Article Type: Research Article Article Citation: Eugene L. Ayuk, Precious A. Afoke, Samuel B.
Aronimo, and Temitayo A. Olowolafe. (2020). SYNTHESIS AND PRELIMINARY MOLECULAR
DOCKING STUDIES OF NOVEL ETHYL-GLYCINATE AMIDE DERIVATIVES. International
Journal of Research -GRANTHAALAYAH, 8(9), 368-382. https://doi.org/10.29121/granthaalayah.v8.i9.2020.338 Received Date: 1 June 2020 Accepted Date: 30 September 2020 Keywords: Glycine Esterification Molecular Docking Celecoxib and Rofecoxib Inhibitory Activity Ethyl glycinate was synthesized by the Fischer esterification protocol, and its amide derivatives; 2-amino-N-(nitrophenyl)acetamide 31, 2-amino-N-(6-methylpyridin-2-yl) acetamide 33, N,N'-(1,4-phenylene)bis-(2-aminoacetamide) 35, N,N'-(6-chloropyrimidine-2,4-diyl)bis-(2-aminoacetamide) 37, and 2,4-(diamino-N’N-6-hydroxypyrimidyl)acetamide 39 respectively were obtained by coupling reactions of 4-nitroaniline, 2-amino-6-methylpyridine, 1,4-diamino-N,N’-benzene, 2,6-diamino-4-chloropyrimidine and 2,4-diamino-6-hydroxypyrimidine respectively with ethyl glycinate. These compounds were characterized on the basis of their melting points, UV-Visible, IR, 1HNMR and 13CNMR spectroscopic analyses. The results obtained from the spectra were consistence with the assigned structures of the compounds. The synthesized compounds were subjected to molecular docking with a target protein, 1CVU to compare their binding energies with celecoxib and rofecoxib which are standard drugs that inhibit COX2 enzyme. From the docking results, the binding energies values of the above synthesized compounds are -5.8 kJmol-1, -6.2 kJmol-1, -7.2 kJmol-1, -7.4 kJmol-1 and -7.6 kJmol-1 respectively. Compound 39 showed the highest binding energy of -7.6 kJmol-1, close to celecoxib and rofecoxib with binding energy values of -8.0 kJmol-1 and -8.2 kJmol-1 respectively. This result indicates that compound 39 possess some level of inhibitory activity against COX2.
1. INTRODUCTIONAmino acids are
molecules containing both amino and carboxylic acid groups. There are basically
twenty in number namely; glycine 1,
alanine 2, serine3, threonine 4, cysteine 5, valine6, leucine7, isoleucine 8,
methionine 9, proline10, phenylalanine 11, tyrosine 12,
tryptophan 13, aspartic acid 14, glutamic acid 15, asparagine 16,
glutamine 17, histidine18, lysine 19, arginine 20, and of
all these, glycine1 is the simplest,
Young (1994). Out
of these, nine of them are classified as essential amino acids, because they
cannot be synthesized by the body and are therefore required to be taken in
diets namely; histidine, leucine, isoleucine, lysine, methionine,
phenylalanine, threonine, tryptophan, and valine according to Dietary Reference
Intakes (2014). The non-essential amino acids can be synthesized in the body
and they include alanine, aspartic acid, asparagine, glutamic acid, serine,
while arginine, cysteine, glycine, glutamine, proline, and tyrosine are
classified as conditionally essential amino acids, meaning their synthesis can
be limited under special pathophysiological conditions, such as prematurity in
the infant or individuals in severe catabolic distress, Young (1994) and Dietary
Reference Intakes (2014). Amino acids are the
building blocks for protein synthesis, through the formation of peptides
linkages according to Wilson (2016). The structures of the twenty (20)
alpha-amino acids are shown in fig 1 below. Figure 1: Structures and names of the 20 amino acids Glycine 1 is the simplest and a conditionally
essential amino acid; its chemical formula is C2H5NO2.
It is a white solid with density of 1.607g/mol. It is soluble in pyridine,
sparingly soluble in ethanol and insoluble in ether. It was first produced by a
French chemist, H. Braconnot from acid hydrolysis of protein in 1820, according
to Wang et al (2013). It has a sweet
taste like glucose and can also be produced by alkaline hydrolysis of meat and
gelatin with potassium hydroxide. Because of its simplicity, it has only one
form, unlike other amino acids that possess the L and D isomers. Wu (2009) reported
that glycine supports healthy kidney and liver function as well as the nervous
system and serves as a major constituent in extracellular structural proteins
(collagen and elastin) in animals. Although glycine has been traditionally
classified as a ‘‘nutritionally conditionally essential amino acid’’ for
mammals (including humans, pigs and rodents) due to the presence of its
endogenous synthesis in the body according to Wu, (2010), and Darling et al.(1999), it has been reported that
the amount of glycine synthesized in vivo is insufficient to meet metabolic
demands in these species according to Jackson (1991), Melendez-Heviaet al. (2009), and Rezaeiet al., (2013). Other functions of
glycine include: protection of the body against hyper toxicity by effectively
and successively fighting against ethanol induced toxicity according to
Senthilkumar et al (2004), Zeb and
Rahman (2017), an effective therapy for shocks, Abello et al (1994), treatment of gastric ulcer by decreasing the acid
secretions caused by pylorus ligation, prevention of organ transplanting
failure (kidneys) when treated with a solution containing glycine and Carolina,
Zeb and Rahman (2017). This mixture helps to protect the kidneys against
storage injury as well as long survival after kidney transplantation Yin et al (2002). Glycine is a very
successful immunomodulatory that suppresses inflammation. It also prevents
aging in human system. Glycine could
also help in the correction of erectile dysfunction, enables proper circulation
of blood, helps in cholesterol reduction, prevention of diabetes, hair loss,
insomnia and menopause, boosting of the immune system, quickens surgery
recovery, improves fertility, it also helps in weight loss and well-being.
Shortage of glycine in small quantities is not harmful for health but severe
shortage may lead to failure of immune response, low growth, abnormal nutrient
metabolism as well as other undesirable effects on health, Lewis et al (2005). A typical example of a
glycine derivative that can bring about reduction of cholesterol level in the
body is dimethylglycine 21. Figure 2: Structure of dimethylglycine Esters are products
obtained from the reaction of carboxylic acids and alcohols with the
elimination of a water molecule by the process of esterification as shown in
the reaction scheme below IUPAC, “in the Gold Book (1997). Figure 3: Reaction scheme for esters synthesis Amides 26 on the other hand are compounds
derived from the reaction of a carboxylic acid and an amino compound where a
carboxylic acid group, and in an amide is replaced by the –NH of an NH2
group as shown below, Montalbetti and Falque (2005), Smith and March (2007). Figure 4: Reaction scheme for amides synthesis Amide derivatives
have been reported to possess broad spectrum of biological activities such as
antituberculosis, Mohamed et al (2007),
anticonvulsant, Nadeemet al (2008),
analgesic, anti-inflammatory, Galewicz-Walesa et al (2003), insecticidal, Graybillet al (1992), antifungal, Mihealaet al (2008), and antitumor properties, Andre et al (2007). Compounds containing amide functionalities have
proven to be potentially active against various fungal strains and many of them
have got wide acceptance in clinical trials according to Ledmicer and Mitschen
(1980); Delegado and Remars (2004). They are considered as pro-drugs,
biologically inactive compounds which can be metabolized in the body to produce
drug activity, Surrender et al (2010). Cyclooxygenase (COX)
officially known as prostaglandin-endoperoxide synthase
(PTGS) is an enzymethat is responsiblefor formation
of prostanoids, including thromboxane and prostaglandins such as prostacyclin,
from arachidonic acid, Kristina et al (2006). Various prostaglandin
synthases then convert PGH2 into several different prostaglandins
and thromboxanes, Liu et al (2006). These prostaglandins and thromboxanes
target specific G protein-coupled receptors and play major roles in regulation
of renal function, platelet aggregation, protection of the stomach lining, and
other numerous biological tasks, as well as mediation of the cellular
inflammatory response, Kristina et al (2006) and Liu
et al (2006). These functions are attributed mainly to the first of the two
established COX isoforms, the COX-1, while the inflammatory response is largely
associated with the inducible isoform, COX-2. Pharmaceutical inhibition of COX can provide relief from
the symptoms of inflammation and pain. Those that are specific to the COX-2 isozyme are called COX-2 inhibitors. For example the active metabolite (AM404) of paracetamol believed to provide most or all of its analgesic effects is a COX
inhibitor, and this is believed to provide part of its effect, Liu et al (2006)
and Högestätt et al (2005).
Inhibition of COX-2 produces the analgesic, antipyretic, and anti-inflammatory
effects typical of non-steroidal anti-inflammatory drugs (NSAIDs), while
inhibition of COX-1 is responsible for the antithrombotic effects of aspirin
and other nonselective NSAIDs, as well as many of their side effects, such as
gastric ulcer formation. The many therapeutically useful effects of COX
inhibition have made the NSAIDs among the most widely used drugs of the past
century according to Högestätt
et al (2005). Since selective COX-2 inhibition can provide
analgesic and anti-inflammatory effects with reduced undesirable gastric side
effects, COX-2 selective inhibitors such as celecoxib and rofecoxib have become
some of the most widely used prescription medications in the developed world.
However, recent reports that COX-2 selective inhibitors may increase the risk
of heart attack in some patients has caused great concern, and stimulated
increased interest in these enzymes, Masferrer et al (1994) and Solomon et al
(2002).
Figure 5: Structures
of Celecoxib and Rofecoxib In this paper we
have reported the successful synthesis as well the determination of the binding
energies of novel ethyl-glycinate amide derivatives with the COX-2 construct
which was used to obtain the 1CVU crystal structure for molecular docking in
order compare their binding energy with the standard drugs, celecoxib and
rofecoxib respectively used as COX-2 inhibitors. This is to determine if these
derivatives could also serve as good drug molecules that can inhibit COX-2
enzyme or not. 2. EXPERIMENTALAll the reagents
were purchased from commercial supplier, Aldrich, and
were used without further purification. Melting points were determined
with electro thermal melting points apparatus in open capillaries and are uncorrected.
UV and Visible spectra were recorded in DMF on a Jenway 6405 UV/Vis
spectrophotometer, using matched 1cm quartz cell. IR spectra in (KBr) on a FTIR
(NARICT, Zaria), 1H–NMR and 13C-NMR on a JEOL Associate
E-400 instrument (chemical shift are reported on the δ scale relative to
tetramelthylsilane (TMS) as an internal standard) and mass spectra on a
Shimadzu QP2010 spectrophotometer. Analytical samples were obtained by column
chromatography on aluminum oxide 90 (Merck, 70–230 Mesh ASTM) employing ethano-chloroform
(9:1) as eluting solvent before recrystallization. The 3.0 Å resolution X-ray
crystal structure of the ovine COX-1/AA complex, pdb entry 1CVU, was used to
generate the initial model. 2.1. ETHYL GLYCINATE 29The compound glycine
ethyl ester 98 was prepared by using
the esterification reaction of glycine 1
with ethanol in the presence of hydrochloric acid as a catalyst, Jiabo and
Yaowu (2008) and Fischer and Speier (1895). A mixture of glycine (15.0g,
0.15mol), ethanol (200ml) and conc. hydrochloric acid (7ml) was refluxed for
15h, at 78oC. At the end of the reaction, the mixture was placed in
a water bath and evaporated. The evaporated product was kept in an airtight
desiccator for a week and a crystalline whitish product was obtained. This was later recrystallized from ethanol
mixed with a little quantity of diethyl ether to precipitate the final product
(14.50g, 96.5%). This was further dried for some days and brilliant white
crystals were obtained, melting at 188. 2oC.The UV-Vis: λmax,
334nm (ε = 8.4). IR (KBr): 3119cm-1 (N-H stretching), 2838cm-1
(C-H stretching), 1718 cm-1 (C=O stretching), 1490cm-1(C-N
stretching), 1244cm-1 (C-O stretching).1H-NMR (DMSOd6)
δ ppm: 8.70 (singlet, 2H, 1o amine), 4.16 (triplet, 2H,
methylene protons), 4.04(singlet, 2H, methylene protons), 1.2 (doublet, 3H,
methyl protons). 13C-NMR (DMSOd6) δ ppm: 167.6 (1C,
carbonyl), 61.0 (1C, methylene), 41,8 (1C, methylene), 14.6 (1C, methyl). 2.2. 2-AMINO-N- (4-NITROPHENYL) ACETAMIDE (31)The compound,
2-amino-N-(4-nitrophenyl) acetamide 31 was prepared by the reaction of the
synthesized glycine ethyl ester 29 (2.0g,
0.02mol) and 4-nitroaniline 30 (2.0g,
0.01mol) with the stoichiometric ratio of 2:2. Both compounds were dissolved in
(50ml) ethanol and boiled under reflux for 4h. The crude product was obtained
with the help of a rotary evaporator under reduced pressure. This was dried and
subjected to column chromatography using a mixture of ethanol and chloroform
(9:1) as eluting solvent followed by recrystallization, to give a
brown-yellowish compound 31, yield
3.76g (94.0%), melting point, 186.2oC. UV-Vis -λmax(ε)
344nm (18.0) 364nm (19.5) 425nm (22.2) 445nm (21.6) 465nm (21.3).IR (KBr):
3481cm-1(N-H stretching), 2838cm-1(C-H stretching),
1751cm-1(C=O stretching) 1625cm-1(C=C stretching),
1584cm-1(C-N stretching), 913cm-1(C-H bending out of
plane of aromatic ring).1H-NMR (DMSOd6) δ ppm: 10.23
(singlet, 1H, amide proton), 8.70 (triplet, 2H, 1oamine protons),
8.17 (doublet, 2H, aromatic protons), 7.82 (doublet, 2H, aromatic protons),
3.85 (triplets 2H, methylene protons). 13C-NMR (DMSOd6)
δ ppm: 168.5 (1C, carbonyl), 144.6 (1C, Aromatic-C-NO2), 143.5
(1C, Aromatic-C-N), 124.1 (2C, aromatic), 119.9 (2C, aromatic), 43.2 (1C,
methylene). 2.3. 2-AMINO-N-(6-METHYLPYRIDIN-2-YL) ACETAMIDE 33The compound
2-Amino-N-(6-methylpyridyl) acetamide
33 was prepared by the reaction of
ethyl glycinate 29 (2.0g, 0.02mol)
and 2-amino-6-methylpyridine 32
(2.0g, 0.02mol) in the ratio of 2:2 respectively. These compounds were
dissolved in 50mlethanol and boiled under reflux for 4h. The crude product was
obtained with the help of a rotary evaporator under reduced pressure. This was
dried and subjected to column chromatography using a mixture of ethanol and
chloroform (9:1) as eluting solvent followed by recrystallization, to give a
whitish crystalline compound 33,
yield 3.56g (89.0%), melting at 202.1oC. UV-Vis -λmax(ε);
354nm (15.09); IR (KBr): 3090cm-1(N-H stretching), 2806cm-1
(C-H stretching), 1662cm-1(C=O stretching), 1572cm-1(C=N
stretching), 924cm-1 (C-Hbending of aromatics).1H-NMR
(DMSOd6) δ ppm: 11.14 (singlet, 1H, amide proton), 8.70
(triplet, 2H, 1oamine protons), 8.17 (doublet, 2H, aromatic protons),
7.96 (singlet, 1H, aromatic proton),7.89 (singlet, 1H, aromatic proton), 6.88
(singlet, 1H, aromatic proton), 3.85 (triplets 2H, methylene protons);13C-NMR
(DMSOd6) δ ppm: 168.5 (1C, carbonyl), 151.5 (2C, aromatic-C-N),
149.5 (1C, aromatic-C-N), 143.5 (1C, C-NO2), 125.5 (1C, aromatic),
112.8 (2C, aromatic), 43.2 (1C, methylene), 23.9 (1C, methyl). 2.4. N, N'-(1,4-PHENYLENE)-BIS-(2-AMINOACETAMIDE) 35The compound
1,4-(2,2-diamino-N, N’-phenyl)
diacetamide 35 was prepared by the
reaction of glycine ester 29 (2.0g,
0.02mol) and 1,4-diamino-N, N’-benzene
34 (1.0g, 0.01mol) with the ratio of
2:1 respectively. Both compounds were dissolved in 50ml ethanol and left to
boil under reflux for 4h, thereafter the crude product was obtained with the
help of a rotary evaporator under reduced pressure. This was dried and
subjected to column chromatography using a mixture of ethanol and chloroform
(9:1) as eluting solvent followed by recrystallization, to give a black
compound 35, yield 2.84g (94.7%),
melting at 235.4oC. UV-Vis -λmax(ε); 354nm
(20.3) 420nm (24.8) 547nm (28.7) 597nm (29.6); IR (KBr): 3451cm-1(N-H
stretching), 2944cm-1(C-H stretching), 1668cm-1(C=O
stretching), 1386cm-1 (C-N stretching), 682cm-1 (C-H
bending of aromatics).1H-NMR (DMSOd6) δ ppm: 10.23 (singlet,
2H, amide protons), 8.70 (triplet, 4H, 1oamine protons), 7.57
(singlet, 4H, aromatic protons), 3.85 (triplets 4H, methylene protons); 13C-NMR
(DMSOd6) δ ppm: 168.5 (2Cs, carbonyl), 134.1 (2C,
aromatic-C-N), 121.8 (4C, aromatic-C-N), 43.2 (1C, methylene). 2.5. N, N'-(6-CHLOROPYRIMIDINE-2,4-DIYL)-BIS-(2-AMINOACETAMIDE) 37The compound
2,6-(2,2-diamino-N, N’-4-chloropyrimidyl)
diacetamide 37was prepared by the
reaction of ethyl glycinante 29
(2.0g, 0.02mol) and 2,6-diamino-4-chloro-pyrimidine 36 (1.0g, 0.01mol) with the ratio of 2:1. Both compounds were
dissolved in 50ml ethanol and left to boil under reflux for 4h, thereafter the
crude product was obtained with the help of a rotary evaporator under reduced
pressure. This was dried and subjected to column chromatography using a mixture
of ethanol and chloroform (9:1) as eluting solvent followed by
recrystallization, to give a whitish compound 37, yield 1.48g (49.6%), melting at 168.6oC. UV-Vis
-λmax(ε); 344nm (3.6). IR (KBr): 3451cm-1(N-H
stretching), 3011cm-1(C-H stretching), 1684cm-1(C=O
stretching) 1628cm-1 C=N stretching,874cm-1 (C-H bending
of aromatics). 1H-NMR (DMSOd6) δ ppm: 11.14
(singlet, 1H, amide protons), 10.30 (singlet, 1H, amide protons) 8.70 (triplet,
4H, 1oamine protons), 8.14 (singlet, 4H, aromatic protons), 3.80
(singlet 4H, methylene protons); 13C-NMR (DMSOd6) δ
ppm: 168.5 (2Cs, carbonyl), 161.4 (1C, aromatic-Cl), 147.6 (1C, aromatic-C-N),
105.5 (2C, aromatic), 43.2 (2C, methylene). 2.6. 2-AMINO-N-(4-HYDROXY-6-UREIDOPYRIMIDIN-2-YL) ACETAMIDE 39The compound
2,4-(diamino- N, N’-6-hydroxypyrimidyl)
diacetamide 39 was prepared from the
reaction of ethyl glycinate 29
(2.0g, 0.02mol) and 2,4-diamino-6-hydroxypyrimidine 38 (1.0g, 0.01mol) with the ratio of 2:1. Both compounds were
dissolved in 50ml ethanol and left to boil under reflux for 4h, thereafter the
crude product was obtained with the help of a rotary evaporator under reduced
pressure. This was dried and subjected to column chromatography using a mixture
of ethanol and chloroform (9:1) as eluting solvent followed by
recrystallization, to give a whitish crystalline compound 39, yield 2.77g (94.7%), melting at 227.3oC.UV-Vis
-λmax(ε); 359nm (19.9); IR(KBr): 3324cm-1 O-H
stretching, 3281cm-1 (N-H stretching), 2993cm-1(C-H
stretching), 1673cm-1(C=O stretching), 1506cm-1 (C=N
stretching) 1133cm-1(C-O stretching), 883cm-1 (C-H
bending).1H-NMR (DMSOd6) δ ppm: 11.62 (s, 1H, OH),
11.14 (singlet, 1H, amide protons), 10.30 (singlet, 1H, amide protons) 8.70 (triplet,
4H, 1oamine protons), 7.37 (singlet, 4H, aromatic protons), 3.80
(singlet 4H, methylene protons); 13C-NMR (DMSOd6) δ
ppm: 168.5 (2Cs, carbonyl), 167.5 (1C, aromatic-OH), 151.3 (1C, aromatic-C-N),
138.8 (1C, aromatic-C-N), (101.3 (1C, aromatic), 43.2 (2C, methylene). 2.7. MOLECULAR DOCKING EXPERIMENTS2.7.1. PREPARATION OF LIGANDS The docking studies
were carried out on a Zinox Laptop, Model T5101. ACD/ Chemdraw 2015 (Ref: ACD/Structure Elucidator,
version 15.01, Advanced Chemistry Development, Inc., Toronto, ON, Canada,
www.acdlabs.com, 2015.) was used to draw the
structures of compounds 31-39 (Figs. 6 ,7,10, 13, 16, 19 and 22) and also convert them to 3D formats. 2.7.2. PREPARATION OF PROTEIN TARGETS The 3D
structure of the cyclooxygenase
active site of COX-2(PDB: 1CVU) was retrieved from the RCSB Protein Data Bank (PDB) (www.rcsb.org/pdb/home/home.do),
Picot et al (1994). All bound ligands, cofactors,
andwater molecules were removed from the proteins using Discovery Studio
Visualizer v16. 1.0. 15,350. All file conversions required for the docking
study were performed using the open source chemical toolbox. Open Babel version
2.3.2 (www.openbabel.org). Finally Auto Dock
was used to calculate the binding free energy of a given inhibitor conformation
in the macromolecular structure. Figure 6: Structure of Cyclooxygenase-2 (+-PDB: 1CVU) 3. RESULT AND DISCUSSIONSThe synthesis of ethyl glycinate 29 was achieved through Fischer esterification protocol, Jiabo and
Yaowu (2008) and Fischer and Speier (1895) whereas its amide derivatives;
2-amino-N-(nitrophenyl)acetamide 31, 2-amino-N-(6-methylpyridin-2-yl) acetamide 33, N,N'-(1,4-phenylene)bis-(2-aminoacetamide)
35, N,N'-(6-chloropyrimidine-2,4-diyl)bis-(2-aminoacetamide) 37, and 2,4-(diamino-N,N’-6-hydroxypyrimidyl)acetamide 39 respectively were synthesized by
coupling reactions of the following starting reagents namely; 4-nitroaniline,
2-amino-6-methylpyridine, 1,4-diamino-N,N’-benzene,
2,6-diamino-4-chloropyrimidine and 2,4-diamino-6-hydroxypyrimidine respectively
with the key intermediate, ethyl glycinate 29,
FitzGerald (200). These compounds were characterized on the basis of their
melting points, UV-Visible, IR, 1HNMR and 13CNMR
spectroscopic analyses. The results obtained from the spectra were consistent
with the assigned structures of the compounds. The 1HNMR and 13CNMR
spectra as well as the reaction schemes for the
synthesis of the above compounds are outline in the Figs (6-22) below; Figure 7: Reaction scheme for the synthesis of ethyl
glycinate Figure 8:1HNMR spectrum of ethyl glycinate (29) Figure 9: 13CNMR spectrum of ethyl glycinate (29) Figure 10: Reaction scheme for the synthesis of
2-amino-N-(4-nitrophenyl) acetamide (31) Figure 11:1HNMR spectrum of 2-amino-N-
(4-nitrophenyl) acetamide (31) Figure 12:13CNMR spectrum of 2-amino-N-
(4-nitrophenyl) acetamide (31) Figure 13: Reaction scheme for the synthesis of
2-Amino-N-(6-methylpyridin-2-yl)
acetamide (33) Figure 14:1HNMR spectrum of 2-Amino-N-(6-methylpyridin-2-yl)
acetamide (33) Figure 15: 13CNMR spectrum of 2-Amino-N-(6-methylpyridin-2-yl) acetamide (33) Figure 16: Reaction scheme for the synthesis of N, N'-(1,4-phenylene)-bis-(2-aminoacetamide) (35) Figure 17:1HNMR spectrum of N, N'-(1,4-phenylene)-bis-(2-aminoacetamide) (35) Figure 18: 13CNMR spectrum of N, N'-(1,4-phenylene)-bis-(2-aminoacetamide) (35) Figure 19: Reaction scheme for the synthesis ofN, N'-(6-Chloropyrimidine-2,4-diyl)-bis-(2-aminoacetamide) (37) Figure 20:1HNMR
of N, N'-(6-Chloropyrimidine-2,4-diyl)-bis-(2-aminoacetamide) (37) Figure 21: 13CNMR of N, N'-(6-Chloropyrimidine-2,4-diyl)-bis-(2-aminoacetamide) (37) Figure 22: Reaction scheme for the synthesis of
2-amino-N-(4-hydroxy-6-ureidopyrimidin-2-yl)acetamide (39) Figure 23: 1HNMR of 2-amino-N-(4-hydroxy-6-ureidopyrimidin-2-yl)
acetamide (39) Figure 24: 13CNMR of 2-amino-N-(4-hydroxy-6-ureidopyrimidin-2-yl)
acetamide (39) The synthesized
compounds were subjected to molecular docking with
a target protein, 1CVU to compare their binding energies with celecoxib
and rofecoxib which are used as standard drugs for the inhibition of COX2
enzyme, Kurumbail (1994). From the docking result, the binding energy values of
the above synthesized compounds were found to be -5.8 kJmol-1, -6.2
kJmol-1, -7.2 kJmol-1, -7.4 kJmol-1 and -7.6
kJmol-1 respectively as shown in table 1 and the chart in Fig 23
below. These values are actually below that of the standard drugs; however
compound (39) showed the highest
binding energy of -7.6 kJmol-1, close to that for celecoxib and
rofecoxib whose values are -8.0 kJmol-1 and -8.2 kJmol-1
respectively. This result indicates that compound (39) possess some level of inhibitory activity against COX2. Table 1: Binding energy (∆G (kJ/mol) of the synthesized
compounds with target protein, 1CVU
Figure 25: A chart comparing the binding
energies of the synthesized compounds and the standard inhibitory drugs for
COX2, celecoxib and rofecoxib respectively.
4. CONCLUSIONFive
new derivatives of ethyl glycinate bearing carboxamide pharmacophores have been
synthesized and characterized in this work. All the compounds showed
appreciable binding energies ranging from − 5.8 to -7.6 kcal/mol with
target protein, 1CVU. Compound showed the highest binding energy of 7.6
kcal/mol. Although the binding energies values were not as high as that of the
standard drugs used, these novel compounds could be used as starting materials
for the synthesis of drugs that can inhibit COX2 enzyme responsible for causing
inflammation in the body. SOURCES OF FUNDINGThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. CONFLICT OF INTERESTThe author have declared that no competing interests exist. ACKNOWLEDGMENTNone. REFERENCES
[1]
Young VR
(1994). "Adult amino acid requirements: the case for a major revision in
current recommendations" J. Nutr. 124 (8 Suppl): 1517–1523.
doi:10.1093/jn/124.
[2]
Dietary
Reference Intakes: The Essential Guide to Nutrient Requirements Archived 5 July
2014 at the Way back Machine. Institute of Medicine's Food and Nutrition Board.
usda.gov.
[3]
W. Wang,
Z. Wu, Z. Dai, Y. Yang, J. Wang, and G. Wu, (2013) “Glycine metabolism in
animals and humans: implications for nutrition and health,” Amino Acids, vol.
45 (3), 463–477.
[4]
Wu G
(2009) “Amino acids: metabolism, functions, and nutrition”, Amino Acids”
37,1–17
[5]
Darling
PB, Dunn M, Sarwar G et al (1999) “Threonine kinetics in preterm infants fed
their mothers’ milk or formula with various ratios of whey to casein”. American
Journal of ClinicalNutrition, 69,105–114
[6]
Jackson
AA (1991) “The glycine story”. European Journal of Clinical Nutrition 45, 59–65
[7]
Melendez-Hevia
E, De Paz-Lugo P, Cornish-Bowden A et al (2009) “A weak link in metabolism: the
metabolic capacity for glycine biosynthesis does not satisfy the need for
collagen synthesis”. Journal of Bioscience 34, 853–872
[8]
Rezaei
R, Wang WW, Wu ZL et al (2013) “Biochemical and physiological bases for
utilization of dietary amino acids by young pigs”. Journal of Animal Science
Biotechnology 4 (7).
[9]
R.
Senthilkumar and N. Nalini, (2004) “Glycine modulates lipids and lipoproteins
levels in rats with alcohol induced liver injury,” Internet Journal of
Pharmacology, 2 (2), 1-12.
[10] Zeb and S. U. Rahman, (2017) “Protective
effects of dietary glycine and glutamic acid toward the toxic effects of oxidized
mustard oil in rabbits,” Food Function.,8 (1), 429–436.
[11] P. A. Abello, T. G. Buchman, and G. B.
Bulkley, (1994) “Shock and multiple organ failure,” Advances of Experimental
Medicine andBiology, 366 (2), 253–268.
[12] M. Yin, R. T. Currin, X.-X. Peng, H. E.
Mekeel, R. Schoonhoven, and J. J. Lemasters, (2002) “Carolina rinse solution
minimizes kidney injury and improves graft function and survival after
prolonged cold ischemia,” Transplantation, 73 (9), 1410–1420.
[13] R. M. Lewis, K. M. Godfrey, A. A. Jackson, I.
T. Cameron, and M. A. Hanson, (2005) “Low serine hydroxymethyl transferase
activity in the human placenta has important implications
[14] IUPAC, Compendium of Chemical Terminology,
2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "esters".
doi:10.1351/goldbook.E0221
[15] Montalbetti, Christian A. G. N.; Falque,
Virginie (2005). "Amide bond formation and peptide coupling".
Tetrahedron. 61 (46): 10827–10852. Doi:10.1016/j.tet.2005.08.031.
[16] Smith, Michael B.; March, Jerry (2007),
Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.), New
York: Wiley-Interscience, ISBN 978-0-471-72091-1
[17] Mohamed I. Hegab, Abdel-Samee M. Abdel-
Fattah, Nabil M. Yousef (2007), “Synthesis, X-ray structure and Pharmacological
activity of some 6,6-disubstituted chromeno[4,3-b] and
chromeno-[3,4-c]-quinolines; Archiv der Pharmazie, Chemistry in Life Sciences
340(8), 396-399.
[18] Nadeem Siddiqui, ShamsherAlam, Waquar Ahsan
(2008), “Synthesis, anticonvulsant and toxicity evaluation of 2-(1H-indol-3-yl)
Acetyl-N- (substituted phenyl) hydrazine carbothioamides and their related
heterocyclic derivatives”,ActaPharma. 58(3), 445-454.
[19] Galewicz-Walesa K. and Pachuta-Stec A.
(2003), “The synthesis and properties of N-substituted amides of
1-(5-methylthio-1, 2, 4-triazol-3-yl) - cyclohexane-2-carboxylic acid”, Medical
Academy in Lublin, 12(9), 118-125.
[20] Graybill, T. L, Ross, M. J.; Gauvin, B. R,
Gregory, J. S, Harris, A. L, Ator, M. A, Rinker, J. M, Dolle, R. E, (1992).,
“Bioorganic Medicinal Chemistry Letter”. Journal of Biological Sciences, 12(1),
1375-1380.
[21] Mihaelamoise, ValeriuSunel, LenutaProfire,
Marcel Popa, Catalina Lionte (2008), “Synthesis and antimicrobial activity of
some new (sulfonamidophenyl)-amide derivatives of N-(4-
nitrobenzoyl)-Phenylalanine”. Journal of Pharmaceutical Sciences. 23(19),
113-121.
[22] Andre Warnecke, IdunaFichtner, Gretel Sab,
Felix Kratz (2007), “Synthesis, Cleavage Profile and antitumor efficacy of an
Albumin- Binding Prodrug of Methotrexate that is cleaved by Plasmin and
Cathepsine B”, Archiv der Pharmazie, Chemistry in Life Sciences, 340(8), 12-25
[23] Ledmicer D. and Mitschen L.A. (1980), “The
organic drug synthesis”, John Wiley and Sons, (2) 248, 226-233.
[24] Delegado J. N. and Remers W.A. (2004), “Test
book of organic medicinal and pharmaceutical chemistry”, Wilson and
GisvoldsLippin. Catt. Raven Philadelphia, 204 (2), 15-68.
[25] Surrender Kumar, D.K. Tyagi and Arun Gupta
(2010), “synthesis and evaluation of amide prodrugs of diclofenac” Journal of
Pharmaceutical Science and Research. 2 (6), 369-375.
[26] Kristina E. Furse, Derek A. Pratt, Ned A.
Porter,and Terry P. Lybrand (2006)Molecular Dynamics Simulations of Arachidonic
Acid Complexes with COX-1 and COX-2, Insights into Equilibrium Behavior; Biochemistry. 2006 March 14; 45(10):
3189–3205.
[27] Liu J, Seibold SA, Rieke CJ, Song I, Cukier
RI, Smith WL (June 2007). "Prostaglandin endoperoxide H synthases:
peroxidase hydroperoxide specificity and cyclooxygenase activation". The
Journal of Biological Chemistry. 282 (25): 18233–44. doi:
[28] Högestätt ED, Jönsson BA, Ermund A, Andersson
DA, Björk H, Alexander JP, Cravatt BF, Basbaum AI, Zygmunt PM (September 2005).
"Conversion of acetaminophen to the bioactive N-acylphenolamine AM404 via
fatty acid amide hydrolase-dependent arachidonic acid conjugation in the
nervous system". The Journal of Biological Chemistry. 280 (36): 31405–12.
Doi:10.1074/jbc.
[29] Masferrer JL, Zweifel BS, Manning PT, Hauser
SD, Leahy KM, Smith WG, Isakson PC, Seibert K (1994). Selective inhibition of
inducible cyclooxygenase-2 in vivo is anti-inflammatory and non-ulcerogenic.
Proc. Natl. Acad. Sci. 91:3228–3232.
[30] Solomon DH, Glynn RJ, Levin R, Avorn J
(2002). Nonsteriodal anti-inflammatory drug use and acute myocardial
infarction. Arch. Intern. Med.162: 1099–1104.
[31] FitzGerald GA. Coxibs and cardiovascular
disease. N. Engl. J. Med. 2004; 351:1709–1711.
[32] Emil Fischer, Arthur Speier (1895).
"Darstellung der Ester". ChemischeBerichte. 28 (3): 3252–3258.
Doi:10.1002/cber.189502803176.
[33] Jiabo Li and Yaowu Sha (2008), “A convenient
synthesis of amino acid methyl esters”. Journal of Biological Sciences. 13(2),
12-17.
[34] PDB: 1CQE; Picot D, Loll PJ, Garavito RM
(January 1994). "The X-ray crystal structure of the membrane protein
prostaglandin H2 synthase-1". Nature. 367 (6460): 243–9.
doi:10.1038/367243a0.
[35] PDB: 6COX; Kurumbail RG, Stevens AM, Gierse
JK, McDonald JJ, Stegeman RA, Pak JY, Gildehaus D, Miyashiro JM, Penning TD,
Seibert K, Isakson PC, Stallings WC (1996). "Structural basis for
selective inhibition of cyclooxygenase-2 by anti-inflammatory agents".
Nature. 384 (6610): 644–8. Doi:10.1038/384644a0.
This work is licensed under a: Creative Commons Attribution 4.0 International License © Granthaalayah 2014-2020. All Rights Reserved. |