66.3 (HC–OH), 56.2
N-(2S, 3R)-(3-Hydroxy-1-(oleylamino)-1-oxobutan-2-yl)
dodecanamide (4o)
2
(
HC–NH), 47.1 (O=C–CH), 39.4 (O=C–NH–CH ), 35.3
2
(
(
O=C–CH–CH2),
H C–HC=CH), 31.8 (CH ), 29.7 (CH ), 29.6 (CH ), 29.5
2
35.2
(O=C–CH–CH2),
32.5
1
Hexane: ethyl acetate (60:40, v/v), yield 78%. H-NMR
2
2
2
(
CH ), 29.4 (CH ), 29.3 (CH ), 29.2 (CH ), 27.1 (CH ),
(CDCl , 400 MHz): 6.85 (t, J = 5.38 Hz, 1H, NH), 6.57 (d,
2
2
2
2
2
3
2
6.9 (CH ), 22.6 (CH ), 20.7 (CH ), 17.7 (HOHC–CH ), 14
J = 7.58 Hz, 1H, NH), 5.30–5.38 (m, 2H, HC=CH),
4.33–4.38 (m, 1H, CH–NH), 4.28 (dd, J = 1.95, 7.70 Hz,
2
2
2
3
(
CH ); IR (KBr): 3279, 3101, 2923, 2853, 1637, 1551,
3
1
463, 1377, 718; ESI–MS: m/z at 517.04 [M + Na].
1H, CH–OH), 3.21 (q, J = 6.61 Hz, 2H, H C–NH), 2.25 (t,
2
J = 7.71 Hz, 2H, O=C–CH2), 1.97–2.04 (m, 4H,
H C–HC=CH), 1.59–1.65 (m, 2H, CH ), 1.46–1.49 (m,
N-(2S, 3R)-(3-Hydroxy-1-(oleylamino)-1-oxobutan-2-yl)
undec-10-enamide (4m)
2
2
2H, CH ), 1.25 (m, 38H, CH ), 1.14 (d, J = 6.48 Hz, 3H,
2
2
1
3
CHOH–CH ), 0.88 (t, J = 6.61 Hz, 6H, CH ); C-NMR
3
3
1
Hexane: ethyl acetate (60:40, v/v), yield 75%. H-NMR
(CDCl , 125 MHz): 174.4 (HN–C=O), 171.1 (HN–C=O),
3
(
CDCl , 500 MHz): 6.96 (s, 1H, NH), 6.68 (s, 1H, NH),
129.9 (H C–HC=CH), 129.6 (H C–HC=CH), 66.3
3
2
2
5
4
3
.75–5.83 (m, 1H,=CH), 5.33–5.36 (m, 2H, HC=CH),
(HC–OH), 56.4 (HC–NH), 39.4 (O=C–NH–CH ), 36.4
2
.91–4.99 (m, 2H,=CH ), 4.32 (m, 2H, CH–NH, CH–OH),
(O=C–CH ), 32.5 (H C–HC=CH), 31.8 (O=C–CH –
2
2
2
2
.19–3.23 (m, 2H, H C–NH), 2.25 (t, J = 6.86 Hz, 2H,
CH ), 29.7 (CH ), 29.6 (CH ), 29.5 (CH ), 29.4 (CH ), 29.3
2
2 2 2 2 2
O=C–CH2), 1.96–2.03 (m, 6H, H C–HC = CH,
(CH ), 29.2 (CH ), 27.1 (CH ), 26.8 (CH ), 25.7 (CH ),
2 2 2 2 2
2
H C–HC=CH ), 1.62 (m, 2H, CH ), 1.47 (m, 2H, CH ),
22.6 (CH ), 17.8 (HOHC–CH ), 14 (CH ); IR (KBr): 3361,
2 3 3
2
2
2
2
1
.27 (m, 32H, CH ), 1.13 (d, J = 6.41 Hz, 3H, CHOH–
2923, 2853, 1637, 1558, 1464, 1378, 1290, 1073, 695;
ESI–MS: m/z at 573.4 [M + Na].
2
1
3
CH ), 0.87 (t, J = 7.02 Hz, 3H, CH ); C-NMR (CDCl3,
3
3
1
00 MHz): 174.3 (HN–C=O), 170.9 (HN–C=O), 138.9
H C–HC=CH), 129.8 (H C–HC=CH), 129.6
H C–HC=CH), 114 (H C–HC=CH), 66.4 (HC–OH), 56.5
(
(
(
(
N-(2S, 3R)-(3-Hydroxy-1-(oleylamino)-1-oxobutan-2-yl)
tetradecanamide (4p)
2
2
2
2
HC–NH), 39.4 (O=C–NH–CH ), 36.4 (O=C–CH ), 33.7
H C–HC=CH), 32.5 (H C–HC=CH), 31.8 (O=C–CH –
2
2
1
Hexane: ethyl acetate (60:40, v/v), yield 77%. H-NMR
2
2
2
CH ), 29.6 (CH ), 29.4 (CH ), 29.3 (CH ), 29.2 (CH ), 28.9
(CDCl , 400 MHz): 6.99 (br s, 1H, NH), 6.74 (d, J = 7.21
2
2
2
2
2
3
(
CH ), 28.8 (CH ), 27.1 (CH ), 26.8 (CH ), 25.6 (CH ),
Hz, 1H, NH), 5.30–5.38 (m, 2H, HC=CH), 4.34 (m, 2H,
2
2
2
2
2
2
2.6 (CH ), 17.8 (HOHC–CH ), 14 (CH ); IR (KBr): 3358,
CH–NH, CH–OH), 3.18–3.25 (m, 2H, H C–NH), 2.26 (t, J
2
3
3
2
2
922, 2851, 1635, 1557, 1509, 1291, 1074, 910, 518;
= 7.82 Hz, 2H, O=C–CH2), 1.96–2.03 (m, 4H,
H C–HC=CH), 1.63 (m, 2H, CH ), 1.48 (m, 2H, CH ),
ESI–MS: m/z at 557.3 [M + Na].
2
2
2
1
.25 (m, 42H, CH ), 1.14 (d, J = 6.35 Hz, 3H, CHOH–
2
1
3
N-(2S, 3R)-(3-Hydroxy-1-(oleylamino)-1-oxobutan-2-yl)
undecanamide (4n)
CH ), 0.88 (t, J = 6.6 Hz, 6H, CH ); C-NMR (CDCl3,
3
3
125 MHz): 174.3 (HN–C=O), 170.9 (HN–C=O), 129.8
H C–HC=CH), 129.6 (H C–HC=CH), 66.4 (HC–OH),
(
2
2
1
Hexane: ethyl acetate (60:40, v/v), yield 76%. H-NMR
56.6 (HC–NH), 39.4 (O=C–NH–CH ), 36.4 (O=C–CH ),
2 2
(
CDCl , 500 MHz): 6.89 (br s, 1H, NH), 6.62 (d, J = 7.32
31.8 (H C–HC=CH, O=C–CH –CH ), 29.6 (CH ), 29.5
2 2 2 2
3
Hz, 1H, NH), 5.30–5.38 (m, 2H, HC=CH), 4.29–4.35 (m,
(CH ), 29.4 (CH ), 29.3 (CH ), 29.2 (CH ), 29.1 (CH ),
2 2 2 2 2
2
H, CH–NH, CH–OH), 4.12 (br s, 1H, OH), 3.21 (q, J =
27.1 (CH ), 26.8 (CH ), 25.6 (CH ), 22.6 (CH ), 17.8
2 2 2 2
5
.45 Hz, 2H, H C–NH), 2.25 (t, J = 7.62 Hz, 2H,
(HOHC–CH ), 14 (CH ); IR (KBr): 3429, 3354, 2927,
3 3
2
O=C–CH ), 1.97–2.02 (m, 4H, H C–HC=CH), 1.63 (m,
2851, 1658, 1533, 1475, 1293, 1071, 720; ESI–MS: m/z at
601.06 [M + Na].
2
2
2
H, CH ), 1.48 (m, 2H, CH ), 1.25 (m, 36H, CH ), 1.14 (d,
2 2 2
J = 6.56 Hz, 3H, CHOH–CH ), 0.87 (t, J = 6.86 Hz, 6H,
3
1
3
CH3); C-NMR (CDCl3, 125 MHz): 174.3 (HN–C=O),
70.9 (HN–C=O), 129.8 (H C–HC=CH), 129.6
N-(2S, 3R)-(3-Hydroxy-1-(oleylamino)-1-oxobutan-2-yl)
hexadecanamide (4q)
1
2
(
(
H C–HC=CH), 66.4 (HC–OH), 56.5 (HC–NH), 39.4
2
1
O=C–NH–CH ), 36.3 (O=C–CH ), 31.8 (H C–HC=CH,
Hexane: ethyl acetate (60:40, v/v), yield 79%. H-NMR
2
2
2
O=C–CH –CH ), 29.6 (CH ), 29.5 (CH ), 29.4 (CH ), 29.3
(CDCl , 500 MHz): 6.86 (t, J = 5.49 Hz, 1H, NH), 6.58
2
2
2
2
2
3

Med Chem Res
(
d, J = 7.62 Hz, 1H, NH), 5.31–5.37 (m, 2H, HC=CH),
CH ), 29.7 (CH ), 29.6 (CH ), 29.4 (CH ), 29.2 (CH ), 27.1
2 2 2 2 2
4
.33–4.37 (m, 1H, CH–NH), 4.28 (dd, J = 1.98, 7.78 Hz,
(CH ), 26.8 (CH ), 25.6 (CH ), 22.6 (CH ), 17.8 (HOHC–
2 2 2 2
1
H, CH–OH), 3.21 (q, J = 5.95 Hz, 2H, H C–NH), 2.25 (t,
CH ), 14 (CH ); IR (KBr): 3418, 3254, 2934, 2861, 1632,
3 3
2
J = 7.47 Hz, 2H, O=C–CH2), 1.98–2.02 (m, 4H,
H C–HC=CH), 1.63 (m, 2H, CH ), 1.48 (m, 2H, CH ),
1543, 1465, 1276, 1071, 720; ESI–MS: m/z at 655.2 [M +
Na].
2
2
2
1
0
.25 (m, 46H, CH ), 1.14 (d, J=6.56 Hz, 3H, CHOH–CH ),
2 3
1
3
.88 (t, J = 6.86 Hz, 6H, CH3); C-NMR (CDCl , 100
1,2,3,4,6-Penta-O-acetyl-β-D-galactopyranoside (5)
3
MHz): 173.9 (HN–C=O), 170.7 (HN–C=O), 129.6 (H C–
2
HC=CH), 129.5 (H C–HC=CH), 66.2 (HC–OH), 56.5
Compound was prepared by our previous protocol (Vudh-
2
1
(
(
(
(
HC–NH), 39.2 (O=C–NH–CH ), 36.2 (O=C–CH ), 31.6
giri et al. 2017). H-NMR (400 MHz, CDCl ) δ 5.71 (d, J =
2
2
3
H C–HC=CH, O=C–CH –CH ), 29.5 (CH2), 29.4
8.31 Hz, 1H, Gal-1), 5.43 (m, 1H, Gal-4), 5.33 (t, J = 8.31
Hz, 1H, Gal-2), 5.09 (dd, J = 3.42, 10.39 Hz, 1H, Gal-3),
4.1–4.19 (m, 2H, Gal-6), 4.04–4.08 (m, 1H, Gal-5), 2.16 (s,
3H, O=C–CH ), 2.12 (s, 3H, O=C–CH ), 2.04 (s, 6 H,
2
2
2
CH ), 29.3 (CH ), 29.2 (CH ), 29.1 (CH ), 29 (CH ), 26.9
2
2
2
2
2
CH ), 26.6 (CH ), 25.5 (CH ), 22.4 (CH ), 17 (HOHC–
2
2
2
2
CH ), 13.8 (CH ); IR (KBr): 3562, 3325, 2932, 2861, 1656,
3
3
3
3
1
3
1
543, 1468, 1292, 1081, 720; ESI–MS: at m/z 629.1 [M +
O=C–CH ), 1.99 (s, 3H, O=C–CH ); C-NMR (100
3
3
Na].
MHz, CDCl ) δ 170(H C–C=O), 169.8 (H C–C=O), 169.6
3 3 3
(
H C–C=O), 169.1 (H C–C=O), 168.7 (H C–C=O), 91.8
3 3 3
N-(2S, 3R)-(3-Hydroxy-1-(oleylamino)-1-oxobutan-2-yl)
octadecanamide (4r)
(C-1), 71.4 (C-3), 70.5 (C-5), 67.6 (C-2), 66.6 (C-4), 60.8
(C-6), 20.5 (H C–C=O), 20.4 (H C–C=O), 20.3
3
3
(
H C–C=O); IR (CHCl ) 3027, 2969, 2951, 2907,1756,
3 3
1
Hexane: ethyl acetate (60:40, v/v), yield 78%. H-NMR
1743, 1422, 1371, 1322, 1225, 1067,1048, 912, 756, 704,
641,599. HRMS (ESI) m/z [M + Na]-calc. for
C H O Na 413.10543 found 413.10449.
(
CDCl , 500 MHz): 6.84 (t, J = 5.18 Hz, 1H, NH), 6.58 (d,
J = 7.47 Hz, 1H, NH), 5.32–5.37 (m, 2H, HC=CH),
3
1
6 22 11
4
.34–438 (m, 1H, CH–NH), 4.27 (dd, J = 1.95, 7.62 Hz,
1
H, CH–OH), 3.21 (q, J = 6.71 Hz, 2H, H C–NH), 2.26 (t,
2,3,4,6-Tetra-O-acetyl-galactopyranose hemiacetal (6)
2
J = 7.47 Hz, 2H, O=C–CH2), 1.97–2.04 (m, 4H,
H C–HC=CH), 1.63 (m, 2H, CH ), 1.48 (m, 2H, CH ),
Compound was prepared by previous protocol (Manzo
2
2
2
1
1
.25 (m, 50H, CH ), 1.14 (d, J = 6.56 Hz, 3H, CHOH–
et al. 2012). H-NMR (500 MHz, CDCl ) δ 5.54 (t, J =
2
3
1
3
CH ), 0.88 (t, J = 6.86 Hz, 6H, CH ); C-NMR (CDCl3,
9.9 Hz, 1H, Gal-4), 5.46 (d, J = 2.8 Hz, 1H, Gal-2), 5.09
(t, J = 9.4 Hz, 1H, Gal-3), 4.8–4.9 (m, 1H, Gal-1),
4.22–4.29 (m, 2H, Gal-6), 4.10–4.16 (m, 1H, Gal-5), 2.10
(s, 3H, O=C–CH ), 2.08 (s, 3H, O=C–CH ), 2.04 (s, 3H,
3
3
1
00 MHz): 174.3 (HN–C=O), 171.0 (HN–C=O), 129.8
(
H C–HC=CH), 129.6 (H C–HC=CH), 66.3 (HC–OH),
2
2
5
3
6.4 (HC–NH), 39.4 (O=C–NH–CH ), 36.4 (O=C–CH ),
2 2
3
3
1
3
1.8 (H C–HC=CH, O=C–CH –CH ), 29.6 (CH ), 29.4
O=C–CH ), 2.02 (s, 3H, O=C–CH ); C-NMR (75
2
2
2
2
3
3
(
CH ), 29.3 (CH ), 29.2 (CH ), 29.2 (CH ), 27.1 (CH ),
MHz, CDCl ) δ 171.06 (H C–C=O), 170.5 (H C–C=O),
3 3 3
2
2
2
2
2
2
6.8 (CH ), 25.6 (CH ), 22.6 (CH ), 17.8 (HOHC–CH ), 14
170.3 (H C–C=O), 169.7 (H C–C=O), 95.3 (C-1), 89.9
2
2
2
3
3 3
(
1
CH ); IR (KBr): 3409, 3354, 2922, 2851, 1637, 1553,
465, 1292, 1071, 720; ESI–MS: m/z at 657.3 [M + Na].
(C-3), 72.9 (C-5), 72.4 (C-5), 71.8 (C-2), 71.1 (C-2), 69.9
(C-4), 68.4 (C-4), 66.9 (C-6), 61.9 (C-6), 30.1
3
(
H C–C=O), 29.6 (H C–C=O), 20.6 (H C–C=O); IR
3 3 3
N-(2S, 3R)-(3-Hydroxy-1-(oleylamino)-1-oxobutan-2-yl)
oleamide (4s)
(CHCl ) 3460.6, 3024.4, 1748.8, 1369.5, 1235.7, 1038.6,
3
756;
HRMS
(ESI)
m/z
[M + Na]-calc.
for
C H O Na=371.09487 found 371.09459.
1
4
20 10
1
Hexane: ethyl acetate (60:40, v/v), yield 77%. H-NMR
(
5
4
CDCl , 500 MHz): 6.86 (s, 1H, NH), 6.57 (s, 1H, NH),
.30–5.37 (m, 4H, HC=CH), 4.29–4.35 (m, 1H, CH–NH),
.28 (m, 1H, CH–OH), 4.07 (s, 1H, OH), 3.19–3.23 (m, 2H,
2,3,4,6-Tetra-O-acetyl-α-galactopyranosyl
trichloroacetimidate (7)
3
H C–NH), 2.25 (t, J = 7.62 Hz, 2H, O=C–CH ), 1.98–2.02
2,3,4,6-Tetra-O-acetyl-galactopyranose hemiacetal (2)
(2 g, 5.75 mmol) was treated with trichloroacetonitrile (57.5
mmol) and 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU,
1.15 mmol) in anhydrous dichloromethane (30 mL) and the
contents were stirred for 2 h at room temperature. After 2 h,
the reaction mixture was concentrated under reduced pres-
sure and purified by silica gel column chromatography.
The required product was eluted in solvent mixture (20: 80,
2
2
(
m, 8H, H C–HC=CH), 1.63 (m, 2H, CH ), 1.48 (m, 2H,
2
2
CH ), 1.26–1.30 (m, 42H, CH ), 1.14 (d, J = 6.41 Hz, 3H,
2
2
1
3
CHOH–CH ), 0.88 (t, J = 6.56 Hz, 3H, CH ); C-NMR
3
3
(
CDCl , 100 MHz): 174.3 (HN–C=O), 171.1 (HN–C=O),
3
1
29.9 (H C–HC=CH), 129.6 (H C–HC=CH), 66.3
2 2
(
(
HC–OH), 56.4 (HC–NH), 39.4 (O=C–NH–CH ), 36.4
2
O=C–CH ), 32.5 (H C–HC=CH), 31.8 (O=C–CH –
2
2
2

Med Chem Res
1
EtOAc: hexane, v/v) with good yield (78%, 2.20 g). H-
C=O), 167.4 (HN–C=O), 142.2 (HC=CH), 135.2 (Ar–C),
130.3 (H C–HC=CH), 130.2 (H C–HC=CH, Ar–CH),
NMR (400 MHz, CDCl ) δ 8.6 (s, 1H,=NH), 6.61 (d, J =
3
2
2
2
2
.32 Hz, 1H, Gal-1), 5.57 (br s, 1H, Gal-4), 5.34–5.45 (m,
H, Gal-3, 2), 4.45 (t, J = 6.35 Hz, 1H, Gal-5), 4.06–4.19
129.3 (Ar–CH), 128.3 (Ar–CH), 120.5 (HC=CH), 102.6
(C-1), 76.1 (C-3), 74.9 (C-5), 74 (C-2), 71.7 (C-4), 69.6
(HC–OH), 62.3 (C-6), 58.2 (HC–NH), 40.1 (O=C–NH-
CH ), 32.3 (O=C–NH–CH –CH ), 30.2 (H C–HC=CH),
(
m, 2H, Gal-6), 2.18 (s, 3H, O=C–CH ), 2.02 (2 s, 9H,
3
1
3
O=C–CH3); C-NMR (CDCl , 100 MHz): 170.1 (H C–
3
3
2
2
2
2
C=O), 169.9 (H C–C=O), 169.8 (H C–C=O), 169.7
30.1 (CH ), 29.9 (CH ), 29.7 (CH ), 27.6 (CH ), 27.4
3
3
2 2 2 2
(
H C–C=O), 160.6 (O–C=NH), 93.3 (C–Cl ), 90.5 (C-1),
(CH ), 23.1 (CH ), 16.3 (HOHC–CH ), 14.3 (CH ); IR
2 2 3 3
3
3
6
2
3
8.8 (C-3), 67.3 (C-5), 67.2 (C-2), 66.7 (C-4), 61 (C-6),
(KBr): 3289, 3095, 2925, 2855, 1631, 1552, 1455, 1366,
1219, 978, 758; HRMS (ESI) m/z [M+H]-calc. for
C H O N = 661.44224 found 661.44348.
0.4 (H C–C=O), 20.3 (H C–C=O); IR (CHCl ) 3478,
3
3
3
347, 2135, 1748.8, 1676.44, 1371, 1218, 1073, 756.
3
7 61 8 2
General procedure for synthesis of compounds 8a–8s
(2S, 3R)-2-(3-(4-Nitrophenyl) acryl amido)-N-(oleyl)-3-((β-
D-galactopyranosyl) oxy) butanamide (8b)
Imidate (7) (1 mmol), compounds 4a–4i (1.2 mmol) and
molecular sieves (4 Å) were taken in freshly distilled
dichloromethane (10 mL) at 0 °C and the contents were
stirred for 30 min under nitrogen atmosphere. To this
reaction mixture, trimethylsilyl trifluoromethanesulfonate
1
Chloroform: methanol (95: 5, v/v), yield 70%. H-NMR
(CDCl3 + CD OD, 300 MHz): 8.23 (dd, J = 8.49, 21.33 Hz,
3
2H, Ar–H), 7.73 (dd, J = 8.49, 21.33 Hz, 2H, Ar–H), 7.65
(d, J = 15.86 Hz, 1H,=CH), 6.89 (t (overlap), J = 15.48 Hz,
2H,=CH, NH), 6.28 (d, J = 12.46 Hz, 1H, NH), 5.32–5.37
(m, 2H, HC=CH), 4.68 (d, J = 4.72 Hz, 1H, CH–NH),
4.33–4.39 (m, 1H, CH–OH), 4.24–4.27 (m, 1H, Gal-1),
3.81–3.90 (m, 1H, Gal-4), 3.76–3.77 (m, 1H, Gal-6),
3.72–3.73 (m, 1H, Gal-6), 3.53–3.58 (m, 1H, Gal-2),
3.47–3.51 (m (overlap), 2H, Gal-3 & 5), 3.16–3.28 (m, 2H,
H C–NH), 1.95–2.02 (m, 4H, H C–HC=CH), 1.51 (m, 2H,
(
TMSOTf, 0.4 mmol) was added dropwise at 0 °C and
slowly allowed the reaction mixture to room temperature
and magnetically stirred for overnight. After completion of
all the starting materials, the reaction mixture was filtered
and dissolved in CHCl (30 mL). The organic layer was
3
extracted with aq. NaHCO solution, dried over anhydrous
3
Na SO and concentrated under reduced pressure. This
2
4
2
2
crude mixture was dissolved in dry methanol that contained
a catalytic amount of sodium methoxide. The reaction
mixture was allowed to stir at ambient temperature for 30
min under nitrogen. After total consumption of starting
material, the reaction mixture was neutralized by the addi-
CH ), 1.27–1.34 (m (overlap), 25H, CH , CHOH–CH ),
2
2
3
1
3
0.88 (t, J = 6.23 Hz, 3H, CH3);
C-NMR (CDCl3
CD OD, 75 MHz): 170.2 (HN–C=O), 166.8 (HN–C=O),
+
3
148.7 (Ar–C–NO ), 142.4 (HC=CH), 139.2 (Ar–C), 130.6
2
(H C–HC=CH), 130.2 (H C–HC=CH), 129 (Ar–CH),
2
2
+
tion of Amberlite IR-120 (H ) resin. Then, the reaction
126.5 (Ar–CH), 125.1 (Ar–CH), 124.5 (Ar–CH), 123.6
(HC=CH), 102.7 (C-1), 76.1 (C-3), 74.9 (C-5), 74 (C-2), 71
(C-4), 69.7 (HC–OH), 62.4 (C-6), 58.4 (HC–NH), 40.2
(O=C–NH–CH2), 32.3 (O=C–NH–CH –CH ), 30.1
mixture was filtered and concentrated under reduced pres-
sure to obtain a crude product. This crude product was
purified by silica gel chromatography using chloroform:
methanol solvent mixture to give title compounds as white
solids with 65–74% yields.
2
2
(H C–HC=CH), 29.9 (CH ), 29.7 (CH ), 27.6 (CH ), 27.4
2
2
2
2
(CH ), 23.1 (CH ), 16.4 (HOHC–CH ), 14.3 (CH ); IR
2
2
3
3
(KBr): 3284, 3081, 2924, 2853, 1626, 1599, 1517, 1346,
(
2S, 3R)-2-Cinnamamido-N-(oleyl)-3-((β-D-galactopyrano-
973, 721; HRMS (ESI) m/z [M+H]-calc. for C H O N
3
7 60 10 3
syl) oxy) butanamide (8a)
= 706.42732 found 706.42840.
1
Chloroform: methanol (95: 5, v/v), yield 72%. H-NMR
CDCl3 + CD OD, 300 MHz): 7.61 (d, J = 15.95 Hz, 1H,
(2S, 3R)-2-(2-(1H-Indol-3-yl) acetamido)-N-(oleyl)-3-((β-D-
galactopyranosyl) oxy) butanamide (8c)
(
3
=
CH), 7.55–7.57 (m, 2H, Ar–H), 7.38–7.40 (m, 3H,
1
Ar–H), 6.67 (d, J = 15.95 Hz, 1H,=CH), 5.32–5.39 (m, 2H,
HC=CH), 4.70 (d, J = 4.12 Hz, 1H, CH–NH), 4.36–4.39
Chloroform: methanol (95: 5, v/v), yield 74%. H-NMR
(CDCl3 + CD OD, 400 MHz): 7.51–7.57(m, 1H, Ar–H),
3
(
m, 1H, CH–OH), 4.26–4.30 (m, 1H, Gal-1), 3.90–3.95 (m,
H, Gal-4), 3.86 (m, 1H, Gal-6), 3.75–3.78 (m, 1H, Gal-6),
.57–3.60 (m, 1H, Gal-2), 3.52–3.54 (m (overlap), 2H, Gal-
7.35–7.39 (m, 1H, Ar–H), 7.24 (s, 1H, Ar–H), 7.08–7.16 (m,
2H, Ar–H), 5.34–5.38 (m, 2H, HC=CH), 4.55 (m, 1H,
HC–NH), 4.29 (m, 1H, HC–OH), 4.16 (m, 1H, Gal-1), 4.06
(m, 1H, Gal-4), 3.83 (m, 2H, Gal-6), 3.76 (s, 2H, CH2),
3.65–3.72 (m, 1H, Gal-2), 3.46 (m (overlap), 2H, Gal-3
1
3
3
& 5), 3.18–3.27 (m, 2H, H C–NH), 1.97–2.04 (m, 4H,
2
H C–HC=CH), 1.53 (m, 2H, CH ), 1.22–1.34 (m, (over-
2
2
lap), 25H, CH , CHOH–CH ), 0.88 (t, J = 6.32 Hz, 3H,
& 5), 3.04–3.15 (m, 2H, H C–NH), 2.02–2.19 (m,
2
3
2
1
3
CH3); C-NMR (CDCl3 + CD OD, 75 MHz): 170.4 (HN–
4H, H C–HC=CH), 1.27 (m, 24H, CH ), 1.09 (m, 3H,
3
2
2

Med Chem Res
1
3
CHOH–CH ), 0.89 (m, 3H, CH ); C-NMR (CDCl3
1H, Gal-4), 3.88–3.91 (m, 1H, Gal-6), 3.74–3.78 (m, 1H,
Gal-6), 3.63–3.65 (m, 1H, Gal-2), 3.55–3.58 (m (overlap),
3
3
CD OD, 75 MHz): 173.8 (HN–C=O), 170 (HN–C=O),
+
3
1
37.2 (Ar–C–NH), 130.3 (H C–HC=CH), 130.3
2H, Gal-3 & 5), 3.21–3.32 (m, 2H, H C–NH), 2.01 (m, 4H,
2
2
(
H C–HC=CH), 127.5 (Ar–C–CH), 124.7 (Ar–CH), 122.3
2
H C–HC=CH), 1.54 (m, 2H, CH ), 1.27–1.30 (m (over-
2
2
(
1
Ar–CH), 120.8 (Ar–CH), 119.7 (Ar–CH), 118 (Ar–CH),
12 (Ar–C), 102.8 (C-1), 76 (C-3), 74.8 (C-5), 74 (C-2), 71.7
lap), 25H, CH , CHOH–CH ), 0.88 (t, J = 6.96 Hz, 3H,
2 3
1
3
CH3); C-NMR (CDCl3 + CD OD, 75 MHz): 170.4 (HN–
3
(
(
C-4), 69.5 (HC–OH), 62.2 (C-6), 58.8 (HC–NH), 40.1
O=C–NH–CH ), 33.6 (H C–C=O), 32.4 (H C–HC=CH),
C=O), 163.8 (HN–C=O), 142 (Ar–C–NH), 138.2 (O=C–
(Ar)C=NH), 130.3 (H C–HC=CH), 130.2 (H C–HC=CH),
2
2
2
2
2
3
0.2 (O=C–NH–CH –CH ), 30.1 (CH ), 29.9 (CH ), 29.7
127.4 (Ar–CH), 123.1 (Ar–CH), 122.3 (Ar–CH), 110.9
(Ar–C), 103.3 (C-1), 76.2 (C-3), 75.7 (C-5), 73.9 (C-2),
71.6 (C-4), 69.7 (HC–OH), 62.3 (C-6), 57.8 (HC–NH), 40.2
(O=C–NH–CH ), 32.3 (H C–HC=CH), 30.1 (O=C–NH–
2
2
2
2
(
CH ), 29.6 (CH ), 27.6 (CH ), 27.3 (CH ), 23.1 (CH ), 16.3
2 2 2 2 2
(
HOHC–CH ), 14.3 (CH ); IR (KBr): 3295, 3049, 2922,
3 3
2
+
852, 1629, 1540, 1213, 1097, 726; HRMS (ESI) m/z [M
H]-calc. for C H O N = 688.45314 found 608.45370.
2
2
CH –CH ), 29.9 (CH ), 29.7 (CH ), 27.6 (CH ), 27.4, 23.1
3
8
62
8
3
2 2 2 2 2
(
CH ), 16.8 (HOHC–CH ), 14.3 (CH ); IR (KBr): 3403,
2 3 3
(
(
2S, 3R)-2-(3-(1H-Indol-3-yl) propanamido)-N-(oleyl)-3-
(β-D-galactopyranosyl) oxy) butanamide (8d)
3352, 2924, 2853, 1717, 1642, 1515, 1461, 1296, 1158,
745; HRMS (ESI) m/z [M+H]-calc. for C H O N =
3
6 59 8 4
675.43274 found 675.43313.
1
Chloroform: methanol (95: 5, v/v), yield 74%. H-NMR
(
CDCl3 + CD OD, 300 MHz): 7.59 (d, J = 7.74 Hz, 1H,
N-((2S, 3R)-1-(Oleylamino)-1-oxo-3-((β-D-galactopyrano-
syl) oxy) butan-2-yl)-1H-indole-2-carboxamide (8f)
3
Ar–H), 7.35 (d, J = 7.93 Hz, 1H, Ar–H), 7.11–7.15 (m, 2H,
Ar–H), 7.03–7.05 (m, 1H, Ar–H), 5.33–5.39 (m, 2H,
HC=CH), 4.51 (d, J = 3.96 Hz, 1H, CH–NH), 4.26–4.28
1
Chloroform: methanol (95: 5, v/v), yield 70%. H-NMR
(
m, 1H, CH–OH), 4.04–4.08 (m, 1H, Gal-1), 3.81–3.87 (m
(CDCl3 + CD OD, 300 MHz): 7.66 (d, J = 7.93 Hz, 1H,
3
(
overlap), 3H, Gal-4 & 6), 3.67–3.72 (m, 1H, Gal-2),
.50–3.54 (m, 1H, Gal-3), 3.47–3.49 (m, 1H, Gal-5),
Ar–H), 7.46 (d, J = 8.49 Hz, 1H, Ar–H), 7.25–7.29 (m, 1H,
Ar–H), 7.17–7.20 (m, 1H, Ar–H), 7.09–7.14 (m, 1H,
Ar–H), 5.32–5.38 (m, 2H, HC=CH), 4.75–4.78 (m, 1H,
CH–NH), 4.62 (d, J = 4.34 Hz, 1H, CH–OH), 4.29 (d, J =
6.79 Hz, 1H, Gal-1), 4.16–4.20 (m, 1H, Gal-4), 3.87–3.92
(m, 1H, Gal-6), 3.72–3.81 (m (overlap), 2H, Gal-6 & 2),
3.51–3.61 (m (overlap), 1H, Gal-3 & 5), 3.15–3.28 (m, 2H,
H C–NH), 1.98–2.09 (m, 4H, H C–HC=CH), 1.54 (m, 2H,
3
3
6
.03–3.16 (m (overlap), 4H, H C–NH, CH ), 2.69 (t, J =
2
2
.98 Hz, 2H, CH ), 1.98–2.02 (m, 4H, H C–HC=CH), 1.26
2
2
(
m, 24H, CH ), 1.01 (d, J = 6.42 Hz, 3H, CHOH–CH ),
2
3
1
3
0
.88 (t, J = 6.98 Hz, 3H, CH3);
C-NMR (CDCl3
CD OD, 75 MHz): 174.5 (HN–C=O), 170.1 (HN–C=O),
+
3
1
36.8 (Ar–C–NH), 130.2 (H C–HC=CH), 130.1
2
2
2
(
(
H C–HC=CH), 127.4 (Ar–C–CH), 122.5 (Ar–CH), 121.8
Ar–CH), 119.1 (Ar–CH), 118.7 (Ar–CH), 113.9 (Ar–CH),
CH ), 1.26 (m, 25H, CH , CHOH–CH ), 0.88 (t, J = 6.42
2
2 2 3
1
3
Hz, 3H, CH3); C-NMR (CDCl3 + CD OD, 75 MHz):
3
1
2
3
11.6 (Ar–C), 102.2 (C-1), 75.8 (C-3), 74.5 (C-5), 73.8 (C-
), 71.5 (C-4), 69.4 (HC–OH), 62.1 (C-6), 57.5 (HC–NH),
170.5 (HN–C=O), 162.7 (HN–C=O), 137.7 (Ar–C–NH),
130.1 (O=C–C(NH)=CH, H C–HC=CH), 127.8 (Ar–C),
2
9.9
(O=C–NH–CH2),
36.9
(H C–C=O),
32.2
124.9 (Ar–CH), 122.3 (Ar–CH), 120.7 (Ar–CH), 112.4
(Ar–CH), 104.4 (Ar–CH), 99.4 (C-1), 75.6 (C-3), 73.9 (C-
5), 73.7 (C-2), 71.4 (C-4), 69.2 (HC–OH), 62.3 (C-6), 57.8
(HC–NH), 40.1 (O=C–NH–CH ), 32.9 (H C–HC=CH),
2
(
H C–HC=CH), 30 (O=C–NH–CH –CH ), 29.9 (CH ),
2 2 2 2
2
9.8 (CH ), 29.6 (CH ), 29.5 (CH ), 27.5 (CH ), 27.2
2 2 2 2
(
(
CH ), 22.9 (CH ), 21.5 (CH ), 15.9 (HOHC–CH ), 14.2
2 2 2 3
CH ); IR (KBr): 3395, 3042, 2922, 2862, 1629, 1540,
2
2
32.2 (O=C–NH–CH –CH ), 30.1 (CH ), 30 (CH ), 29.8
3
2 2 2 2
1
+
458, 1378, 1213, 1097, 924, 726; HRMS (ESI) m/z [M
H]-calc. for C H O N = 702.46879 found 702.46902.
(CH ), 29.6 (CH ), 27.5 (CH ), 27.3 (CH ), 23 (CH ), 16.8
2 2 2 2 2
(HOHC–CH ), 14.2 (CH ); IR (KBr): 3357, 3245, 2922,
3 3
3
9
64
8
3
2851, 1637, 1509, 1075, 721; HRMS (ESI) m/z [M+H]-
N-((2S, 3R)-1-(Oleylamino)-1-oxo-3-((β-D-galactopyrano-
syl) oxy) butan-2-yl)-1H-indazole-3-carboxamide (8e)
calc. for C H O N = 674.43749 found 674.43755.
3
7 60 8 3
(
2S, 3R)-N-(Oleyl)-2-(2-phenylacetamido)-3-((β-D-
1
Chloroform: methanol (95: 5, v/v), yield 68%. H-NMR
galactopyranosyl) oxy) butanamide (8g)
(
CDCl3 + CD OD, 400 MHz): 8.24 (d, J = 7.45 Hz, 1H,
3
1
Ar–H), 7.72 (d, J = 8.68 Hz, 1H, NH), 7.66 (t, J = 5.01 Hz,
Chloroform: methanol (95: 5, v/v), yield 72%. H-NMR
1
1
H, NH), 7.55 (d, J = 8.43 Hz, 1H, Ar–H), 7.39–7.43 (m,
H, Ar–H), 7.24–7.28 (m, 1H, Ar–H), 5.29–5.39 (m, 2H,
(CDCl3 + CD OD, 300 MHz): 7.26–7.32 (m, 5H, Ar–H),
3
5.33–5.39 (m, 2H, HC=CH), 4.46 (d, J = 3.02 Hz, 1H,
CH–NH), 4.33–4.35 (m, 1H, CH–OH), 4.16–4.20 (m, 1H,
Gal-1), 3.79–3.88 (m (overlap), 2H, Gal-4 & 6), 3.68–3.73
HC=CH), 4.78 (d, J = 4.64 Hz, 1H, CH–NH), 4.48–4.51
m, 1H, CH–OH), 4.32–4.35 (m, 1H, Gal-1), 3.97–4.02 (m,
(

Med Chem Res
(
2
m, 1H, Gal-6), 3.61 (s, 2H, CH ), 3.54–3.57 (m, 1H, Gal-
), 3.47–3.51 (m, 2H, Gal-3 & 5), 3.09–3.22 (m, 2H,
Ar–H), 6.83 (d, J = 8.52 Hz, 2H, Ar–H), 5.32–5.37 (m, 2H,
HC=CH), 5.11 (d, J = 3.57 Hz, 1H, NH), 4.60 (d, J = 4.12
Hz, 1H, NH), 4.47 (d, J = 3.30 Hz, 1H, CH–NH),
4.33–4.35 (m, 1H, CH–OH), 4.14–4.17 (m, 1H, Gal-1),
4.07–4.10 (m, 1H, Gal-4), 3.82–3.88 (m, 2H, Gal-6), 3.81
2
H C–NH), 1.96–2.05 (m, 4H, H C–HC=CH), 1.46 (m, 2H,
CH ), 1.27 (m, 22H, CH ), 1.13 (d, J = 6.42 Hz, 3H,
CHOH–CH ), 0.88 (t, J = 6.23 Hz, 3H, CH ); C-NMR
2
2
2
2
1
3
3
3
(
CDCl3 + CD OD, 75 MHz): 171.8 (HN–C=O), 169 (HN–
(s, 3H, Ar–OCH ), 3.67–3.74 (m, 1H, Gal-2), 3.53–3.57
3
3
C=O), 134.5 (Ar–C–CH ), 130 (H C–HC=CH), 129.5
(m, 1H, Gal-3), 3.49–3.51 (m, 1H, Gal-5), 3.13–3.29 (m,
2H, H C–NH), 2.59 (t, J = 7.42 Hz, 2H, CH ), 2.28 (t, J =
2
2
(
H C–HC=CH), 129.4 (Ar–CH), 128.7 (Ar–CH), 128.4
2
2
2
(
Ar–CH), 126.7 (Ar–CH), 101.8 (C-1), 75.1 (C-3), 73.9 (C-
7.42 Hz, 2H, CH2), 1.87–2.02 (m, 6H, CH2,
5
), 73.1 (C-2), 70.8 (C-4), 68.7 (HC–OH), 61.4 (C-6), 56.7
H C–HC=CH), 1.51 (m, 2H, CH ), 1.26 (m, 22H), 1.16 (d,
2
2
(
3
HC–NH), 42.7 (Ar–CH –C=O), 39.3 (O=C–NH–CH ),
J = 6.60 Hz, 3H, CHOH–CH ), 0.88 (t, J = 6.32 Hz, 3H,
3
2
2
1
3
2.2 (O=C–NH–CH –CH ), 31.5 (H C–HC=CH), 29.3
CH3); C-NMR (CDCl3 + CD OD, 75 MHz): 173.7 (HN–
2
2
2
3
(
CH ), 28.9 (CH ), 28.7 (CH ), 26.8 (CH ), 26.5 (CH ),
C=O), 169.2 (HN–C=O), 157.5 (Ar–C–OCH ), 133.3 (Ar–
2
2
2
2
2
3
2
3
1
=
2.3 (CH ), 15.2 (HOHC–CH ), 13.6 (CH ); IR (KBr):
354, 3063, 2924, 2853, 1730, 1637, 1513, 1466, 1287,
C–CH ), 129 (H C–HC=CH, Ar–CH), 113.5 (Ar–CH),
2
3
3
2
2
101.9 (C-1), 75.2 (C-3), 74.2 (C-5), 73.4 (C-2), 71(C-4),
68.8 (HC–OH), 61.6 (C-6), 56.6 (HC–NH), 54.9 (Ar–C–
O–CH3), 39.3 (H C–CH –C=O), 35.2 (O=C–NH–
074, 719; HRMS (ESI) m/z [M+H]-calc. for C H O N
3
6
61
8
2
649.44224 found 649.44309.
2
2
CH2), 34 (Ar–C–CH2), 32.3 (H C–HC=CH), 31.6
2
(
O=C–NH–CH –CH ), 29.3 (CH ), 29.2 (CH ), 29 (CH ),
2 2 2 2 2
(
(
2S, 3R)-2-(2-(4-Methoxyphenyl) acetamido)-N-(oleyl)-3-
(β-D-galactopyranosyl) oxy) butanamide (8h)
27.1 (CH ), 26.9 (CH ), 26.6 (CH ), 22.3 (CH ), 15.3
2 2 2 2
(HOHC–CH ), 13.7 (CH ); IR (KBr): 3284, 3081, 2924,
3
3
2
853, 1626, 1548, 1517, 1346, 1112. 973, 721; HRMS
1
Chloroform: methanol (95: 5, v/v), yield 68%. H-NMR
(ESI) m/z [M+H]-calc. for C H O N = 707.48411 found
3
9 67 9 2
(
CDCl3 + CD OD, 500 MHz): 7.51 (br s, 1H, NH),
707.48494.
3
7.22–7.25 (m, 2H, Ar–H), 6.86–6.89 (m, 2H, Ar–H),
5.33–5.38 (m, 2H, HC=CH), 4.52–4.54 (m, 1H, CH–NH),
4.33–436 (m, 1H, CH–OH), 4.17–4.20 (m, 1H, Gal-1),
3.86–3.87 (m, 1H, Gal-4), 3.82–3.84 (m, 2H, Gal-6), 3.81
N-((2S, 3R)-1-(Oleylamino)-1-oxo-3-((β-D-galactopyrano-
syl) oxy) butan-2-yl) hexanamide (8j)
(
(
s, 3H, Ar–OCH ), 3.71–3.74 (m, 1H, Gal-2), 3.54–3.57
m, 1H, Gal-3), 3.50–3.52 (m, 1H, Gal-5), 3.38 (s, 2H,
3
1
Chloroform: methanol (95: 5, v/v), yield 74%. H-NMR
CH ), 3.11–3.22 (m, 2H, H C–NH), 1.97–2.03 (m, 4H,
(CDCl3 + CD OD, 300 MHz): 7.42 (t, J = 5.77 Hz, 1H,
2
2
3
H C–HC=CH), 1.48 (m, 2H, CH ), 1.28–1.29 (m, 22H,
NH), 7.37 (d, J = 7.7 Hz, 1H, NH), 5.29–5.44 (m, 2H,
HC=CH), 4.59 (d, J = 4.4 Hz, 1H, CH–NH), 4.38 (m, 1H,
CH–OH), 4.16–4.20 (m, 1H, Gal-1), 3.88 (m, 1H, Gal-4),
3.84 (d, J = 7.7 Hz, 1H, Gal-6), 3.71 (dd, J = 3.85, 11.82
Hz, 1H, Gal-6), 3.54–3.57 (m, 1H, Gal-2), 3.51 (m (over-
2
2
CH ), 1.15 (d, J = 5.95 Hz, 3H, CHOH–CH ), 0.89 (t, J =
2
3
1
3
6
.56 Hz, 3H, CH3); C-NMR (CDCl3 + CD OD, 75 MHz):
3
1
73.3 (HN–C=O), 170.2 (HN–C=O), 159.3 (Ar–
C–OCH ), 130.7 (Ar–C–CH ), 130.4 (H C–HC=CH),
3
2
2
1
1
6
30.2 (H C–HC=CH), 127.5 (Ar–CH), 114.6 (Ar–CH),
02.8 (C-1), 76.1 (C-3), 74.9 (C-5), 74 (C-2), 71.7 (C-4),
9.6 (HC–OH), 62.3 (C-6), 57.8 (HC–NH), 55.5 (Ar–C–O–
lap), 2H, Gal-3 & 5), 3.14–3.29 (m, 2H, H C–NH), 2.27 (t,
2
2
J = 7.42 Hz, 2H, O=C–CH ), 2.02 (m, 4H, H C–HC=CH),
2
2
1.64 (m, 2H, CH ), 1.51 (m, 2H, CH ), 1.26–1.30 (m, 26H,
2 2
CH ), 42.6 (Ar–CH –C=O), 40.1 (O=C–NH–CH ), 32.4
CH ), 1.17 (d, J = 6.32 Hz, 3H, CHOH–CH ), 0.89 (t, J =
2 3
3
2
2
1
3
(
H C–HC=CH), 30.2 (O=C–NH–CH –CH ), 30 (CH ),
6.6 Hz, 6H, CH3); C-NMR (CDCl3 + CD OD, 75 MHz):
2
2
2
2
3
2
9.7 (CH ), 29.6 (CH ), 27.6 (CH ), 27.4 (CH ), 23.1
174.1 (HN–C=O), 169.3 (HN–C=O), 129.6 (H C–
2
2
2
2
2
(
CH ), 16.1 (HOHC–CH ), 14.3 (CH ); IR (KBr): 3292,
HC=CH), 129.4 (H C–HC=CH), 101.9 (C-1), 75.1 (C-3),
2
3
3
2
3
7
6
099, 2924, 2853, 1631, 1551, 1512, 1375, 1245, 1040,
74.1 (C-5), 73.1 (C-2), 70.9 (C-4), 68.8 (HC–OH), 61.5 (C-
53; HRMS (ESI) m/z [M+H]-calc. for C H O N =
6), 56.6 (HC–NH), 39.4 (O=C–NH–CH ), 35.8 (O=C–
3
7
63
9
2
2
79.45281 found 679.45298.
CH ), 32.2 (H C–HC=CH), 31.5 (O=C–CH –CH ), 31
2
2
2
2
(
CH ), 29.4 (CH ), 29.3 (CH ), 29.1 (CH ), 28.9 (CH ),
2 2 2 2 2
2
6.8 (CH ), 26.6 (CH ), 25 (CH ), 22.3 (CH ), 22 (CH ),
2 2 2 2 2
(
(
2S, 3R)-2-(4-(4-Methoxyphenyl) butanamido)-N-(oleyl)-3-
(β-D-galactopyranosyl) oxy) butanamide (8i)
16 (HOHC–CH ), 13.6 (CH ), 13.4 (CH ); IR (KBr): 3365,
3 3 3
2936, 2845, 1649, 1558, 1461, 1378, 1078, 716; HRMS
(
ESI) m/z [M+H]-calc. for C H O N = 629.47354 found
34 65 8 2
1
Chloroform: methanol (95: 5, v/v), yield 70%. H-NMR
629.47364.
(
CDCl3 + CD OD, 300 MHz): 7.10 (d, J = 8.52 Hz, 2H,
3

Med Chem Res
N-((2S, 3R)-1-(Oleylamino)-1-oxo-3-((β-D-galactopyrano-
syl) oxy) butan-2-yl) octanamide (8k)
N-((2S, 3R)-1-(Oleylamino)-1-oxo-3-((β-D-galactopyrano-
syl) oxy) butan-2-yl) undec-10-enamide (8m)
1
1
Chloroform: methanol (95: 5, v/v), yield 72%. H-NMR
Chloroform: methanol (95: 5, v/v), yield 75%. H-NMR
(
CDCl3 + CD OD, 500 MHz): 7.51 (br s, 1H, NH),
(CDCl3 + CD OD, 300 MHz): 5.73–5.87 (m, 1H,=CH),
3
3
5
(
3
.30–5.37 (m, 2H, HC=CH), 4.55 (m, 1H, CH–NH), 4.34
m, 1H, CH–OH), 4.19 (m, 1H, Gal-1), 3.86 (m, 1H, Gal-4),
.83 (d, J = 7.32 Hz, 1H, Gal-6), 3.71 (dd, J = 4.12, 11.74
5.29–5.42 (m, 2H, HC=CH), 4.9–5.01 (m, 2H,=CH ), 4.59
2
(d, J = 4.15 Hz, 1H, CH–NH), 4.35 (t, J = 3.58 Hz, 1H,
CH–OH), 4.17–4.20 (m, 1H, Gal-1), 3.86 (m, 1H, Gal-4),
3.83 (d, J = 7.36 Hz, 1H, Gal-6), 3.70 (dd, J = 3.96, 11.7
Hz, 1H, Gal-6), 3.53–3.57 (m, 1H, Gal-2), 3.50 (m, 2H,
Hz, 1H, Gal-6), 3.55 (m, 1H, Gal-2), 3.5 (m (overlap), 2H,
Gal-3 & 5), 3.14–3.27 (m, 2H, H C–NH), 2.28 (t, J = 7.47
2
Hz, 2H, O=C–CH ), 2.02 (m, 4H, H C–HC=CH), 1.63 (m,
Gal-3 & 5), 3.13–3.27 (m, 2H, H C–NH), 2.27 (t, J = 7.36
2
2
2
2
1
6
H, CH ), 1.51 (m, 2H, CH ), 1.27–1.31 (m, 30H, CH ),
Hz, 2H, O=C–CH ), 2.02 (m, 6H, H C–HC=CH,
2
2
2
2
2
.19 (d, J = 6.25 Hz, 3H, CHOH–CH ), 0.88 (t, J = 6.1 Hz,
H C–HC=CH ), 1.62 (m, 1H, CH ), 1.51 (m, 1H, CH ),
3
2 2 2 2
1
3
H, CH3); C-NMR (CDCl3 + CD OD, 75 MHz): 174
1.26–1.30 (m, 32H, CH ), 1.17 (d, J = 6.32 Hz, 3H,
2
3
1
3
(
(
(
(
(
(
2
HN–C=O), 169.4 (HN–C=O), 129.1 (H C–HC=CH), 129
H C–HC=CH), 101.4 (C-1), 74.9 (C-3), 73.7 (C-5), 72.9
C-2), 70.5 (C-4), 68.4 (HC–OH), 61.1 (C-6), 56.7
HC–NH), 38.9 (O=C–NH–CH ), 35.4 (O=C–CH ), 31.8
H C–HC=CH), 31.2 (O=C–CH –CH ), 31 (CH ), 29
CH ), 28.8 (CH ), 28.6 (CH ), 28.3 (CH ), 26.4 (CH ),
6.2 (CH ), 25 (CH ), 21.9 (CH ), 15.1 (HOHC–CH ), 13.1
CHOH–CH ), 0.88 (t, J = 6.23 Hz, 3H, CH ); C-NMR
2
3
3
(CDCl3 + CD OD, 75 MHz): 174.1 (HN–C=O), 169.3
2
3
(HN–C=O), 138.7 (H C–HC=CH), 129.5 (H C–HC=CH),
2
2
129.4 (H C–HC=CH), 113.7 (H C–HC=CH), 101.8 (C-1),
2
2
2
2
75.1 (C-3), 74 (C-5), 73.1 (C-2), 70.8 (C-4), 68.7
(HC–OH), 61.4 (C-6), 56.6 (HC–NH), 39.3 (O=C–NH–
CH ), 35.8 (O=C–CH ), 33.4 (H C–HC=CH), 32.2
2
2
2
2
2
2
2
2
2
2
2
2
3
2
2
2
(
CH ); IR (KBr): 3286, 2926, 2855, 1639, 1555, 1377,
(H C–HC=CH), 31.5 (O=C–CH –CH ), 29.4 (CH ), 29.3
3
2 2 2 2
1
078, 716; HRMS (ESI) m/z [M+H]-calc. for C H O N
(CH ), 29.1 (CH ), 28.9 (CH ), 28.7 (CH ), 28.5 (CH ),
2 2 2 2 2
3
6
69
8
2
=
657.50484 found 657.50486.
26.8 (CH ), 26.6 (CH ), 25.3 (CH ), 22.3 (CH ), 15.3
2 2 2 2
(
HOHC–CH ), 13.6 (CH ); IR (KBr): 3283, 2924, 2853,
3 3
1639, 1554, 1377, 1165, 1053, 719; HRMS (ESI) m/z [M
N-((2S, 3R)-1-(Oleylamino)-1-oxo-3-((β-D-galacto-
+H]-calc. for C H O N = 697.53614 found 697.53695.
39 73 8 2
pyranosyl) oxy) butan-2-yl)-2-propylpentanamide (8l)
1
Chloroform: methanol (95: 5, v/v), yield 71%. H-NMR
N-((2S, 3R)-1-(Oleylamino)-1-oxo-3-((β-D-galactopyrano-
syl) oxy) butan-2-yl) undecanamide (8n)
(
CDCl3 + CD OD, 300 MHz): 7.43 (d, J = 7.42 Hz, 1H,
3
NH), 7.34 (t, J = 5.5 Hz, 1H, NH), 5.29–5.39 (m, 2H,
HC=CH), 4.6 (m, 1H, CH–NH), 4.36 (m, 1H, CH–OH),
1
Chloroform: methanol (95: 5, v/v), yield 69%. H-NMR
4
7
.20 (m, 1H, Gal-1), 3.86 (m, 1H, Gal-4), 3.84 (d, J =
.42 Hz, 1H, Gal-6), 3.71 (dd, J = 4.12, 11.82 Hz, 1H,
(CDCl3 + CD OD, 300 MHz): 5.29–5.39 (m, 2H, HC=CH),
3
4.59 (d, J = 3.85 Hz, 1H, CH–NH), 4.48 (m, 1H, CH–OH),
4.19 (dd, J = 6.32, 10.72 Hz, 1H, Gal-1), 3.88 (d, J = 7.7 Hz,
1H, Gal-4), 3.84 (m, 1H, Gal-6), 3.70 (dd, J = 3.85, 11.82
Hz, 1H, Gal-6), 3.51–3.55 (m, 1H, Gal-2), 3.50 (m, 2H, Gal-3
Gal-6), 3.56 (m, 1H, Gal-2), 3.50 (m, 2H, Gal-3 5),
3
2
.13–3.29 (m, 2H, H C–NH), 2.27 (m, 1H, O=C–CH ),
2
2
.02 (m, 4H, H C–HC=CH), 1.46–1.62 (m, 8H, CH ),
2 2
1
.26–1.30 (m, 26H, CH ), 1.18 (d, J = 6.32 Hz, 3H,
& 5), 3.16–3.25 (m, 2H, H C–NH), 2.27 (t, J = 7.42 Hz, 2H,
2
2
1
3
CHOH–CH ), 0.86–0.93 (m, 9H, CH );
C-NMR
O=C–CH ), 1.98–2.02 (m, 4H, H C–HC=CH), 1.63 (m, 2H,
3
3
2
2
(
(
(
CDCl3 + CD OD, 75 MHz): 176.8 (HN–C=O), 169.3
CH ), 1.51 (m, 2H, CH ), 1.26–1.29 (m, 36H, CH ), 1.17 (d,
3
2 2 2
HN–C=O),
129.3
(H C–HC=CH),
129.1
J = 6.32 Hz, 3H, CHOH–CH ), 0.88 (t, J = 6.05 Hz, 6H,
3
2
1
3
H C–HC=CH), 101.6 (C-1), 75 (C-3), 73.7 (C-5), 73 (C-
2
CH3); C-NMR (CDCl3 + CD OD, 75 MHz): 174.1(HN–
3
2
4
), 70.6 (C-4), 68.5 (HC–OH), 61.2 (C-6), 56.5 (HC–NH),
C=O), 169.4 (HN–C=O), 129.4 (H C–HC=CH), 129.2
2
6.4 (O=C–CH), 39 (O=C–NH–CH ), 34.6 (O=C–CH–
(H C–HC=CH), 101.6 (C-1), 75 (C-3), 73.9 (C-5), 73 (C-2),
2
2
CH ), 31.3 (H C–HC=CH), 31.9 (CH ), 29.1 (CH ), 29
70.7 (C-4), 68.6 (HC–OH), 61.3 (C-6), 56.7 (HC–NH), 39.2
2
2
2
2
(
CH ), 28.9 (CH ), 28.7 (CH ), 26.5 (CH ), 26.3 (CH ),
(O=C–NH–CH ), 35.7 (O=C–CH ), 32.07 (H C–HC=CH),
2 2 2 2 2
2
2
2
2
2 (CH ), 20.1 (CH ), 15.1 (HOHC–CH ), 13.2 (CH ); IR
31.4 (O=C–CH –CH ), 29.3 (CH ), 29.2 (CH ), 29.1 (CH ),
2 2 2 2 2
2
2
3
3
(
KBr): 3483, 2925, 2867, 1632, 1556, 1462, 1093, 713;
29 (CH ), 28.8 (CH ), 26.7 (CH ), 26.4 (CH ), 25.2 (CH ),
2 2 2 2 2
HRMS (ESI) m/z [M+H]-calc. for C H O N =
22.1 (CH ), 15.2 (HOHC–CH ), 13.4 (CH ); IR (KBr): 3296,
3
6
69
8
2
2
3
3
6
57.50484 found 657.50509.
2924, 2846, 1656, 1526, 1377, 1232, 1165, 1043, 719;

Med Chem Res
HRMS (ESI) m/z [M+H]-calc. for C H O N = 699.55179
found 699.55217.
1648, 1553, 1368, 1163, 1077, 720; HRMS (ESI) m/z [M
+H]-calc. for C H O N = 741.59874 found 741.59940.
3
9 75 8 2
4
2 81 8 2
N-((2S, 3R)-1-(Oleylamino)-1-oxo-3-((β-D-
N-((2S, 3R)-1-(Oleylamino)-1-oxo-3-((β-D-
galactopyranosyl) oxy) butan-2-yl) hexadecanamide (8q)
galactopyranosyl) oxy) butan-2-yl) dodecanamide (8o)
1
Chloroform: methanol (95: 5, v/v), yield 71%. H-NMR
1
Chloroform: methanol (95: 5, v/v), yield 67%. H-NMR
(CDCl3 + CD OD, 300 MHz): 5.29–5.39 (m, 2H, HC=CH),
3
(
5
CDCl3 + CD OD, 300 MHz): 7.4 (t, J = 5.5 Hz, 1H, NH),
.29–5.39 (m, 2H, HC=CH), 4.59 (d, J = 3.85 Hz, 1H,
4.57 (d, J = 4.15, Hz, 1H, CH–NH), 4.34 (t, J = 3.77 Hz,
1H, CH–OH), 4.21 (dd, J = 5.85, 10.38 Hz, 1H, Gal-1),
3.85 (m, 1H, Gal-4), 3.83 (d, J = 7.17 Hz, 1H, Gal-6), 3.71
(dd, J = 4.15, 11.7 Hz, 1H, Gal-6), 3.53–3.57 (m, 1H, Gal-
3
CH–NH), 4.36 (m, 1H, CH–OH), 4.19 (dd, J = 6.32, 10.72
Hz, 1H, Gal-1), 3.86–3.88 (m, 1H, Gal-4), 3.84 (d, J = 7.42
Hz, 1H, Gal-6), 3.70 (dd, J = 4.12, 11.82 Hz, 1H, Gal-6),
2), 3.51 (m, 2H, Gal-3 & 5), 3.16–3.27 (m, 2H, H C–NH),
2
3
.53–3.57 (m, 1H, Gal-2), 3.51 (m, 2H, Gal-3 & 5),
2.28 (t, J = 7.36 Hz, 2H, O=C–CH ), 2.02 (m, 4H,
2
3
.16–3.27 (m, 2H, H C–NH), 2.27 (t, J = 7.42 Hz, 2H, O =
H C–HC=CH), 1.63 (m, 2H, CH ), 1.51 (m, 2H, CH ),
2
2
2
2
C–CH ), 2.02 (m, 4H, H C–HC = CH), 1.63 (m, 2H, CH ),
1.26–1.30 (m, 46H, CH ), 1.18 (d, J = 6.42 Hz, 3H,
CHOH–CH ), 0.88 (t, J = 6.23 Hz, 6H, CH ); C-NMR
3 3
2
2
2
2
1
3
1
.51 (m, 2H, CH ), 1.26–1.29 (m, 38H, CH ), 1.17 (d, J =
2
2
6
.32 Hz, 3H, CHOH–CH ), 0.88 (t, J = 6.05 Hz, 6H, CH );
(CDCl3 + CD OD, 75 MHz): 174.1 (HN–C=O), 169.4
3
3
3
1
3
C-NMR (CDCl3 + CD OD, 75 MHz): 174.1 (HN–C=O),
(HN–C=O), 129.4 (H C–HC=CH), 129.3 (H C–HC=CH),
3
2
2
1
69.3 (HN–C=O), 129.3 (H C–HC=CH), 129.2
101.7 (C-1), 75.1 (C-3), 73.9 (C-5), 73.1 (C-2), 70.8 (C-4),
68.6 (HC–OH), 61.3 (C-6), 56.7 (HC–NH), 39.2
(O=C–NH–CH ), 35.8 (O=C–CH ), 32.1 (H C–HC=CH),
2
(
H C–HC=CH), 101.6 (C-1), 75 (C-3), 73.9 (C-5), 73 (C-
2
2
3
), 70.7 (C-4), 68.6 (HC–OH), 61.3 (C-6), 56.6 (HC–NH),
9.1 (O=C–NH–CH2), 35.7 (O=C–CH2), 32
2
2
2
31.4(O=C–CH –CH ), 29.2 (CH ), 29 (CH ), 28.8 (CH ),
2
2
2
2
2
(
H C–HC=CH), 31.4 (O=C–CH –CH ), 29.1 (CH ), 29
26.7 (CH ), 26.5 (CH ), 25.3 (CH ), 22.2 (CH ), 15.3
2
2
2
2
2 2 2 2
(
CH ), 28.8 (CH ), 26.6 (CH ), 26.4 (CH ), 25.2 (CH ),
(HOHC–CH ), 13.4 (CH ); IR (KBr): 3386, 2923, 2852,
3 3
2
2
2
2
2
2
3
2.1 (CH ), 15.2 (HOHC–CH ), 13.3 (CH ); IR (KBr):
283, 2924, 2853, 1639, 1554, 1232, 1165, 1053, 719;
1638, 1546, 1379, 1163, 1088, 720; HRMS (ESI) m/z [M
+H]-calc. for C H O N = 769.63004 found 769.63034.
2
3
3
4
4 85 8 2
HRMS (ESI) m/z [M+H]-calc. for C H O N =
4
0 77 8 2
7
13.56744 found 713.56740.
N-((2S, 3R)-1-(Oleylamino)-1-oxo-3-((β-D-
galactopyranosyl) oxy) butan-2-yl) octadecanamide (8r)
1
N-((2S, 3R)-1-(Oleylamino)-1-oxo-3-((β-D-
Chloroform: methanol (95: 5, v/v), yield 72%. H-NMR
galactopyranosyl) oxy) butan-2-yl) tetradecanamide (8p)
(CDCl3 + CD OD, 300 MHz): 7.46 (t, J = 6.05 Hz, 1H,
3
NH), 5.29–5.38 (m, 2H, HC=CH), 4.57 (d, J = 4.12 Hz,
1H, CH–NH), 4.34 (t, J = 3.57, 1H, CH–OH), 4.21 (dd, J
= 5.77, 11.82 Hz, 1H, Gal-1), 3.88 (m, 1H, Gal-4), 3.83 (m,
1H, Gal-6), 3.71 (dd, J = 3.85, 11.55 Hz, 1H, Gal-6),
3.53–3.57 (m, 1H, Gal-4), 3.51 (m, 2H, Gal-3 & 5),
1
Chloroform: methanol (95: 5, v/v), yield 70%. H-NMR
(
CDCl3 + CD OD, 300 MHz): 5.30–5.38 (m, 2H, HC=CH),
3
4
1
3
.60 (d, J = 4.15 Hz, 1H, CH–NH), 4.36 (t, J = 3.58 Hz,
H, CH–OH), 4.18 (dd, J = 6.42, 10.95 Hz, 1H, Gal-1),
.87 (m, 1H, Gal-4), 3.83 (d, J = 7.17 Hz, 1H, Gal-6), 3.71
3.15–3.27 (m, 2H, H C–NH), 2.28 (t, J = 7.15 Hz, 2H,
2
(
dd, J = 3.96, 11.89 Hz, 1H, Gal-6), 3.54–3.58 (m, 1H, Gal-
O=C–CH ), 2.02 (m, 4H, H C–HC=CH), 1.63 (m, 2H,
2
2
2
), 3.51 (m, 2H, Gal-3 & 5), 3.14–3.25 (m, 2H, H C–NH),
CH ), 1.51 (m, 2H, CH ), 1.26–1.31 (m, 50H, CH ), 1.18
2
2 2 2
2
.26 (t, J = 7.36 Hz, 2H, O=C–CH ), 2.02 (m, 4H,
(d, J = 6.32 Hz, 3H, CHOH–CH ), 0.88 (t, J = 5.77 Hz, 6H,
3
2
1
3
H C–HC=CH), 1.62 (m, 2H, CH ), 1.51 (m, 2H, CH ),
CH3); C-NMR (CDCl3 + CD OD, 75 MHz): 174.1 (HN–
2
2
2
3
1
.26 (m, 42H, CH ), 1.16 (d, J = 6.42 Hz, 3H, CHOH–
C=O), 169.3 (HN–C=O), 129.5 (H C–HC=CH), 129.3
2
2
1
3
CH ), 0.88 (t, J = 6.23 Hz, 6H, CH ); C-NMR (CDCl3
(H C–HC=CH), 101.8 (C-1), 75.1 (C-3), 74 (C-5), 73.1 (C-
3
3
2
CD OD, 75 MHz): 174.1 (HN–C=O), 169.3 (HN–C=O),
2), 70.9 (C-4), 68.7 (HC–OH), 61.5 (C-6), 56.7 (HC–NH),
+
3
1
7
29.5 (H C–HC=CH), 129.3 (H C–HC=CH), 101.7 (C-1),
5.1 (C-3), 74 (C-5), 73.1 (C-2), 70.8 (C-4), 68.7
39.2
(O=C–NH–CH2),
35.8
(O=C–CH2),
31.5
2
2
(H C–HC=CH), 29.3 (O=C–CH –CH ), 29.1 (CH ), 28.9
2
2
2
2
(
HC–OH), 61.4 (C-6), 56.6 (HC–NH), 39.3 (O=C–NH–
(CH ), 26.8 (CH ), 26.5 (CH ), 25.3 (CH ), 22.2 (CH ),
2 2 2 2 2
CH ), 35.8 (O=C–CH ), 32.2 (H C–HC=CH), 31.5
15.3 (HOHC–CH ), 13.5 (CH ); IR (KBr): 3286, 2923,
2
2
2
3
3
(
O=C–CH –CH ), 29.2 (CH ), 29.1 (CH ), 28.9 (CH ),
2852, 1638, 1553, 1379, 1163, 1077, 720; HRMS (ESI) m/z
2
2
2
2
2
2
6.8 (CH ), 26.5 (CH ), 25.3 (CH ), 22.2 (CH ), 15.3
[M+H]-calc.
for
C H O N = 797.66134
46 89 8 2
found
2
2
2
2
(
HOHC–CH ), 13.6 (CH ); IR (KBr): 3286, 2932, 2854,
797.66175.
3
3

Med Chem Res
N-((2S, 3R)-1-(Oleylamino)-1-oxo-3-((β-D-
galactopyranosyl) oxy) butan-2-yl) oleamide (8s)
HTB-22), HeLa: human cervical cancer cell line (ATCC
No. CCL-2) and HEK 293: normal human embryonic kid-
ney cells (ATCC No. CRL-1573) using the MTT assay
(Mosmann 1983). The IC50 values (50% inhibitory con-
centration) were calculated from the plotted absorbance data
for the dose response curves. IC50 values (in µM) are
expressed as the average of two independent experiments.
1
Chloroform: methanol (95: 5, v/v), yield 72%. H-NMR
CDCl3 + CD OD, 300 MHz): 5.32–539 (m, 4H, HC=CH),
(
3
4
.56 (d, J = 4.40 Hz, 1H, CH–NH), 4.48–4.49 (m, 1H,
CH–OH), 4.32–4.35 (m, 1H, Gal-1), 4.18–4.22 (m, 1H,
Gal-4), 3.81–3.90 (m, 2H, Gal-6), 3.68–3.74 (m, 1H, Gal-
2
3
), 3.53–3.57 (m, 1H, Gal-3), 3.50–3.51 (m, 1H, Gal-5),
.14–3.28 (m, 2H, H C–NH), 2.28 (t, J = 7.42 Hz, 2H,
2
Results and discussion
O=C–CH ), 1.90–2.11 (m, 8H, H C–HC=CH), 1.64 (m,
2
2
2
H, CH ), 1.52 (m, 2H, CH ), 1.27–1.31 (m, 42H, CH ),
2 2 2
Synthesis and characterization
1
.18 (d, J = 6.32 Hz, 3H, CHOH–CH ), 0.88 (t, J = 6.32
3
1
3
Hz, 6H, CH3); C-NMR (CDCl3 + CD OD, 75 MHz): 175
3
New class of threonine-based β-galactosylceramides with
replacement of fatty-acyl group on amide moiety with dif-
ferent aromatic acids and various fatty-acyl moieties were
synthesized using the starting material L-threonine. As
shown in Scheme 1, L-threonine methyl ester hydrochloride
(1) was prepared from L-threonine using 2 M methanalic
HCl solution under reflux conditions. L-threonine methyl
ester hydrochloride (1) was further derivatized to afford N-
aromatic/fatty-acyl threonine methyl esters (2a–2s) with
different aromatic acids/fatty acids using EDC.HCl and
HOBt coupling reagents. This amide bond was further
(
1
7
(
(
HN–C=O), 170.4 (HN–C=O), 130.4 (H C–HC=CH),
2
30.1 (H C–HC=CH), 102.6 (C-1), 76 (C-3), 74.8 (C-5),
2
4 (C-2), 71.7 (C-4), 69.6 (HC–OH), 62.2 (C-6), 57.7
HC–NH), 40.1 (O=C–NH–CH ), 36.6 (O=C–CH ), 33.02
2 2
H C–HC=CH), 32.3 (H C–HC=CH), 30.2 (O=C–CH –
2
2
2
CH ), 30.1 (CH ), 29.9 (CH ), 29.7 (CH ), 27.6 (CH ), 27.4
(
(
2
2
2
2
2
CH ), 26.2 (CH ), 23.1 (CH ), 16.1 (HOHC–CH ), 14.3
2 2 2 3
CH ); IR (Neat): 3286, 2924, 2853, 1638, 1549, 1461,
3
1
146, 1077, 718; HRMS (ESI) m/z [M+H]-calc. for
C H O N = 795.64569 found 795.64547.
4
6 87 8 2
1
confirmed through H-NMR, where the N–H proton signals
In vitro cytotoxicity evaluation assay
appears as broad doublet/singlet at δ = 6.2–7.0 ppm range.
Further to obtain compounds 3a–3s, N-aromatic/fatty-acyl
threonine methyl esters 2a–2s were hydrolyzed with LiOH.
H O in THF (Tetrahydrofuran)-H O solvent mixture and
The cytotoxicity of the prepared threonine-based galacto-
ceramide derivatives were evaluated on the basis of mea-
surement of in vitro growth of tumor cell lines in 96-well
plates by cell mediated reduction of tetrazolium salt to water
insoluble formazan crystals using doxorubicin as a standard
control. The cytotoxicity was assessed against a panel of
three different tumor cell lines: A549: human alveolar
adenocarcinoma epithelial cells (ATCC No. CCL-185),
MCF-7: human breast adenocarcinoma cells (ATCC No.
2
2
this was followed by acidification of lithium salts with 2 N
1
HCl and these free acid compounds were identified by H-
NMR, the characteristic methyl group protons disappeared
at 3.7 ppm. This free acid compounds 3a–3s were further
derivatized with oleyl amine in presence of EDC.HCl and
HOBt coupling reagents to give the desired mixture of di-
amide compounds 4a–4s. Di-amide was confirmed by the
Scheme 1 Reagents and conditions: (i) HCl 2 M, MeOH, reflux, 2 h,
acetonyl (2g, 3g, 4g), 4-Methoxy phenylacetonyl (2h, 3h, 4h), 4-
Methoxy phenyl butanoyl (2i, 3i, 4i), Hexanoyl (2j, 3j, 4j), Octanoyl
(2k, 3k, 4k), 2-Propylpentanoyl (2l, 3l, 4l), Undecenoyl (2m, 3m, 4m),
Undecanoyl (2n, 3n, 4n), Dodecanoyl (2o, 3o, 4o), Tetradecanoyl (2p,
3p, 4p), Hexadecanoyl (2q, 3q, 4q), Octadecanoyl (2r, 3r, 4r), Oleoyl
(2s, 3s, 4s)
9
8%; (ii) Acid, EDC.HCl, HOBt, Dichloromethane (DCM), room
temperature (rt), Overnight, 78–84%; (iii) LiOH.H O, THF, H O, rt,
6 h, 88–95%; (iv) Oleyl amine, EDC.HCl, HOBt, DCM, rt, overnight,
5–80%. R = Cinnamoyl (2a, 3a, 4a), 4-Nitro cinnamoyl (2b, 3b, 4b),
2
2
1
7
Indole-3-acetanoyl (2c, 3c, 4c), Indole-3-propanoyl (2d, 3d, 4d),
Indazole-3-cabonyl (2e, 3e, 4e), Indole-2-cabonyl (2f, 3f, 4f), Phenyl

Med Chem Res
Scheme 2 Reagents and conditions: (i) NaOAc, Ac
2
O, reflux, 4 h,
3-propanoyl (8d), Indazole-3-cabonyl (8e), Indole-2-cabonyl (8f),
Phenyl acetonyl (8g), 4-Methoxy phenylacetonyl (8h), 4-Methoxy
phenyl butanoyl (8i), Hexanoyl (8j), Octanoyl (8k), 2-Propylpentanoyl
(8l), Undecenoyl (8m), Undecanoyl (8n), Dodecanoyl (8o), Tetra-
decanoyl (8p), Hexadecanoyl (8q), Octadecanoyl (8r), Oleoyl (8s)
9
2%; (ii) Benzyl amine, THF, room temperature (rt), 20 h, 84%; (iii)
3
CCl CN, DBU, DCM, rt, 2.5 h, 77%; (iv) 4(a–s), TMSOTf, DCM, rt,
1
2 h, NaOMe, MeOH, Amberlite-IR-120, rt, 1 h, 65–74%. R = Cin-
namoyl (8a), 4-Nitro cinnamoyl (8b), Indole-3-acetanoyl (8c), Indole-
presence of oleyl moiety double bond protons at δ =
In vitro cytotoxicity evaluation
5
.35–5.40 ppm as multiplet and one more N–H proton of
new amide bond appeared as a singlet at δ = 6.8–7.0 ppm in
Galactoceramides and its derivatives have gained much
attention from a cancer chemoprevention perspective due to
their promising inhibitory effect on tumor growth. Fatty-
acyl group on amide moiety or phytosphingosine group, and
chain length are some of the important features that influ-
ence the cytotoxicity. In this regard, all the synthesized
compounds were evaluated for cytotoxicity (Mosmann
1983) against three cancer cell lines such as human alveolar
adenocarcinoma epithelial cells (A549), human breast ade-
nocarcinoma cells (MCF-7), human cervical cancer cell line
(HeLa), and one normal cell line such as normal human
embryonic kidney cells (HEK-293) and the results to this
regard are tabulated in Table 1.
1
the H-NMR spectrum of the corresponding compounds.
1
All the compounds were fully characterized by H-NMR,
1
3
C-NMR, IR, and ESI–MS spectral analysis.
The mixture of di-amide compounds 4a–4s were glyco-
sylated by employing trichloroacetimidate methodology. As
depicted in the Scheme 2, 1,2,3,4,6-penta-O-acetyl-β-D-
galactopyranose (5) was prepared by our previous protocol
(
Vudhgiri et al. 2017). Further, the anomeric acetyl group
was chemoselectively deprotected by using benzyl amine
Manzo et al. 2012) and the formation of hemiacetal was
(
confirmed by the disappearance of one acetate group pro-
tons present at 2 ppm range in proton NMR spectrum.
The glycosyl donor α-trichloroacetimidate (7) was pre-
pared from hemiacetal (6) by using trichloroacetonitrile in
the presence of DBU at room temperature (Manzo et al.
Based on the results, all the tested compounds 8a–8s
exhibited moderate to good cytotoxicity against all the
tested cancer cell lines with IC50 values ranging between
14.08 to 64.05 µM. Among all the synthesized compounds,
aromatic-acid derivatives were more promising as compared
to fatty-acid derivatives because of the absence of additional
2
012). The imidate formation was confirmed through the
imine proton which appeared at δ = 8.6 ppm as singlet in
proton NMR spectrum. The coupling of imidate (7) was
carried out with di-amide compounds 4a–4s in presence of
TMSOTf for overnight at room temperature (Schmidt
ʹ
hydrogen bond on the wall of the A pocket in the CD1d
hydrophobic groove in fatty-acid derivatives as compared to
the aromatic-acid derivatives. These results corroborated
with the earlier reports (Fujio et al. 2006; Wu et al. 2006).
In addition, among all the tested aromatic derivatives,
compound 8i exhibited promising activity against MCF7,
A549, and HeLa cancer cell lines with IC50 values of 14.08,
14.78, and 16.70 µM, respectively. Further, the compounds
8f, 8g, 8h, and 8i showed promising activity against MCF7
cancer cell line with IC50 values of 15.49, 15.70, 15.43, and
14.08 µM, while compound 8e exhibited good activity
against HeLa cancer cell line with IC50 value of 16.78 µM.
Based on the cytotoxicity results for compounds 8h and 8i,
the cytotoxicity increases with an increase in the spacer
chain length between aromatic residue and amide functional
group. These results support an earlier report (Fujio et al.
2006). Based on the results for compounds 8g and 8h,
1
986). After completion of all the starting materials, the
reaction mixture was filtered and dissolved in chloroform.
The organic layer was extracted with aq. NaHCO solution,
3
dried over anhydrous Na SO and concentrated under
2
4
reduced pressure. This crude mixture was subjected to
Zemplen deacetylation (Zemplen and Kunz 1923) to pro-
duce compounds 8a–8s in β–configuration. This β-
′
orientation was achieved by NGP of C-2 acetate group of
sugar with C-1ʹ carbon of sugar as it allowed only equatorial
attack of acceptor. Further, β–configuration was confirmed
by the presence of anomeric carbon (for compounds 8a–8i
1
02 ppm range and for compounds 8j–8s 101 ppm range) as
1
3
single peak in C-NMR spectrum. These results further
corroborated with previously reported spectral data (Sjolin
et al. 1996).

Med Chem Res
Table 1 In vitro cytotoxicity
evaluation of different
Test compound
IC50 values (µM)
threonine-based galactoceramide
aromatic and fatty-acid
derivatives (8a–8s)
A549
MCF 7
HeLa
HEK 293
8a
27.82 ± 0.17
28.35 ± 0.21
64.05 ± 0.12
36.37 ± 0.92
18.35 ± 0.32
17.64 ± 0.02
19.59 ± 0.42
18.71 ± 0.32
14.78 ± 0.32
26.09 ± 0.18
27.58 ± 0.77
22.54 ± 0.17
20.66 ± 0.52
22.28 ± 0.31
22.75 ± 0.65
21.77 ± 0.77
23.02 ± 0.02
22.92 ± 0.96
25.91 ± 0.10
2.10 ± 0.09
21.62 ± 0.41
26.08 ± 0.91
49.62 ± 0.06
38.85 ± 0.41
19.19 ± 0.21
15.49 ± 0.81
15.70 ± 0.07
15.43 ± 0.91
14.08 ± 0.36
37.25 ± 0.43
34.67 ± 0.06
25.69 ± 0.06
19.78 ± 0.77
18.05 ± 0.42
20.37 ± 0.84
18.83 ± 0.91
21.36 ± 0.81
22.92 ± 0.51
22.18 ± 0.61
3.12 ± 0.12
26.20 ± 0.32
30.61 ± 0.29
61.07 ± 0.15
39.00 ± 0.08
16.78 ± 0.16
16.04 ± 0.36
18.17 ± 0.78
17.99 ± 0.26
16.70 ± 0.11
27.48 ± 0.76
24.50 ± 0.99
23.78 ± 0.12
16.34 ± 0.23
19.74 ± 0.06
20.11 ± 0.02
19.40 ± 0.21
24.40 ± 0.62
24.60 ± 0.99
22.70 ± 0.87
1.78 ± 0.24
96.23 ± 0.63
88.63 ± 0.56
91.26 ± 0.36
99.36 ± 0.49
74.26 ± 0.96
86.23 ± 0.65
92.34 ± 0.26
97.56 ± 0.13
88.16 ± 0.26
60.412 ± 0.23
64.69 ± 0.32
61.32 ± 0.36
98.26 ± 0.96
86.92 ± 0.59
73.69 ± 0.63
97.26 ± 0.34
84.26 ± 0.69
95.26 ± 0.54
84.26 ± 0.46
78.26 ± 0.89
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
Doxorubicin
A549: human alveolar adenocarcinoma epithelial cells (ATCC No. CCL-185), MCF-7: human breast
adenocarcinoma cells (ATCC No. HTB-22), HeLa: human cervical cancer cell line; HEK 293: human
embryonic kidney cells 293
methoxy group also influenced the cytotoxicity of the
compounds. The indazole derivative (8e) exhibited good
activity due to the presence of more nitrogen atoms as it
may provide additional hydrogen bond stability as dis-
cussed in an earlier report (Yogesh Kumar et al. 2016).
Furthermore, all the aromatic-acid derivatives showed good
to moderate cytotoxicity against all the tested cancer cell
lines.
considerable effect on cytotoxicity as compared to the
saturated fatty-acid derivative. Furthermore, all the fatty-
acid derivatives showed good to moderate cytotoxicity
against all the tested cancer cell lines.
Conclusions
In case of fatty-acid derivatives, compounds 8j–8s
exhibited good cytotoxicity against all the tested cancer cell
lines with IC50 values ranging between 16.34 to 37.25 µM.
The unusual undecenoic acid (8m), lauric acid (8o) and
undecanoic acid (8n), myristic acid (8p) derivatives
exhibited promising activity against HeLa and MCF7 can-
cer cell lines with IC50 values of 16.34, 20.11 and 18.05,
In the present study, the synthesis of threonine-based β-
galactoceramide was carried out and its derivatives were
prepared by modifying the fatty-acyl group on amide moi-
ety with different unusual, branched, saturated, and unsa-
turated fatty-acyl moieties and aromatic acids employing
trichloroacetimidate methodology. Further, all the synthe-
sized compounds were evaluated for in vitro cytotoxicity
and all these compounds exhibited good to moderate
cytotoxicity against all the tested cancer cell lines with IC50
values ranging between 14.08 to 64.05 µM. Among all the
compounds, the compounds 8i, 8m, and 8n exhibited pro-
mising cytotoxicity. Based on structure–activity relation-
ship, aromatic-acid derivatives exhibited promising activity
as compared to fatty-acid derivatives. Further, the com-
pounds bearing longer spacer chain length between aro-
matic residue and amide functional group, methoxy
1
8.33 µM, respectively. All these compounds exhibited
good cytotoxicity against the remaining cancer cell lines
with ≤ 20 µM. The results for the compounds 8k and 8l
demonstrated that the branched chain acid derivative (8l)
exhibited good cytotoxicity against all the tested cancer cell
lines as compared to straight chain fatty-acid derivative
(
(
8k). The results of same chain length terminal unsaturated
8m) and saturated (8n) fatty-acid derivatives revealed that
terminal unsaturated fatty-acid derivative showed

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