Novel sulfamate derivatives of menthol: Synthesis, characterization, and cholinesterases and carbonic anhydrase enzymes inhibition properties

Article abstract of DOI:10.1002/ardp.201800209

Sulfamates have a large spectrum of biological activities including enzyme inhibition. Eight sulfamates derived from menthol (2a–h) were synthesized. Also, in the other section of this study, novel sulfamate derivatives of menthol were tested against some metabolic enzymes including acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and carbonic anhydrase I and II enzymes (hCAs I and II). The newly synthesized novel menthol sulfamate and menthol carbonyl sulfamate derivatives showed K_i values in the range of 34.37 ± 8.17 to 53.40 ± 10.61 nM against hCA I, 12.91 ± 4.57 to 38.67 ± 6.22 nM against hCA II, 111.17 ± 52.36 to 522.86 ± 120.08 nM against AChE, and 50.01 ± 11.73 to 109.63 ± 50.08 nM against BChE. As a result, the novel menthol sulfamate and menthol carbonyl sulfamate derivatives can be promising Alzheimer's disease drug candidates and novel hCA I and hCA II enzymes inhibitors.

Full text of DOI:10.1002/ardp.201800209

Received: 16 July 2018
Revised: 13 August 2018
Accepted: 1 September 2018
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DOI: 10.1002/ardp.201800209
FULL PAPER
Novel sulfamate derivatives of menthol: Synthesis,
characterization, and cholinesterases and carbonic
anhydrase enzymes inhibition properties
Shahla Daryadel1
Murat Çelik1
Ufuk Atmaca1,2
Parham Taslimi1
İlhami Gülçin1
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1 Faculty of Science, Department of
Chemistry, Ataturk University, Erzurum,
Turkey
Abstract
Sulfamates have a large spectrum of biological activities including enzyme inhibition.
Eight sulfamates derived from menthol (2a–h) were synthesized. Also, in the other
section of this study, novel sulfamate derivatives of menthol were tested against some
metabolic enzymes including acetylcholinesterase (AChE), butyrylcholinesterase
(BChE), and carbonic anhydrase I and II enzymes (hCAs I and II). The newly synthesized
novel menthol sulfamate and menthol carbonyl sulfamate derivatives showed Ki values
in the range of 34.37 8.17 to 53.40 10.61 nM against hCA I, 12.91 4.57 to
38.67 6.22 nM against hCA II, 111.17 52.36 to 522.86 120.08 nM against AChE,
and 50.01 11.73 to 109.63 50.08 nM against BChE. As a result, the novel menthol
sulfamate and menthol carbonyl sulfamate derivatives can be promising Alzheimer's
disease drug candidates and novel hCA I and hCA II enzymes inhibitors.
2 Oltu Vocational School, Ataturk University,
Erzurum, Turkey
Correspondence
Prof. Dr. Murat Çelik, Faculty of Science,
Department of Chemistry, Ataturk University,
TR-25240 Erzurum, Turkey.
Email: mcelik@atauni.edu.tr
Funding information
TUBİTAK, Grant number: 113Z700
K E Y W O R D S
acetylcholinesterase, butyrylcholinesterase, carbonic anhydrase, enzyme inhibition, sulfamate
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1
INTRODUCTION
cold-sensitive present in the skin when it is applied to the skin or
inhaled.[4] Menthol is commonly used as an antibacterial agent toward
Sulfamates are commonly known biologically active compounds. Most
medicines contain these functional groups. Sulfamates are widely used
as therapeutic agents in medical chemistry. The sophistication of
sulphamoyl chloride as advances sulfamate derivatives has been widely
used for the synthesis of novel classes of such compounds.[1,2] In recent
years, the improvement of an efficient strategy for the amination of
allylic or benzylic alcohols has attracted considerable interest to organic
chemists and pharmacists. The conversion of alcohols to amines using
mercuryacetatewasreportedin2009.Theuseofmetalinthereactionis
discussed as green chemistry. It has been also achieved the allylic
amination of allylic alcohols with sodium sulfate and sodium carbon-
ate.[3] Menthol is known to chemically trigger transient receptor
potential of cation channel subfamily M member eight receptors the
various lactobacilli and streptococci in dental care.[5]
In our work, we have realized that the equivalent amount of
chlorosulphonyl isocyanate (CSI), allylic or benzyl sulfamate menthol
derivatives can be synthesized from alcohols with high efficiency without
using any additives or catalysts. We have studied the reaction (Table 1)
with high yields of mentholic sulfamate compounds resulting from
reaction of commercially available allylic or benzylic alcohols with CSI in
dichloromethane.
Carbonic anhydrase (CA) isoforms are metalloenzymes that
participate in the conservation of pH homeostasis in the cells
by catalyzing the reversible hydration of carbon dioxide (CO2) and
water to protons (H+) and bicarbonate ions (HCO3−).[6–8] The CO2/
−
HCO3 buffer method predominantly controls maintenance of an
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Arch Pharm Chem Life Sci. 2018;e1800209.
wileyonlinelibrary.com/journal/ardp
© 2018 Deutsche Pharmazeutische Gesellschaft
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https://doi.org/10.1002/ardp.201800209

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TABLE 1 Amination of allylic and benzylic alcohols (1a–h) formation of menthol sulfamates (2a–e) and menthol carbonyl sulfamates (2f–h)a
Entry
Substrate
Product
Yield (%)b
1
78
2
3
70
65
4
5
68
70
6
7
72
73
8
68
aThe reactions were carried out in dichloromethane at 1 eq. CSI and room temperature.
bIsolated yield of pure materials.
appropriate pH in the brain cells, and CA isoforms actively control this
equilibrium by hydrolyzing the interconversion of two compounds/
ions.[9,10] Hence, CA isoforms are promising aims to control seizures as
some of the clinically good antiepileptic drugs have shown efficient CA
inhibitory activity.[11] In the brain cells, various CA isoenzymes exist and
are actively involved in diverse neurophysiologic or neuropathophysio-
logic mechanisms. CA II isoform is mostly expressed in the choroid
plexus, astrocytes, oligodendrocytes, myelin sheaths, and myelinated
tracts and overexpressed in multiple central nervous system disturban-
ces including epilepsy.[12,13]

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Alzheimer's disease (AD) is accompanied by an increase of
acetylcholinesterase (AChE) activity that leads to run out of cholinergic
neurotransmission in the brain areas related to memory and
learning.[14,15] Amyloid beta-protein plaques, the major pathological
sign in the brain of AD patients, are a degradation product of
cholinesterase (ChE) enzyme. Currently, there are several approved
drugs as AChE inhibitors (AChEIs) including donepezil, rivastigmine,
and galantamine for the treatment of AD.[16,17] These drugs increase
acetylcholine (ACh) level in the central nervous system to enhance
cholinergic neurotransmission.[18] The inhibition of both hydrolysis
products of ACh had crucial importance in AD. Both cholinergic
enzymes are essential for successful treatment of AD because recent
studies in AD patients reported that while the AChE activity is
significantly reduced in specific regions of the brain, BChE activity can
increase.[19,20] Adverse effects of some synthetic AChEIs used for the
treatment of AD such as tacrine and donepezil led us to find innocent
and most potent derivatives of that drugs.[21,22] Therefore, it is very
important to find new substances, more efficient and less expensive
than the currently used drugs, is urgently needed.
SCHEME 1 Synthesis of 2-isopropyl-5-methylcyclohexyl
cyclohex-2-en-1-ylsulfamate (2a)
the menthol sulfamates associated with the substitution of sulfamoyl
chlorides with rac-menthol-Li (4) with decarboxylation at the
opening of the cyclobutane ring (Scheme 3). Thus, we achieved
the synthesis of menthol sulfamate derivatives from acyclic or cyclic
benzylic and allylic alcohols without any additive or catalyst by using
CSI (Table 1).
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2.2 Biological activities
In this study, all the synthesized compounds (novel menthol sulfamate
(2a–e) and menthol carbonyl sulfamate (2f–h) derivatives) were tested
to investigate their inhibitory activity toward the hCA I, the rapid
cytosolic hCA II, AChE, and BChE enzymes. The chemical formula and
reactions of novel menthol sulfamate (2a–e) and menthol carbonyl
sulfamate (2f–h) derivatives are given in Schemes 1–3. Their enzymes
inhibition data are summarized in Table 2. Many CA isoforms are of
therapeutic purposes to fight some disturbances like epilepsy, obesity,
cancer, oedema, and glaucoma.[24,25] Sulfonamide compounds are the
most significant class of CA inhibitors (CAIs), with various compounds
such as acetazolamide (AZA), valdecoxib, sulthiame, dorzolamide,
topiramate, dichlorophenamide, brinzolamide, methazolamideethox-
zolamide, zonisamide, celecoxib, and sulpiride, which are available in
the drug market for the therapy of glaucoma.[26,27]
In this study, we aimed to investigate the inhibitory effects of
newly synthesized menthol sulfamate (2a–e) and menthol carbonyl
sulfamate (2f–h) derivatives against hCA I, hCA II, BChE, and AChE
enzymes.
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2
RESULTS AND DISCUSSION
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2.1 Chemistry
Our research group has previously carried out the reaction of the
sulfamoyl chlorides with the alcohols and amines.[23] The amination of
allylic or benzylic alcohols with CSI was efficiently carried out and
sulfamoyl chloride at low temperature was provided without any
catalyst or additives. Fresh menthol–Li mixture was added to flask,
which contains sulfamoyl chloride as an intermediate product.
However, when menthol is added to the reaction mixture, the yield
is about 10%. We treated the hydroxyl group of menthol with lithium
to make it more nucleophilic. So we synthesized the menthol
sulfamates (2a–h) with high efficiency.
AD is started with short-term memory loss and progresses
progressively with signs like confusion, impaired communication, poor
judgment, disorientation, behavior changes, and difficulty walking,
speaking, and swallowing.[28,29] In 3–7 years after diagnosis of this
disease, AD ends in death. At subcellular and cellular levels, AD
happens as overproduction of β-amyloid peptides, further extracellular
organization of plaques, synaptic degeneration, intracellular agglom-
eration of hyperphosphorylated τ protein forming neurofibrillary
tangles, and neuronal cell death.[30,31] The death of neurons forcefully
reduces the amounts of ACh in cholinergic brain synapses. By
inhibition of the AChE, which hydrolyzes ACh molecule, the amounts
of ACh are raised and the cholinergic transportation is improved. At
present, the AChEIs, such as donepezil, rivastigmine, and galantamine,
are the principal drugs approved for the treatment of AD.[32,33]
The hCA I isoform is discovered in many mammalian tissues and
occurs in high concentrations in the gastrointestinal tract and blood
cells.[34] It is involved in cerebral edema and retinal, and also the
inhibition of this enzyme can be an important factor for fighting
these situations or diseases.[35] For hCA I isoform, the Ki values
were determined in range of 34.37 8.17 to 53.40 10.61 nM. In
Initially, we examined allylic amination of 2-cyclohexene-1-ol
(1a) with CSI at 0°C, which afforded the corresponding sulfamoyl
chloride. This reaction was performed. Following, 2-isopropyl-5-
methylcyclohexyl cyclohex-2-en-1-ylsulfamate (2a) was obtained by
the nucleophilic reaction of rac-menthol-Li with sulfamoyl chloride as
shown in Scheme 1 and good yields were obtained as shown in Table 1.
However, when same reaction conditions were applied to the
acyclic 3-methylbut-2-en-1-ol (1f), 3-buten-2-ol (1g), and prop-2-en-
1-ol (1h), expected amination product was not formed. Instead of this,
unexpected menthol carbonyl sulfamates (2f–h) were observed
(Scheme 2).
The possible reaction mechanism is shown in Scheme 3. The first
attack on CSI the carbonyl group in the alcohol oxygen is the
resulting oxonium ion (I). It is then converted to the cyclobutane ring
intermediate product (II) by the SNi mechanism. We estimated that

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SCHEME 2 Synthesis of menthol carbonyl sulfamates (2f–h) from acyclic allylic alcohols
comparison, the Ki for the standard CA inhibitor AZA, a definitive hCA I
inhibitor, was 136.57 19.02 nmol/L against hCA I (Table 2). All novel
menthol sulfamate (2a–e) and menthol carbonyl sulfamate (2f–h)
derivatives had effective inhibition effects than that of AZA. Also,
among these compounds, 2-isopropyl-5-methylcyclohexyl ((but-3-
en-2-yloxy)carbonyl)sulfamate (2g), which had 2-isopropyl-5-
methylcyclohexyl, was the best hCA I inhibitor (Ki 34.37 8.17 nM,
Figure 1). It is well known that compounds containing carbonyl (─CO)
and halogen groups are effective CAIs. As shown in Table 1, IC50
values are in the range of 37.97–53.55 nM toward hCA I and
15.97–29.96 nM for hCA II.
inhibition properties. However, the most powerful AChE inhibition
was recorded by novel compound 2e with Ki value of
a
111.17 52.36 nM (Figure 1). Also, all the remaining newly
synthesized compounds reported here were highly efficient inhibi-
tion constants against AChE. On the other hand, tacrine (1,2,3,4-
tetrahydroacridin-9-amine), had Ki value of 605.46 53.27 nM
against cholinergic AChE. Finally, novel menthol sulfamate (2a–e)
and menthol carbonyl sulfamate (2f–h) derivatives inhibited BChE
with Ki values in range of 50.01 11.73 to 109.63 50.08 nM
(Table 2). The Ki values of novel menthol sulfamate (2a–e) and
menthol carbonyl sulfamate (2f–h) derivatives for BChE and AChE
were obtained from Lineweaver–Burk plots. On the other hand,
tacrine, which was the first ChE inhibitor to be discovered for
the management of AD symptoms in 1993, had Ki value of
201.51 40.30 nM. Furthermore, it was considered that donepezil
hydrochloride compound, which is used for the therapy of mild-
to-moderate AD and diverse other memory impairments, had been
shown to lower AChE inhibition activity (IC50: 55.0 nM). As seen in
Table 2, IC50 values are in the range of 206.31–924.01 nM toward
AChE, for BChE are in the range of 91.41–246.26 nM.
−
HCA II inhibition reduces HCO3 production and finally aqueous
humor secretion, which leads to reduced pressure in the eye.[36]
Indeed, hCA II has key role in diseases such as glaucoma disease.
−
Indeed, HCO3 generation serves as a strategy to transport sodium
ions (Na+) into the eye along with the influx of water leading to an
increase in intraocular pressure.[37] Novel menthol sulfamate (2a–e)
and menthol carbonyl sulfamate (2f–h) derivatives synthesized in this
paper significantly inhibited hCA II with Ki in the low nanomolar range.
Ki values were calculated between 12.91 4.57 and 38.67 6.22 nM
(Table 2). On the other hand, 2-isopropyl-5-methylcyclohexyl benzhy-
drylsulfamate (2e), which contains two benzene rings (Figure 1 and
Table 1) is in fact the best inhibitor in this molecules, being 6.33 times a
better hCA II inhibitor compared to the clinical candidate drug (Ki of
AZA: 81.80 12.33 nM). These compounds are also an effective hCA II
inhibitor, being almost four times more effective than AZA in inhibiting
hCA II isoform.
Evaluation of the effects of novel menthol sulfamate (2a–e) and
menthol carbonyl sulfamate (2f–h) derivatives on AChE, BChE, and
hCA I and II enzymes was the important purpose of this paper, and
inhibition results are present in Table 2 and Figure 1. For hCA I and
II isoforms, their excellent inhibitors were 2-isopropyl-5-methylcyclo-
hexyl ((but-3-en-2-yloxy)carbonyl)sulfamate (2g), 2-isopropyl-5-
methylcyclohexyl
(((3-methylbut-2-en-1-yl)oxy)carbonyl)sulfamate
In this work, AChE was also extremely inhibited by novel
menthol sulfamate (2a–e) and menthol carbonyl sulfamate (2f–h)
derivatives at the low nanomolar inhibition with Ki values in range of
111.17 52.36 to 522.86 120.08 nM (Table 2). These results nicely
determined that new-synthesized bromophenols had effective AChE
(2f), and 2-isopropyl-5-methylcyclohexyl ((Z)-cyclooct-2-en-1-yl)
sulfamate (2b). 2-Isopropyl-5-methylcyclohexyl (1-phenylethyl)
sulfamate (2d) compound is a weak inhibitor compared to other
compounds for this isoenzymes. For AChE, their excellent inhibitors
were 2-isopropyl-5-methylcyclohexyl benzhydrylsulfamate (2e) and
SCHEME 3 The possible general reaction mechanism synthesis of menthol sulfamate

DARYADEL ET AL.
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2-isopropyl-5-methylcyclohexyl (1-phenylethyl)sulfamate (2d).
2-Isopropyl-5-methylcyclohexyl benzylsulfamate (2c) compound is
a weak inhibitor compared to other molecules of AChE. For BChE,
their excellent inhibitors were 2-isopropyl-5-methylcyclohexyl
(((3-methylbut-2-en-1-yl)oxy)carbonyl)sulfamate (2f) and 2-isopro-
pyl-5-methylcyclohexyl ((allyloxy)carbonyl)sulfamate (2h). Also, for
hCA II, their excellent inhibitors were 2-isopropyl-5-methylcyclo-
hexyl benzhydrylsulfamate (2e) and 2-isopropyl-5-methylcyclohexyl
(1-phenylethyl)sulfamate (2d).
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CONCLUSION
In summary, starting from the appropriate reagents, the novel 1b–8b
menthol derivative sulfamates were synthesized. The synthesized
menthol derivative sulfamates may be important for biological and
synthetic purposes. In this study, newly synthesized racemic menthol
derivative sulfamates (1b–8b) were evaluated against cytosolic hCA I,
hCA II, AChE, and BChE enzymes. All menthol derivative sulfamates
haveshownlownanomolarinhibitionagainstusedmetabolicenzymes.
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4
EXPERIMENTAL
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4.1 Chemistry
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4.1.1 General
All solvents and chemicals are commercially available. IR spectra
were obtained from solutions in 0.1 mm cells and in CH2Cl2 with a
Perkin-Elmer spectrophotometer. 1H and 13C NMR spectrums were
recorded on Varian and Bruker spectrometers at 400 and 100 MHz,
respectively, and NMR shifts are presented. Elemental analyses were
performed on LECO CHNS-932 apparatus. All column chromatogra-
phy was performed on silica gel (60-mesh, Merck).
The InChI codes of the investigated compounds together with
some biological activity data are provided as Supporting Information.
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4.1.2 General procedure for the synthesis of
menthol sulfamates
Allyl or benzyl alcohol (1.0 eq) was dissolved in 20 mL DCM. The reaction
mixture was cooled to 0°C and CSI (1.1 eq) was added and resulting
solution was stirred for 1 h (Scheme 4). Then, in a separate flask,
menthol-Li (3) was prepared in THF with lithium (1.1 mol). Fresh
menthol-Li (4) was added to the reaction mixture and stirred for 0.5 h.
The reaction mixture was extracted with dichloromethane. The organic
phase was dried over sodium sulfate and concentrated. Purification was
performed through column chromatography on silica gel.
2-Isopropyl-5-methylcyclohexyl cyclohex-2-en-1-ylsulfamate
(2a)
Yield 78% as a colorless liquid. IR (CH2Cl2, cm−1): 3238, 2952, 2926,
2868, 1742, 1720, 1457, 1383, 1289, 1232, 1174, 1049, 916;

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FIGURE 1 Determination of Lineweaver–Burk graphs for excellent inhibitors of human carbonic anhydrase I (2g) and II (2e) isoenzymes,
acetylcholinesterase (AChE) (2e), and butyrylcholinesterase (BChE) (2f) enzymes
1H NMR (400 MHz, CDCl3, ppm): δ = 7.22 (bs, 1H), 6.02 (m, 1H),
5.72–5.99 (m, 1H), 5.26 (m, 1H), 4.60 (td, J = 11.7, 21.6 Hz, 1H), 0.79–
2.34 (m, 25H). 13C NMR (100 MHz, CDCl3, ppm): δ = 134.4, 124.5,
47.9, 41.4, 33.9, 31.9, 29.9, 28.3, 25.5, 25.0, 23.2, 22.1, 21.1, 18.6,
15.8, IR (CHCl3, cm−1): 3238, 2952, 2926, 1741, 1457, 1383, 1232,
916. Elemental analysis calcd. for C, 60.92; H, 9.27; N, 4.44; S, 10.16.
Found: 60.58; H, 9.42; N, 4.44; S, 10.28.
ppm): δ = 7.32 (bs, 1H), 5.64–5.74 (m, 2H), 5.45–5.50 (m, 1H), 4.60 (m,
1H), 0.79–2.35 (m, 28H). 13C NMR (100 MHz, CDCl3, ppm): δ = 130.9,
129.4, 76.3, 47.9, 41.4, 35.2, 33.9, 31.9, 29.9, 28.9, 26.6, 25.9, 25.5,
23.4, 23.2, 22.1, 21.1, 15.8, IR (CHCl3, cm−1): 3239, 2928, 1739, 1456,
1383, 1238, 1173, 918. Elemental analysis calcd. for C, 62.93; H, 9.68;
N, 4.08; S, 9.33. Found: C, 62.58; H, 9.73; N, 4.24; S, 9.48.
2-Isopropyl-5-methylcyclohexyl benzylsulfamate (2c)
2-Isopropyl-5-methylcyclohexyl ((Z)-cyclooct-2-en-1-yl)
sulfamate (2b)
Yield 70% as a colorless liquid. IR (CH2Cl2, cm−1): 3239, 2928, 2868,
Yield 65% as a colorless liquid. IR (CH2Cl2, cm−1): 3465, 2955, 2869,
1630, 1455, 1387, 1290, 1167, 1105, 950; 1H NMR (400 MHz, CDCl3,
ppm): δ = 7.28–7.2 (m, 6H), 4.95–5 (m, 2H), 4.3–4.36 (m, 1H), 0.65–
2.33 (m, 18H). 13C NMR (100 MHz, CDCl3, ppm): δ = 136.6, 128.6,
1739, 1456, 1383, 1238, 1173, 1058, 918; 1H NMR (400 MHz, CDCl3,
SCHEME 4 General procedure for the synthesis of menthol sulfamate compounds

DARYADEL ET AL.
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128.4, 128.5, 128.0, 83.7, 68.7, 47.9, 41.6, 34.1, 31.6, 25.4, 23.2, 22.2,
21.2, 15.9. Elemental analysis calcd. for C, 62.74; H, 8.36; N, 4.30; S,
9.85. Found: C, 62.56; H, 8.42; N, 4.54; S, 9.76.
4.2 Biochemical studies
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4.2.1 Cholinesterases activity tests
Inhibitory activities of tested novel compounds against AChE and
BChE were measured by slightly modified spectrophotometric
method, developed by Ellman et al.[38] as described previously.[39]
Acetylthiocholine iodide and butyrylthiocholine iodide were used as
substrates of the reaction and 5,5′-dithio-bis(2-nitro-benzoic)acid
(DTNB) method was used for the measurement of the anti-ChE
activity. One hundred thirty microliter of 100 mM sodium phosphate
buffer (pH 8.0), test compound solutions and of solution of AChE or
BChE were mixed and incubated for 15 min at 25°C, and 0.5 mM
DTNB was added.[40] The reaction was then initiated by the addition of
acetylthiocholine iodide (0.71 mM) or butyrylthiocholine chloride
(0.2 mM). The hydrolysis of these substrates was monitored spectro-
photometrically by the formation of yellow 5-thio-2-nitrobenzoate
anion as a result of the reaction of DTNB with thiocholine, released by
the enzymatic hydrolysis of acetylthiocholine iodide or butyrylthiocho-
line chloride, at a wavelength of 412 nm.[41–43] AChE enzyme obtained
from Electrophorus electricus (C3389) and BChE enzyme obtained from
Equus caballus (C4290) were supplied from market. Tacrine was used
as standard compound. Percentage of inhibition of AChE or BChE was
determined by a comparison of the rates of reaction of samples relative
to blank sample (ethanol in phosphate buffer pH 8.0) using the
following formula:
2-Isopropyl-5-methylcyclohexyl (1-phenylethyl)sulfamate (2d)
Yield 68% as a colorless liquid. IR (CH2Cl2, cm−1): 3243, 2957, 2924,
2873, 1745, 1455, 1377, 1172, 914; 1H NMR (400 MHz, CDCl3, ppm):
δ = 7.63–7.64 (m, 1H), 7.28–7.37 (m, 4H), 5.88–5.91 (m, 1H), 4.52–
4.59 (m, 1H), 0.7–2.27 (m, 21H). 13C NMR (100 MHz, CDCl3, ppm):
δ = 128.9, 128.8, 128.7, 126.5, 126.4, 88.0, 76.3, 47.8, 41.3, 33.8, 31.8,
25.5, 23.1, 22.2, 22.1, 21.1, 15.6. Elemental analysis calcd. for C, 63.68;
H, 8.61; N, 4.13; S, 9.44. Found: C, 63.74; H, 8.66; N, 4.22; S, 9.54.
2-Isopropyl-5-methylcyclohexyl benzhydrylsulfamate (2e)
Yield 70% as a colorless liquid. IR (CH2Cl2, cm−1): 3247, 2966, 2934,
2855, 1767, 1476, 1367, 1178, 918; 1H NMR (400 MHz, CDCl3, ppm):
δ = 7.22–737 (m, 10H), 5.71–5.73 (d, 1H), 4.93–4.95 (d, J = .02 Hz, 1H),
4.35–4.36 (m, 1H), 0.68–2.16 (m, 18H). 13C NMR (100 MHz, CDCl3,
ppm): δ = 128.9, 128.8, 128.1, 127.7, 127.6, 84.3, 62.2, 47.7, 41.6,
33.4, 31.7, 29.9, 25.6, 23.2, 22.1, 21.1, 15.8. Elemental analysis calcd.
for C, 68.79; H, 7.78; N, 3.49; S, 7.98. Found: C, 68.57; H, 7.65; N, 3.62;
S, 7.64.
2-Isopropyl-5-methylcyclohexyl (((3-methylbut-2-en-1-yl)oxy)-
carbonyl)sulfamate (2f)
Yield 72% as a colorless liquid. IR (CH2Cl2, cm−1): 3432, 2952, 2924,
1741, 1638, 1459, 1173, 1093, 918; 1H NMR (400 MHz, CDCl3, ppm):
δ = 8.27 (bs, 1H), 5.32–5.36 (m, 1H), 4.67 (d, J = 8.8 Hz, 1H), 4.53–4.60
(m, 1H), 0.78–2.33 (m, 25H). 13C NMR (100 MHz, CDCl3, ppm):
δ = 157.7, 141.0, 117.7, 87.7, 64.2, 47.8, 41.4, 33.9, 31.9, 26.0, 25.5,
23.3, 23.1, 22.1, 21.1, 15.7. Elemental analysis calcd. for C, 55.31; H,
8.41; N, 4.03; S, 9.23. Found: C, 55.24; H, 8.53; N, 4.41; S, 9.38.
½ðE ꢀ SÞ=Eꢁ ꢂ 100
where E is the activity of enzyme without test sample, and S is the
activity of enzyme with test sample.[44–46] The anti-ChE activity of the
novel menthol sulfamate (2a–e) and menthol carbonyl sulfamate (2f–h)
derivatives were measured at different concentrations (from 10−8 to
200 μM) for calculation of the IC50 values. Each substance was tested
three times in triplicate against AChE and BChE enzymes.[47,48]
2-Isopropyl-5-methylcyclohexyl ((but-3-en-2-yloxy)carbonyl)-
sulfamate (2g)
Yield 73% as a colorless liquid. IR (CH2Cl2, cm−1): 3484, 2952, 2927,
1738, 1647, 1460, 1376, 1289, 1174, 1174, 1039, 915; 1H NMR
(400 MHz, CDCl3, ppm): δ = 7.64 (bs, 1H), 5.79–5.87 (m, 1H), 5.18–
5.37 (m, 2H), 4.56–4.62 (m, 1H), 0.77–2.33 (m, 22H). 13C NMR
(100 MHz, CDCl3, ppm): δ = 149.6, 136.5, 117.5, 87.9, 75.0, 47.8, 41.4,
33.8, 31.9, 25.5, 23.2, 22.1, 21.1, 20.1, 15.8. Elemental analysis calcd.
for C, 54.03; H, 8.16; N, 4.20; S, 9.61. Found: C, 54.32; H, 8.07; N, 4.43;
S, 9.54.
|
4.2.2 hCA isoenzyme purification and inhibition
studies
For the investigation of inhibitory effects of novel menthol sulfamate
(2a–e) and menthol carbonyl sulfamate (2f–h) derivative on hCA
isoformes, both hCA isoforms from human erythrocytes were purified
via a simple single-step method by Sepharose-4B-L-tyrosine-sulf-
anilamide affinity gel chromatography.[49–52] For this purpose, the
human erythrocyte samples were centrifuged at 13000 rpm for
25 min. Then the solution was filtered to remove precipitate.[53]
Both hCA isoenzymes were isolated from the serum, which the pH was
adjusted to 8.7 by adding solid Tris. Affinity column was equilibrated by
buffer solution (25 mM Tris-HCl/0.1 M Na2SO4) at pH 8.7. The serum
was loaded to affinity gel and washed with buffer solution (25 mM Tris-
HCl/22 mM Na2SO4) at pH 8.7.[54,55] The hCA I isoenzyme was eluted
by buffer solution (1.0 M NaCl/0.25 M sodium phosphate) at pH 6.3.
On the other hand, hCA II isoenzyme was eluted by another buffer
2-Isopropyl-5-methylcyclohexyl ((allyloxy)carbonyl)sulfamate
(2h)
Yield 68% as a colorless liquid. IR (CH2Cl2, cm−1): 3468, 2956, 2871, 1739,
1648, 1459, 1385, 1229, 1170, 912; 1H NMR (400 MHz, CDCl3, ppm):
5.86–5.96 (m, 1H), 5.38–5.4 (m, 1H), 5.27–5.36 (m, 1H), 4.67–4.68 (m,
2H), 4.55–4.62 (m, 1H), 0.78–2.35 (m, 19H). 13C NMR (100 MHz, CDCl3,
ppm): δ = 150.1, 131.1, 119.9, 87.9, 67.9, 47.9, 41.4, 33.9, 31.9, 23.3, 23.2,
22.1, 21.1, 15.8. Elemental analysis calcd. for C, 52.64; H, 7.89; N, 4.39; S,
10.04. Found: C, 52.57; H, 7.97; N, 4.16; S, 10.23.

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DARYADEL ET AL.
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solution (0.1 M sodium acetate/0.5 M NaClO4) at pH 5.6.[56–59] Both
isoenzymes were taken from the column in fractions of 2 mL. All works
were realized at 4°C. The hCA isoenzymes activity was measured
by following the change at absorbance a specific (348 nm) of
p-nitrophenylacetate (PNA) to p-nitrophenolate ion over a period of
3 min at room temperature (25°C) using a spectrophotometer (Thermo
Scientific, UV-Vis spectrophotometer) according to the method of
Verpoorte et al.[60] as described previously.[61–63] There were 0.4 mL
Tris-SO4 buffer (0.05 M, pH 7.4), 0.3 mL of 3 mM PNA, 0.2 mL of H2O,
and 0.1 mL of enzyme solution in a test tube content of this
reaction.[64–66] Esterase activity assays were identified from a series
of experiments at three different novel menthol sulfamate (2a–e) and
menthol carbonyl sulfamate (2f–h) derivatives.
[16] I. Gulcin, A. Scozzafava, C. T. Supuran, Z. Koksal, F. Turkan,
S. Çetinkaya, Z. Bingöl, Z. Huyut, S. H. Alwasel, J. Enzyme Inhib.
Med. Chem. 2016, 31(6), 1698.
[17] Ç. Bayrak, P. Taslimi, İ. Gülçin, A. Menzek, Bioorg. Chem. 2017,
72, 359.
[18] A. Aktaş, P. Taslimi, İ. Gülçin, Y. Gök, Arch. Pharm. 2017, 350,
e1700045.
[19] P. Taslimi, A. Sujayev, E. Garibov, N. Nazarov, Z. Huyut, S. H. Alwasel,
İ. Gülçin, J. Biochem. Mol. Toxicol. 2017, 31(7), e21897.
[20] N. Öztaskın, P. Taslimi, A. Maras, S. Göksu, İ. Gülçin, Bioorg. Chem.
2017, 74, 104.
[21] P. Taslimi, S. Osmanova, İ. Gulçin, S. Sardarova, V. Farzaliyev,
A. Sujayev, R. Kaya, F. Koc, S. Beydemir, S. H. Alwasel, O. I.
Kufrevioglu, J. Biochem. Mol. Toxicol. 2017, 31(9), e21931.
[22] A. Sujayev, E. Garibov, P. Taslimi, İ. Gülçin, S. Gojayeva, V. Farzaliyev,
S. H. Alwasel, C. T. Supuran, J. Enzyme Inhib. Med. Chem. 2016,
31(6), 1531.
[23] U. Atmaca, A. Yıldırım, S. Tuncel Çelik, İ. Gulçin, C. T. Supuran,
ACKNOWLEDGMENT
M. Çelik, J. Biochem. Mol. Toxicol. 2018, 32(3), e22173.
[24] H. Genç, R. Kalin, Z. Köksal, N. Sadeghian, U. M. Kocyigit, M. Zengin,
İ. Gülçin, H. Özdemir, Int. J. Mol. Sci. 2016, 17, 1736.
[25] B. Turan, K. Sendil, E. Sengul, M. S. Gultekin, P. Taslimi, İ. Gulcin,
C. T. Supuran, J. Enzyme Inhib. Med. Chem. 2016, 31(S1), 79.
[26] H. İ. Gül, K. Kucukoglu, C. Yamali, S. Bilginer, H. Yuca, İ. Ozturk,
P. Taslimi, İ. Gülçin, C. T. Supuran, J. Enzyme Inhib. Med. Chem. 2016,
31(4), 568.
Financial support from the TUBİTAK (113Z700) is gratefully
acknowledged.
CONFLICT OF INTEREST
The authors declare that they have no conflict of interest.
[27] H. I. Gul, E. Mete, P. Taslimi, I. Gulcin, C. T. Supuran, J. Enzyme Inhib.
Med. Chem. 2017, 32, 189.
[28] F. Ozbey, P. Taslimi, I. Gulcin, A. Maraş, S. Goksu, C. T. Supuran,
J. Enzyme Inhib. Med. Chem. 2016, 31, 79.
ORCID
[29] E. Garibov, P. Taslimi, A. Sujayev, Z. Bingöl, S. Çetinkaya, İ. Gulcin,
S. Beydemir, V. Farzaliyev, S. H. Alwasel, C. T. Supuran, J. Enzyme
Inhib. Med. Chem. 2016, 31, 1.
Murat Çelik
http://orcid.org/0000-0003-3485-7822
[30] K. Aksu, B. Özgeris, P. Taslimi, A. Naderi, İ. Gülçin, S. Göksu, Arch.
Pharm. 2016, 349, 944.
REFERENCES
[31] M. Topal, İ. Gülçin, Turk. J. Chem. 2014, 38(5), 894.
[32] H. I. Gul, A. Demirtas, G. Ucar, P. Taslimi, İ. Gülçin, Lett. Drug Des.
Discov. 2017, 14, 573.
[1] C. T. Supuran, A. Scozzafava, Expert Opin. Ther. Pat. 2000, 10, 575.
[2] İ. Gulcin, P. Taslimi, Expert Opin. Ther. Pat. 2018, 28(7), 541.
̧
[33] P. Taslimi, C. Caglayan, İ. Gulçin, J. Biochem. Mol. Toxicol. 2017, 31(12),
e21995.
[3] H. Yamamoto, E. Ho, I. Sasaki, M. Mitsutake, Y. Takagi, H. Imagawa,
M. Nishizawa, Eur. J. Org. Chem. 2011, 13, 2417.
[34] P. Taslimi, H. Akıncıoğlu, İ. Gulçin, J. Biochem. Mol. Toxicol. 2017,
31(11), e21973.
[4] R. Eccles, J. Pharm. Pharmacol. 1994, 46, 618.
[5] I. A. Freires, C. Denny, B. Benso, S. M. de Alencar, P. L. Rosalen,
Molecules 2015, 20, 7329.
[35] P. Taslimi, İ. Gulcin, B. Ozgeris, S. Goksu, F. Tumer, S. H. Alwasel, C. T.
Supuran, J. Enzyme Inhib. Med. Chem. 2016, 31, 152.
[6] B. Yiğit, M. Yiğit, D. Barut Celepci, Y. Gök, A. Aktaş, M. Aygün,
̈
[36] P. Taslimi, İ. Gu
C. T. Supuran, J. Enzyme Inhib. Med. Chem. 2016, 31(4), 603.
̈lçin, N. Oztaşkın, Y. Çetinkaya, S. Goksu, S. H. Alwasel,
̈
P. Taslimi, İ. Gulçin, ChemistrySelect 2018, 3(27), 7976.
[7] S. B. Öztürk Sarıkaya, F. Topal, M. Şentürk, İ. Gülçin, C. T. Supuran,
Bioorg. Med. Chem. Lett. 2011, 21, 4259.
[37] U. M. Koçyiğit, Y. Budak, F. Eligüzel, P. Taslimi, D. Kılıç, İ. Gulc
̧in,
M. Ceylan, Arch. Pharm. 2017, 350, e1700198.
[8] P. Taslimi, İ. Gulçin, J. Food Biochem. 2018, 42(3), e12516.
[9] P. Taslimi, C. Çağlayan, F. Farzaliyev, F. Turkan, O. Nabiyev,
A. Sujayev, F. Türkan, R. Kaya, İ. Gulçin, J. Biochem. Mol. Toxicol.
2018, 32(4), e22042.
[38] G. L. Ellman, K. D. Courtney, V. Andres, R. M. Featherston, Biochem.
Pharmacol. 1961, 7, 88.
[39] İ. Gulçin, M. Abbasova, P. Taslimi, Z. Huyut, L. Safarova, A. Sujayev,
V. Farzaliyev, S. Beydemir, S. H. Alwasel, C. T. Supuran, J. Enzyme
Inhib. Med. Chem. 2017, 32, 1174.
[10] F. Turkan, Z. Huyut, P. Taslimi, İ. Gulçin, J. Biochem. Mol. Toxicol. 2018,
32(3), e22041.
[40] F. Erdemir, D. Barut Celepci, A. Aktaş, P. Taslimi, Y. Gök, H. Karabıyık,
[11] C. Yamali, H. İ. Gül, A. Ece, P. Taslimi, İ. Gulçin, Chem. Biol. Drug Des.
2018, 91, 854.
İ. Gulc
[41] T. Daştan, U. M. Koçyiğit, S. Durna Daştan, C. Kiliçkaya, P. Taslimi,
Ç. Özge, M. Koparir, A. Çetin, C. Orek, İ. Gulcin, J. Biochem. Mol.
Toxicol. 2017, 31, e21971.
̧in, J. Mol. Struct. 2018, 1155, 797.
[12] P. Taslimi, E. Sujayev, F. Turkan, E. Garibov, Z. Huyut, F. Farzaliyev, S.
Mamedova, İ. Gulçin, J. Biochem. Mol. Toxicol. 2018, 32(2), e22019.
[13] U. M. Koçyiğit, Y. Budak, M. B. Gürdere, F. Ertürk, B. Yencilek,
̧
[42] U. M. Koçyiğit, A. Taşkıran, P. Taslimi, A. Yokuş, Y. Temel, İ. Gulçin,
J. Biochem. Mol. Toxicol. 2017, 31, e21972.
P. Taslimi, İ. Gulçin, M. Ceylan, Arch. Physiol. Biochem. 2018, 124, 61.
[14] S. Burmaoglu, A. O. Yilmaz, P. Taslimi, O. Algul, D. Kılıç, İ. Gulçin, Arch.
Pharm. 2018, 351(2), e1700314.
[43] B. Arabaci, İ. Gülçin, S. Alwasel, Molecules 2014, 19, 10103.
[44] M. Isik, Y. Demir, M. Kirici, R. Demir, F. Simsek, S. Beydemir, Arch.
Physiol. Biochem. 2015, 121, 97.
[15] I. Gulcin, A. Scozzafava, CT. Supuran, H. Akıncıoğlu, Z. Koksal,
F. Turkan, S. Alwasel, J. Enzyme Inhib. Med. Chem. 2016, 31(6), 1095.

DARYADEL ET AL.
9 of 9
|
[45] İ. Gulc
̧
in, P. Taslimi, A. Aygün, N. Sadeghian, E. Bastem, Ö. İ.
[60] J. A. Verpoorte, S. Mehta, J. T. Edsall, J. Biol. Chem. 1967, 242,
4221.
Küfrevioğlu, F. Turkan, F. Şen, Int. J. Biol. Macromol. 2018, 119, 741.
[46] H. İ. Gül, M. Tuğrak, H. Sakagami, P. Taslimi, İ. Gülçin, C. T. Supuran,
J. Enzyme Inhib. Med. Chem. 2016, 31(6), 1619.
[61] B. Özgeriş, S. Göksu, L. Köse Polat, İ. Gülçin, R. E. Salmas, S. Durdagi,
F. Tümer, C. T. Supuran, Bioorg. Med. Chem. 2016, 24(10), 2318.
[62] M. Küçük, İ. Gulcin, Environ. Toxicol. Pharmacol. 2016, 44, 134.
[63] A. Akıncıoğlu, H. Akıncıoğlu, I. Gülçin, S. Durdağı, C. T. Supuran,
S. Göksu, Bioorg. Med. Chem. 2015, 23(13), 3592.
[47] A. Behcet, T. Çağlılar, D. Barut Celepci, A. Aktaş, P. Taslimi, Y. Gök,
M. Aygün, R. Kaya, İ. Gulçin, J. Mol. Struct. 2018, 1170, 160.
[48] A. Akıncıoğlu, E. Kocaman, H. Akıncıoğlu, R. E. Salmas, S. Durdağı,
İ. Gülçin, C. T. Supuran, S. Göksu, Bioorg. Chem. 2017, 74, 238.
[49] Y. Çetinkaya, H. Göçer, S. Göksu, İ. Gülçin, J. Enzyme Inhib. Med. Chem.
2014, 29(2), 168.
[64] Z. Huyut, Ş. Beydemir, İ. Gulcin, J. Biochem. Mol. Toxicol. 2017, 31(9),
e21930.
[65] C. Caglayan, I. Gulçin, J. Biochem. Mol. Toxicol. 2018, 32(1), e22010.
[50] A. Akıncıoğlu, M. Topal, İ. Gülçin, S. Göksu, Arch. Pharm. 2014, 347(1), 68.
[51] Y. Çetinkaya, H. Göçer, İ. Gülçin, A. Menzek, Arch. Pharm. 2014,
347(5), 354.
[66] M. Rezai, Ç. Bayrak, P. Taslimi, İ. Gulc
̧in, A. Menzek, Turk. J. Chem.
2018, 42(3), 808.
[52] S. Göksu, A. Naderi, Y. Akbaba, P. Kalın, A. Akıncıoğlu, İ. Gulcin,
S. Durdaği, R. E. Salmas, Bioorg. Chem. 2014, 56, 75.
[53] Y. Akbaba, E. Bastem, F. Topal, İ. Gülçin, A. Maraş, S. Göksu, Arch.
Pharm. 2014, 347(12), 950.
SUPPORTING INFORMATION
Additional supporting information may be found online in the
Supporting Information section at the end of the article.
[54] H. Göçer, A. Akıncıoğlu, S. Göksu, İ. Gülçin, C. T. Supuran, J. Enzyme
Inhib. Med. Chem. 2015, 30(2), 316.
[55] A. Scozzafava, M. Passaponti, C. T. Supuran, İ. Gülçin, J. Enzyme Inhib.
Med. Chem. 2015, 30(4), 586.
[56] M. Boztaş, Y. Çetinkaya, M. Topal, İ. Gülçin, A. Menzek, E. Şahin,
M. Tanc, C. T. Supuran, J. Med. Chem. 2015, 58(2), 640.
[57] A. Yıldırım, U. Atmaca, A. Keskin, M. Topal, M. Çelik, İ. Gülçin,
C. T. Supuran, Bioorg. Med. Chem. 2015, 23(10), 2598.
[58] A. Akıncıoğlu, H. Akıncıoğlu, I. Gülçin, S. Durdağı, C. T. Supuran,
S. Göksu, Bioorg. Med. Chem. 2015, 23(13), 3592.
How to cite this article: Daryadel S, Atmaca U, Taslimi P,
Gülçin İ, Çelik M. Novel sulfamate derivatives of menthol:
Synthesis, characterization, and cholinesterases and carbonic
anhydrase enzymes inhibition properties. Arch Pharm Chem
Life Sci. 2018;1–9. https://doi.org/10.1002/ardp.201800209
[59] H. Gocer, A. Aslan, İ. Gülçin, C. T. Supuran, J. Enzyme Inhib. Med. Chem.
2016, 31(3), 503.