Synthesis, characterization, stereochemistry and biological evaluation of novel cyclohexanol derivatives

Article abstract of DOI:10.14233/ajchem.2018.21202

This research includes the synthesis of 1,5-diketone from chalcone by Michael addition of p-chloroacetophenone in the presence of NaOH (molar ratio, 1:1:10), which led to the formation of a novel cyclohexanol derivative as a side product. The above reaction was repeated with different molar ratio of chalcone-acetophenone-sodium hydroxide to set the optimum condition for maximum yield of the novel cyclohexanol derivative. The dehydration of cyclohexanol using catalytic amount of p-TsOH produced quantitative yield of corresponding cyclohexene with β,γ-unsaturation instead of apparently more stable α,β-unsaturation. The compounds were well characterized by spectroscopic techniques and elemental analysis. Their stereochemistry is discussed and newly synthesized compounds are screened for anticancer and antimicrobial activities.

Full text of DOI:10.14233/ajchem.2018.21202

Asian Journal of Chemistry; Vol. 30, No. 5 (2018), 1102-1108
A
SIAN
J
OURNAL OF HEMISTRY
C
https://doi.org/10.14233/ajchem.2018.21202
Synthesis, Characterization, Stereochemistry and Biological
Evaluation of Novel Cyclohexanol Derivatives
*
SAYEED MUKHTAR , MESHARI A. ALSHARIF, MOHAMMED I. ALAHMDI and HUMAIRA PARVEEN
Department of Chemistry, Faculty of Science, University of Tabuk, Tabuk-71491, Kingdom of Saudi Arabia
*
Corresponding author: E-mail: sayeed_mukhtar@hotmail.com
Received: 26 December 2017; Accepted: 18 February 2018;
Published online: 29 March 2018;
AJC-18849
This research includes the synthesis of 1,5-diketone from chalcone by Michael addition of p-chloroacetophenone in the presence of
NaOH (molar ratio, 1:1:10), which led to the formation of a novel cyclohexanol derivative as a side product. The above reaction was
repeated with different molar ratio of chalcone-acetophenone-sodium hydroxide to set the optimum condition for maximum yield of the
novel cyclohexanol derivative. The dehydration of cyclohexanol using catalytic amount of p-TsOH produced quantitative yield of
corresponding cyclohexene with β,γ-unsaturation instead of apparently more stable α,β-unsaturation. The compounds were well
characterized by spectroscopic techniques and elemental analysis. Their stereochemistry is discussed and newly synthesized compounds
are screened for anticancer and antimicrobial activities.
Keywords: Chalcones, Cyclohexanol derivatives, Stereochemistry, in vitro Anticancer activity, in vitro Antimicrobial activity.
in a Ribermag R10-10B quadrupole mass spectrometer. Column
chromatography was performed on silica gel (60-120 mesh).
INTRODUCTION
Recently, a considerable amount of research on biolog-
4
'-Chloro-4-methoxychalcone (1a) and 4,4'-dichloro-
ically active cyclohexanol derivatives has been reported [1-6]
and has attracted growing interest of medicinal chemists. An
elaborative literature survey on cyclohexanol derivatives has
revealed that they exhibited diverse biological activities such
as acetylcholine-storage-blocking activities [7], analgesic [8],
antidepressant [9], cardio-inhibitory effects [10] and also have
been reported as potent microbial agents [11].
chalcone (1b) were synthesized according to the published
method [19].
General procedure for the synthesis of 1,5-diketones
and cyclohexanol derivatives: A mixture of chalcone (1a)
(
500 mg, 1.83 mmol), p-chloroacetophenone (0.24 mL, 283
mg, 1.83 mmol) in an aqueous ethanolic solution of NaOH
7 mL, H O-EtOH, 1:1) (734 mg, 18.3 mmol) was heated on a
(
2
In view of these observations and as part of our program
in search of biologically active compounds with sulphur and
nitrogen containing heterocycles [12-18], we report here the
synthesis, characterization, stereochemistry, anticancer and
antimicrobial studies of cyclohexanol derivatives.
water bath for 5 h monitoring the progress of the reaction by
TLC at every 15 min. After completion, the reaction mixture
was extracted with ethyl acetate, washed with water and the
organic phase dried over Na
2
SO . The solvent was distilled
4
off under reduced pressure to a semi-solid residue which on
column chromatography (silica gel, petroleum ether (60-80 ºC)-
EXPERIMENTAL
diethyl ether, 6:4 v/v) followed by crystallization from C
6
H -EtOAc
6
Reagents and solvents were of commercial grade and used
without further purification. Melting points were determined
on a Koffler hot-plate apparatus and are uncorrected. Elemental
analysis (C, H, N) were undertaken using an Elemental analyzer
and within ± 0.4 ꢀ of the calculated values. IR spectra were
yielded compounds 2a and 3a as white crystalline needles.
1,5-Bis(4-chlorophenyl)-3-(4-methoxyphenyl)pentan-
1,5-dione (2a): Yield: 68ꢀ; m.p 80 ºC, R 0.67 (benzene-
f
-1
diethyl ether, 9.5:0.5 v/v). IR (KBr, cm ): 1675 ν(C=O), 1610,
1580 ν(phenyl), 1510, 1400, 1350, 1250, 1170, 1075, 980,
1
1
recorded on a Perkin-Elmer 621 spectrophotometer while H
810; H NMR (400 MHz, acetone-d
6
): δ 3.41 (dd, 2H, H-2up/
13
and C NMR spectra were recorded on aVarian Unity 400 spectro-
meter at 400 MHz and 100 MHz, respectively in acetone-d
withTMS as the internal standard. DCI-mass spectrawere recorded
4up, J = 16.94 Hz, J = 7.48 Hz); 3.51 (dd, 2H, H-2dn/4dn, J =
16.94 Hz, J = 6.56 Hz); 3.98 (br p, 1H, H-3, J ≈ 7 Hz); 3.70 (s,
6
3H, H-OCH ); 7.25 (d, 2H, H-Ar′-2,6, J = 8.85 Hz); 6.78 (d, 2H,
3

Vol. 30, No. 5 (2018)
Synthesis, Stereochemistry and Biological Evaluation of Novel Cyclohexanol Derivatives 1103
H-Ar′-3,5, J = 8.85 Hz); 7.98 (d, 4H, H-Ar-2, 6, J = 8.85 Hz);
2,6) 129.11 (C-Ar′-3,5), 130.64 (C-Ar-2,6), 129.64 (C-Ar-3,5),
132.44 (C-Ar′-1), 144.20 (C-Ar′-4), 136.74 (C-Ar-1), 139.60
13
7
.49 (d, 4H, H-Ar-3,5, J= 8.85 Hz); C NMR (100 MHz, acetone-
): δ 45.70 (C-2/4), 37.25(C-3), 55.42 (C-OCH ) 129.51 (C-
Ar′-2,6), 114.57 (C-Ar′-3,5), 130.62 (C-Ar-2,6), 129.57 (C-Ar-
,5), 136.96 (C-Ar′-1), 159.27 (C-Ar′-4), 136.86 (C-Ar-1), 139.45
d
6
3
(C-Ar-4), 197.77 (C-CO); MS (DCI): m/z 427/429/431/433
+
(M +1); Anal. Calcd for C23
Found: C, 63.89; H, 3.96 ꢀ.
H
17
O
2
Cl : C, 63.98; H, 3.97 ꢀ.
3
3
+
(
C-Ar-4), 198.06(C-CO), MS (DCI): 431/433/435 (M + 1);
Anal. Calcd for C24 Cl : C, 67.46; H, 4.72 ꢀ; Found: C,
7.39; H, 4.70 ꢀ.
,4-Bis(4-chlorobenzoyl)-1-(4-chlorophenyl)-3,5-bis(4-
methoxyphenyl)cyclohexan-1-ol (3a):Yield: 6.6 ꢀ, m.p. 232
2,4-Bis(4-chlorobenzoyl)-1,3,5-tris(4-chlorophenyl)-
cyclohexan-1-ol (3b): Yield: 7.3 ꢀ; m.p. 242 ºC, R 0.67
H
20
O
3
2
f
-1
6
(benzene-diethyl ether 9.5:0.5 v/v); IR (KBr, cm ): 3475 ν(OH),
2
1665, 1645 ν(C=O), 1610, 1580 ν(phenyl), 1510, 1395, 1260,
1
1175, 1085, 1015, 820 cm. H NMR (400 MHz, acetone-d
6
):
-1
ºC, R
f
0.42 (benzene-diethyl ether, 9.5:0.5 v/v). IR (KBr, cm ):
480 ν(OH); 1665, 1640 ν(C=O); 1610, 1585 ν(phenyl), 1510,
400, 1250, 1175, 1085, 1025, 1005, 820. The δ and δ values
2.00 (dd, 1H, H-6eq, J = 3.66 Hz, J = 13.74 Hz), 2.86 (br dt, 1H,
H-6ax, J= 2.29 Hz, J= 11-12 Hz, J= 13.74 Hz), 3.92 (br dt, 1H, H-5ax
3
1
,
H
C
J ≈ 11.10 Hz, J = 11-12 Hz, J = 3.66 Hz), 4.12 (br t, 1H, H-3ax
J ≈ 11.45); 4.82 (br t, 1H, H-4ax, J ≈ 11.14), 5.16 (d, 1H, H-2ax
,
,
are given in Tables 1 and 2. MS (ApcI): m/z 681/683/685/687
+
+
[
M + 1−H
2
O] .
J = 11.60 Hz); 5.12 (d, H, H-OH, J = 2.29 Hz); 6.91-7.73 (br m,
13
The above reaction was also carried out with different
H-5 ×Ar-rings). C NMR (100 MHz, acetone-d ): 46.51 (C-6),
6
molar ratios of chalcone 1a and acetophenone in the presence
of 10 equiv. NaOH (10 ꢀ) as described above which furnished
compounds 2a and 3a in varying yields.
44.22 (C-5), 48.47 (C-3), 55.50a (C-4), 56.08 (C-2), 76.11 (C-1),
202.34 (C-CO), 205.33 (C-CO), 127.84-146.28 (C-5 ×Ar-rings).
+
+
MS (ApcI): m/z 689/691/693/695 [M +1−H O] .
2
Further, Michael reaction of chalcone 1a with the isolated
General procedure for the synthesis of 4,6-bis(4-chloro-
benzoyl)-1-(4-chlorophenyl)-3,5-bis(4-methoxyphenyl)-
cyclohexene (4a):To a solution of compound 3a (100mg, 0.142
mmol) in dry benzene (5 mL) was added p-toluene sulphonic
acid (5 mg) and refluxed with stirring over an oil bath at 80 ºC
for 3 h. The reaction mixture was cooled, washed with water and
1
,5-diketone 2a was also conducted as follows: A mixture of
chalcone 1a (400 mg, 1.46 mmol) and 1,5-diketone 2a (500
mg, 1.17 mmol) in NaOH solution (5.0 mL, H O-EtOH, 1:1)
470 mg, 11.7 mmol) was heated on a water bath for 5 h. The
2
(
products on usual workup and crystallization afforded
compound 3a as white crystalline globules, 570 mg (69.6 ꢀ),
the organic phase dried over Na
off under reduced pressure and the residue left on usual workup
and crystallization from C -EtOAc afforded compound 4a as
white crystalline globules, 91 mg (93.4 ꢀ), m. p 218 ºC, R 0.60
(benzene:diethyl ether, 9.5:0.5 v/v). IR (KBr, cm ): 2835 ν(C-H),
1668 ν(C=O), 1613, 1587, 1569 ν(phenyl), 1512,1488, 1462,
1440, 1399, 1305, 1287, 1254 1214, 1179, 1092, 1031, 1011, 971,
2
SO
4
. The solvent was distilled
m.p. 232 ºC, R
,3,5-Tris(4-chlorophenyl)pentan-1,5-dione (2b):Yield:
2 ꢀ; m.p 110 ºC, R 0.85 (benzene-diethyl ether 9.5:0.5 v/v); IR
KBr, cm ): 1680 ν(C=O), 1610, 1585 ν(phenyl), 1520, 1400,
f
0.42 (benzene-diethyl ether, 9.5:0.5 v/v).
1
6 6
H
7
(
f
f
-1
-1
1
1
350, 1260, 1165, 1060, 980, 810. H NMR (400 MHz, acetone-
d
6
): 3.49 (dd, 2H, H-2up/4up, J = 17.24 Hz, J = 7.63 Hz); 3.59
(
1
(
8
dd, 2H, H-2dn/4dn, J = 17.24 Hz, J = 6.41 Hz); 4.05 (br p,
H, H-3, J ≈ 7 Hz); 7.26 (d, 2H, H-Ar′-2,6, J = 8.54 Hz); 7.40
d, 2H, H-Ar′-3,5, J = 8.54 Hz); 8.00 (d, 4H, H-Ar-2,6, J =
862, 830, 751, 729, 697. The δ
are given in Table-3. MS (ApcI): m/z 681/683/685/687 (M +1).
4-Bis(4-chlorobenzoyl)-1,3,5-tris(4-chlorophenyl)-
cyclohexene (4b):Yield: 94.6ꢀ; m.p. 254 ºC, R
diethyl ether 9.5:0.5 v/v); IR (KBr, cm ): 2858 ν(C-H), 1668
H
and δ values of compound 4a
C
+
13
.70 Hz); 7.52 (d, 4H, H-Ar-3,5, J = 8.70 Hz). C NMR (100
f
0.90 (benzene-
-1
MHz, acetone-d ): 45.29 (C-2/4), 37.23 (C-3), 130.48 (C-Ar′-
6
TABLE-1
H NMR DATA OF 3a IN ACETONE-d6
1
H-nr
δ(ppm)
Integration Multiplicity
Dd
J (Hz) + COSY
J5ax,6eq 3.66; J6ax,6eq.13.73
J6ax,OH 2.29; J5ax,6ax 11-12; J6ax,6eq 13.73
6eq
6ax
1.97
2.78
3.86
1H
1H
1H
br dt
br dt
5ax
J4ax,5ax ≈ 11.14; J5ax,6ax
1
1-12; J5ax,6eq 3.66
3ax
4ax
2ax
4.02
4.71
1H
1H
br t
br t
D
D
d
d
s
d
d
s
d
d
d
d
d
d
J2ax,3ax ≈ J3ax,4ax ≈ 11.45
J3ax,4ax ≈ J4ax,5ax ≈ 11.14
J2ax, 3ax 11.75
JOH,6ax 2.29
JAr’-2,6,Ar’-3,5 8.85
JAr’-2,6,Ar’-3,5 8.85
5.08
5.14
7.19
6.42
3.60
7.26
6.66
3.43
7.42
7.15
7.52
7.19
7.71
7.19
1H
1H
2H
2H
3H
2H
2H
3H
2H
2H
2H
2H
2H
2H
1
3
3
3
5
5
5
4
4
2
2
1
1
-OH
-[Ar’-2,6]
-[Ar’-3,5]
-[Ar’-OCH3]
-[Ar’-2,6]
-[Ar’-3,5]
-[Ar’-OCH3]
-Ar-2,6
-Ar-3,5
-Ar-2,6
-Ar-3,5
-Ar-2,6
JAr’-2,6,Ar’-3,5 8.70
JAr’-2,6, Ar’-3,5 8.70
JAr-2,6,Ar-3,5 8.69
JAr-2,6,Ar-3,5 8.69
JAr-2,6,Ar-3,5 8.85
JAr-2,6,Ar-3,5 8.85
JAr-2,6,Ar-3,5 8.69
JAr-2,6,Ar-3,5 8.69
-Ar-3,5

1
104 Mukhtar et al.
Asian J. Chem.
TABLE-2
13
C NMR DATA OF COMPOUND 3a IN ACETONE-d6
C-no.
δ (ppm)
HETCOR correlation with
H-6 ; H-6
H-5ax
H-3ax
H-4ax
H-2ax
Long-range HETCOR correlation with
1-OH
6
5
3
4
2
1
47.03
43.94
48.38
56.45
56.36
76.25
ax
eq
H-2 , H-4
ax
ax
a
a
CO
CO
203.03
205.95
128.84
114.28
159.42
132.16
b
3
3
3
3
3
5
5
5
5
5
4
4
4
4
2
2
2
2
1
1
1
-[Ar-2,6]
-[Ar-3,5]
-[Ar-4]
-[Ar-1]
-[Ar-OCH3]
-[Ar-2,6]
-[Ar-3,5]
-[Ar-4]
-[Ar-1]
-[Ar-OCH3]
-Ar-2,6
-Ar-3,5
-Ar-1
H-{3-[Ar-2,6]}
H-{3-[Ar-3,5]}
H-{3-[Ar’-OCH ]}
3
c
55.39
H-{3-[Ar-OCH ]}
3
129.83
114.62
159.42
133.04
H-{5-[Ar-2,6]}
H-{5-[Ar-3,5]}
H-5ax
H-{5-[Ar’-OCH ]}, H-{5-[Ar’-2,6]}
3
c
55.26
H-{5-[Ar-OCH ]}
3
130.17
128.68
135.53
137.41
130.64
128.94
138.34
138.47
128.84
127.81
139.69
146.73
H-{4-[Ar-2,6]}]
H-{4-[Ar-3,5]}
d
d
-Ar-4
-Ar-2,6
-Ar-3,5
-Ar-1
H-{2-[Ar-2,6]}
H-{2-[Ar-3,5]}
b
d
d
b
b
d
-Ar-4
-Ar-2,6
-Ar-3,5
-Ar-1
H-{1-[Ar-2,6]}
H-{1-[Ar-3,5]}
1
a
-Ar-4
Assignment with the same superscript may be interchanged.
TABLE-3
1
H NMR SPECTRAL DATA OF COMPOUND 4a IN ACETONE-d6
J (Hz) + COSY C-no
J6ax,2, J2,3ax 2.14
J3ax, 4ax ≈ 11.10; J2,3ax 2.14; J3ax,
3.97
H-no
δ (ppm)
6.15
4.16
Integration Multiplicity
δ (ppm)
131.32
47.16
HETCOR
H-2
H-3pseud.ax
2
1H
1H
T
br dq
2
3
3ax
≈
pseud.ax
6
6ax
5.49
1H
br dq
J5ax,6ax ≈ 11.10; J3ax,6ax ≈ 3.97;
J2,6 2.14
6
55.15
H-6pseud.ax
4ax
5ax
4.57
3.74
1H
1H
br t
br t
J5ax,4ax ≈ J3ax,4ax ≈ 11.10
J5ax,6 ≈ J4ax,5ax ≈ 11.10
4
5
53.20
50.42
H-4ax
H-5ax
5
× Ar
6.47-7.74 20H
3.54 3H
br m
s
–
–
CO
CO
204.10
206.83
H-OCH3
5
× Ar
128.32-159.70
(
1
7
C=O), 1589, 1569 ν(phenyl), 1488, 1402, 1360, 1317, 1289,
0.0105 mol) and ammonium carbonate (3.36 g, 0.350 mol) in
dry benzene (30 mL) was refluxed for 28 h, collecting the
generated water in an azeotropic collector. The reaction mixture
was concentrated, extracted with diethyl ether, washed with
water until filtrate was neutral and dried over sodium sulphate
overnight. Evaporation of the solvent afforded a white solid
mass which was recrystallized from acetone-benzene to furnish
compound 7a as white crystals, 1.026 g (87 ꢀ), m.p. 207-208
215, 1175, 1094, 1014, 981, 965, 910, 870, 842, 805, 761, 738,
1
20, 677. H NMR (400 MHz, acetone-d ): 6.17 (t, 1H, H-2eq,
6
J = 2.14 Hz); 4.23 (br dq, 1H, H-3ax, J ≈ 11.14 Hz, J ≈ 2.14 Hz,
J ≈ 3.66 Hz); 3.82 (br t, 1H, H-5ax, J ≈ 11.14 Hz); 4.69 (br t, 1H,
H-4ax, J ≈ 11.14 Hz); 5.56 (br dq, 1H, H-6ax, J ≈ 11.14 Hz, J
≈
2.14 Hz, J ≈ 3.66 Hz); 3.54 (s, 3H, H-OCH
H-OCH ); 6.98-7.70 (br m, 20 H, 2 × H-Ar′ + 3 × H-Ar). C NMR
): 132.49 (C-2), 48.72 (C-3), 54.25 (C-4),
3
); 3.66 (s, 3H,
13
3
(100 MHz, acetone-d
6
ºC, R 0.63 (petroleum ether-diethyl ether, 7:3 v/v); IR (KBr,
f
-1
5
1
(
0.54 (C-5), 55.50 (C-6), 200.70 (C-CO), 202.43 (C-CO),
cm ): 1610 ν(C=N and phenyl), 1590, 1570 ν(phenyl), 1540,
27.80-159.42 (C-5 × Ar); MS (ApcI): m/z 689/691/693/695
1505, 1475, 1420, 1375, 1285, 1245, 1165, 1075, 1000, 820.
+
1
M +1).
H NMR (400 MHz, acetone-d
6
): 3.88 (s, 3H, H-OCH ); 8.15
3
General procedure for the synthesis of 2,6-bis(4-chloro-
phenyl)-4-(4-methoxyphenyl)pyridine (7a): A mixture of
,5-diketone 2a (1.5 g, 0.0035 mol), thioglycollic acid (0.966 g,
(s, 2H, H-3,5); 7.94 (d, 2H, H-Ar′-2,6, J = 8.85 Hz); 7.10 (d, 2H,
H-Ar′-3,5, J = 8.85 Hz); 8.35 (d, 4H, H-2, Ar-2,6, J = 8.69);
7.55 (d, 4H, H-2,Ar-3,5, J= 8.69). C NMR (100 MHz, acetone-
13
1

Vol. 30, No. 5 (2018)
Synthesis, Stereochemistry and Biological Evaluation of Novel Cyclohexanol Derivatives 1105
d
(
1
1
4
6
): 55.82 (C-OCH
C-Ar′-2,6); 115.45 (C-Ar′-3,5), 151.05 (C-4), 131.31 (C-Ar′-
), 161.96 (C-Ar′-4), 129.65 (C-2Ar-2,6), 129.59 (C-2Ar-3,5),
39.13 (C-2 Ar-1), 135.60 (C-2 Ar-4); MS (DCI): 406/408/
3
), 156.86 (C-2,6), 117.24 (C-3,5); 129.48
and filled with 100 µL of compound, solvent blank and an anti-
biotic (chloramphenicol, 100 µg/mL) to which the test bacteria
were sensitive. Fluconozole at the concentration of 100 µg/mL
was used as the control against Candida albicans. The plates
were incubated for 18 h at 37 ºC. Antimicrobial activity was
evaluated by measuring the zone of inhibition against the test
organism.
+
10 (M +1);Anal. Calcd for C24
H
17NOCl : C, 70.95; H, 4.22;
2
N, 3.45 ꢀ. Found: C, 70.88; H, 4.21, N, 3.47 ꢀ.
,4,6-Tris(4-chlorophenyl)pyridine (7b): Yield 89 ꢀ,
m.p. 220-222 ºC, R 0.78 (petroleum ether-diethyl ether, 7:3 v/v);
IR (KBr, cm ): 1620 ν(C=N and phenyl), 1600, 1580 ν(phenyl),
540, 1510, 1480, 1420, 1365, 1250, 1225, 1090, 985, 860, 810.
2
f
-1
RESULTS AND DISCUSSION
1
The aim of the present work was to synthesize dithiazolidin-
1
H NMR (400 MHz, acetone-d
H, H-Ar′-2,6, J = 8.70 Hz); 7.10 (d, 2H, H-Ar′-3,5, J = 8.70
Hz); 8.42 (d, 4H, H-2, Ar-2,6, J = 8.65); 7.60 (d, 4H, H-2, Ar-
6
): 8.22 (s, 2H, H-3,5); 8.06 (d,
4
-one derivatives from chalcones via the formation of 1,5-
2
diketones by Michael addition of acetophenone, using thiogly-
collic acid in the presence of ammonium carbonate. Interestingly,
during the preparation of 1,5-diketones (2a and 2b) from chalcones
13
3
2
1
2
2
,5, J = 8.65); C NMR (100 MHz, acetone-d ): 156.92 (C-
6
,6), 118.70 (C-3,5); 130.52 (C-Ar′-2,6); 116.55 (C-Ar′-3,5),
51.02 (C-4), 129.49 (C-Ar′-1), 147.35 (C-Ar′-4), 130.12 (C-
Ar-2,6), 129.89 (C-2Ar-3,5), 140.08 (C-2Ar-1), 136.22 (C-
(
1a and 1b) by the Michael addition of p-chloroacetophenone
in the presence of NaOH (molar ratio, 1:1:10), a novel cyclo-
hexanol derivative was obtained as a side product (Scheme-I).
+
Ar-4); MS (DCI): m/z 410/412/414 (M +1); Anal. calcd for
C
23
H14NCl
3
: C, 67.26; H, 3.44; N, 3.41ꢀ. Found: C, 67.37; H,
Ar'
O
3
.42; N, 3.40ꢀ.
Ar
Ar'
Ar
NaOH
Ar
Ar
Ar
+
+
HO
Ar
in vitro Anticancer activities: The compounds 3a, 3b and
a have been evaluated in the 3-cell line of three types of
O
O
O
Ar'
O
Ar'
7
Ar
Ar'
Yield
O
Ar
human cancers: breast (MCF7), Lung (NCI-H460) and CNS
SF-268) in the one dose primary anticancer assay at 10 µM
1
1
a: p-Cl-Ph, p-OMe-Ph
b: p-Cl-Ph, p-Cl-Ph
2a: 68.0%
2b: 72.0%
Yield
3a: 6.6%
b: 7.3%
(
3
concentration. In the current protocol, each cell line is inocu-
lated and preincubated on a microtiter plate. Test agents were
then added at a single concentration and the culture incubated
for 48 h. End point determinations were made with alamar
blue [20]. Results for each test agent are reported as the percent
of growth of the treated cells when compared to the untreated
control cells.
Scheme-I: Synthesis of cyclohexanol derivatives (3a and 3b)
It seems that the formation of cyclohexanol in the above
reactions has occurred probably by double Michael addition
23] followed by intramolecular aldol condensation [24] of
[
bis-adduct formed in situ. This was confirmed by carrying out
Michael addition reaction of the isolated 1,5-diketone 2a to
chalcone 1a under the same condition, which yielded
cyclohexanol 4a as the sole product. Keeping in view of the
novelty of the side product, the same reaction was repeated
with different molar ratios of chalcone-acetophenone-sodium
hydroxide to set the optimum condition to obtain maximum
yield of cyclohexanol and thus the ratio was fixed as 2:1:10
in vitro Antimicrobial activities: A total of 4 compounds
(
(
3a, 3b, 4a and 4b) were tested against two Gram +ve bacteria
Staphylococcus aureus, Bacillus substilis) and two Gram -ve
bacteria (Estcherichia coli, Pseudomonas aeruginosa) and a
yeast, Candida albicans. Sabour and dextrose (SD) and
Nutrient broth agar media were obtained from Hi-Media Pvt.
Ltd. (Bombay, India) were used for Canadida albicans and
test bacteria, respectively. Freshly grown microbial cultures
at 37 ºC were appropriately diluted in sterile normal saline
(
Table-4).
The dehydration of cyclohexanols 3a and 3b with catalytic
6
solution to obtain a cell suspension of 10 CFU/mL.
amount of p-TsOH resulted in an unusual stereo selective
synelimination producing quantitative yields of β,γ-unsaturated
cyclohexenes 4a (94.4 ꢀ) and 4b (93.4 ꢀ) instead of apparently
more stable α,β-unsaturated cyclohexenes 5a and 5b (Scheme-
II).
Each synthetic compound was dissolved in DMSO to
obtain a stock solution of different concentration ranging from
2
500 µg/mL. The agar well diffusion method [21,22] was used.
6
0.1 mL of the diluted inoculum (10 CFU/mL) of test organism
was spread on nutrient agar/sabour and dextrose agar plates.
Wells of 8 mm diameter were punctured into the agar medium
This is probably due to the fact that the hydroxyl group in
cyclohexanol being in axial disposition, the elimination went
TABLE-4
YIELDS OF COMPOUNDS 2a AND 3a WITH INCREASE IN MOLAR RATIOS OF CHALCONE-ACETOPHENONE
Chalcone-acetophenone
Products* (ꢀ Yields-Isolated)
Substrate (chalcone)
Time (h)
mmol
Molar ratio
1:1
1.25:1
1.5:1
2a
3a
6.6
30
45
58
64
1
2
.83:1.83
.29:1.83
2.75:1.83
5
5
5
5
5
68
42
1
a
23
8.4
3
3
.21:1.83
.66:1.83
1.75:1
2:1
Minor amount
*
The yields also vary with the concentration of NaOH. With 5 equivalents, the yield of compound 3a was low while with 15 equivalents, an
undesirable insoluble product was obtained. With 10 equivalents, the maximum yield was obtained.

1
106 Mukhtar et al.
Asian J. Chem.
Ar'
O
in anhydrous benzene, refluxing the reaction mixture for 30
h. The products on crystallization from acetone-benzene yielded
an undesired compound, pyridine derivatives 7a (87.0 ꢀ) and
7b (89 ꢀ) instead of the target compound, dithiazolidin-4-
ones (6a and 6b) (Scheme-IV).
Ar
HO
Ar
Ar
Ar'
Ar'
3
3
a: p-Cl-Ph, p-OMe-Ph
b: p-Cl-Ph, p-Cl-Ph
O
Ar
p-TsOH
Ar
Ar'
Ar
Ar
2
2
a: p-Cl-Ph, p-OMe-Ph
b: p-Cl-Ph, p-Cl-Ph
Ar'
O
Ar'
O
O
Ar'
O
Ar
Ar
HS.CH .COOH,
2
(
NH ) CO3
Ar
Ar'
Ar
Ar'
4 2
O
O
Ar
Ar
Yield
a: 93.4%
b: 94.6%
5a, 5b
Ar'
N
Ar
Ar
NH
4
4
HN
S
S
Ar'
Scheme-II: Synthesis of β,γ-unsaturated cyclohexene derivatives
O
O
Ar
Ar
6
a, 6b
Yield
a: 87.0%
b: 89.0%
on that way where there is equatorial hydrogen (cis relation-
ship) required for making up a six-membered transition state
for elimination [25]. A plausible mechanism for this may be
offered as shown in Scheme-III.
7
7
Scheme-IV: Formation of pyridine derivatives
As planned for the synthesis of dithiazolidin-4-ones, the
reaction of 1,5-diketone 2a was carried out with thioglycollic
acid in presence of ammonium carbonate (molar ratio 1:5:10)
Since, the cyclization of 1,5-diketone with ammonia to
form pyridine derivative is a well-known reaction [26,27], it
is understood that ammonium carbonate being in excess
underwent ring closure with 1,5-diketone prior to the attack
with thioglycollic acid. The structures and stereochemistry of
the synthesized compounds have been established by the com-
O
S
O
S
-O
+OH
H
O
Ar"
Ar"
OH
O
H
2
O
H
H
H
1
13
Ar'
H
p-TsOH
Ar' O
H
bined study of FTIR, DCI-mass,APcI-mass, H NMR, C NMR,
Ar O
Ar
O
Ar O
Ar
H
H
1
1
H
H
H- H-COSY, HETCOR and long-range HETCOR spectra. The
Ar
Ar
Ar'
Ar'
assignments of all the signals to individual H or C atoms
(Tables 1-3) have been performed from their typical chemical
shift values, coupling constants and relative integrations.
The coupling constants of compound 3a (Table-1) indicated
that all hydrogen atoms are in axial positions and mutually
H
H
3
a, 3b
p-TsO-
2
-H O
Ar" = p-Me-Ph
O
S
O
Ar"
Ar"
S
anti-periplanar except the diastereotopic CH hydrogen atoms
2
O
O
H
O
O
H
H
H
Ar'
H
at C-6 position. From H and C values of compound 4a (Table-3),
it was evident that the double bond of cyclohexene ring is not
in conjugation with carbonyl group on C-6 (α,β-unsaturated
ketone) as expected, but dehydration went in the other direction
affording β,γ-unsaturated ketone.
Anticancer activities: The results of anticancer activity
of three compounds 3a, 3b and 7a against 3-cell line of three
types of human cancers: breast (MCF7), Lung (NCI-H460)
and CNS (SF-268) in the one dose primary anticancer assay
are given in Table-5. As results showed in Table-5, all these
compounds have not shown any remarkable cytotoxic activity
at 10 µM concentration.
Ar O
O
Ar'
H
Ar O
O
H
H
H
Ar
Ar
Ar
Ar'
Ar
Ar'
H
H
H
Transition state
-
p-TsOH
H
H
O
Ar'
H
O
Ar'
Ar
Ar O
Ar
O
H
Ar
Ar'
Ar
Ar
H
H
H
Ar'
H
H
4
a, 4b
Ar
Ar'
a: p-Cl-Ph, p-OMe-Ph
b: p-Cl-Ph, p-Cl-Ph,
Antimicrobial activities: The results for antimicrobial
activities of the tested compounds detected against the test
organisms Escherichia coli, Bacillus subtilis, Staphylococcus
Scheme-III: A plausible mechanism for the formation of β,γ-unsaturated
cyclohexene derivatives
TABLE-5
RESULT OF ANTICANCER ACTIVITY OF THE COMPOUNDS AGAINST 3-CELL LINES OF HUMAN CANCERS
Retardation of growth (ꢀ)
Test compound
Sample
Concentration
Units
(Breast) MCF7
(Lung) NCI-H460
(CNS) SF-268
3a
3b
7a
1
1
1
1.000E-04
1.000E-04
1.000E-04
Molar
Molar
Molar
72
90
75
86
91
81
77
53
106

Vol. 30, No. 5 (2018)
Test compound
Synthesis, Stereochemistry and Biological Evaluation of Novel Cyclohexanol Derivatives 1107
TABLE-6
ANTIMICROBIAL ACTIVITY OF COMPOUNDS BY AGAR WELL DIFFUSION METHOD
Effective
concentration
Antimicrobial activity in terms of zone of inhibition (mm)
Staphylococcus
aureus
Bacillus
subtilis
Escherichia
coli
Pseudomonas
aeruginosa
Candida
albicans
(µg/well)
3
3
4
4
a
b
a
b
250
250
250
250
–
–
–
–
25
–
–
–
–
–
20
–
19
20
12
20
24
–
13
12
10
15
30
–
–
–
12
–
–
25
Chloramphenicol
Fluconozole
100 µg/well
100 µg/well
aureus, Pseudomonas aeruginosa and Candida albicans are
presented in Table-6. Solvent control (DMSO) showed a non-
significant inhibition to test microorganisms. Antimicrobial
activity against Gram -ve bacteria was deduced in all compounds.
However, such activity was not detected in all compounds against
Gram +ve bacteria.
The compounds exhibited antimicrobial activity at the
concentration of 250 µg/100 µL. One compound 4a also demon-
strated antifungal (anticandidal) activity. Collectively, it has
been found that all compounds (3a, 3b, 4a and 4b) showed
significant antimicrobial activity against Gram -ve bacterial
strains. These compounds may be directly explored in the prepar-
ation of topical anti-infective agents.
REFERENCES
1
.
J. Barluenga, L. Alvarez-Rodrigo, F. Rodriguez, F. Fananas, T. Sordo
and P. Campomanes, Angew. Chem. Int. Ed., 46, 2607 (2007);
https://doi.org/10.1002/anie.200605172.
2. G. Lu and C. Cai, J. Chem. Res., 35, 147 (2011);
https://doi.org/10.3184/174751911X12977065405044.
I. Mamedov, R. Abbasoglu, M. Bayramov and A. Maharramov, Magn.
Reson. Chem., 54, 315 (2016);
3
.
https://doi.org/10.1002/mrc.4377.
4. Y. Obata, C. Jie Li, M. Fujikawa, K. Takayama, H. Sato, K. Higashiyama,
K. Isowa and T. Nagai, Int. J. Pharm., 212, 223 (2001);
https://doi.org/10.1016/S0378-5173(00)00608-6.
S. Pandey, S. Singh, B. Patro and A. Ghosh, Indian J. Chem., 43B, 2705
2004).
6. L. Rong, X. Wei, Y. Lu and Z. Zong, Youji Huaxue, 32, 1999 (2012);
5
.
(
https://doi.org/10.6023/cjoc201204004.
Conclusion
7
8
.
.
G. Rogers, S. Parsons, D. Anderson, L. Nilsson, B. Bahr, W. Kornreich,
R. Kaufman, R. Jacobs and B. Kirtman, J. Med. Chem., 32, 1217 (1989);
https://doi.org/10.1021/jm00126a013.
K. Anan, M. Masui, S. Hara, M. Ohara, M. Kume, S. Yamamoto, S.
Shinohara, H. Tsuji, S. Shimada, S.Yagi, N. Hasebe and H. Kai, Bioorg.
Med. Chem. Lett., 27, 4194 (2017);
https://doi.org/10.1016/j.bmcl.2017.06.076.
A. Dhir, S. Malik, S.V. Kessar, K.N. Singh and S.K. Kulkarni, Eur.
Neuropsychopharmacol., 21, 705 (2011);
The aim of this work was to synthesize dithiazolidin-4-
one derivatives from chalcones via the formation of 1,5-diketones.
During the synthesiz of 1,5-diketones (2a and 2b) from chalcones
(
1a and 1b) by the Michael addition of p-chloroacetophenone
in the presence of NaOH (molar ratio, 1:1:10), a novel cyclo-
hexanol derivative was obtained as a side product. Keeping in
view of the novelty of the side product, the same reaction was
repeated with different molar ratios of chalcone-acetophenone-
sodium hydroxide to set the optimum condition to obtain maxi-
mum yield of cyclohexanol and thus the ratio was fixed as
9
.
https://doi.org/10.1016/j.euroneuro.2010.12.003.
10. D.C. Kosegarten, J.J. Defeo and D.R. DeFanti, J. Pharm. Sci., 56, 1104
1967);
https://doi.org/10.1002/jps.2600560911.
1. V. Mahyavanshi, S.I. Marjadi and R. Yadav, Arab. J. Chem., 10, S804
(
1
1
2
:1:10. The dehydration of cyclohexanols 3a and 3b with
(
2017);
catalytic amount of p-TsOH resulted in an unusual stereo-
selective syn-elimination producing quantitative yields of β,γ-
unsaturated cyclohexenes 4a (94.4ꢀ) and 4b (93.4ꢀ) instead
of apparently more stable α,β-unsaturated cyclohexenes. Com-
pounds 3a, 3b and 7a have not shown any significant anti-
cancer activity against three types of human cancers in the
one dose primary anticancer assay. The results of antimicrobial
studies showed that all compounds demonstrated significant
antimicrobial activity against Gram -ve bacterial strains at the
concentration of 250 µg/100 µL.
https://doi.org/10.1016/j.arabjc.2012.12.009.
2. H. Parveen, F. Hayat, S. Mukhtar, A. Salahuddin, A. Khan, F. Islam and
A. Azam, Eur. J. Med. Chem., 46, 4669 (2011);
https://doi.org/10.1016/j.ejmech.2011.05.055.
3. H. Parveen, S. Mukhtar andA.Azam, J. Heterocycl. Chem., 53, 473 (2016);
https://doi.org/10.1002/jhet.2427.
4. H. Parveen, R.A.S. Alatawi, N.H. El Sayed, S. Hasan, S. Mukhtar and
A.U. Khan, Arab. J. Chem., 10, 1098 (2017);
https://doi.org/10.1016/j.arabjc.2015.05.002.
5. S. Mukhtar, M.I. Al-Ahmdi and H. Parveen, Asian J. Chem., 28, 2589
(2016);
1
1
1
1
1
1
1
2
https://doi.org/10.14233/ajchem.2016.19908.
6. K. Salat, A. Moniczewski and T. Librowski, Mini Rev. Med. Chem.,
1
3, 335 (2013);
ACKNOWLEDGEMENTS
https://doi.org/10.2174/1389557511313030003.
7. T. Torroba, J. Prakt. Chem., 341, 99 (1999);
https://doi.org/10.1002/(SICI)1521-3897(199902)341:2<99::AID-
PRAC99>3.0.CO;2-Z.
8. V.P.M. Rahman, S. Mukhtar, W.H. Ansari and G. Lemiere, Eur. J. Med.
Chem., 40, 173 (2005);
https://doi.org/10.1016/j.ejmech.2004.10.003.
9. S. Mukhtar, M. Rahman, W. Ansari, G. Lemière, A. De Groot and R.
Dommisse, Molecules, 4, 232 (1999);
The authors acknowledge the financial support for this work
from the Deanship of Scientific Research (DSR), University
of Tabuk, Tabuk, SaudiArabia under Grant No. (S-0116-1437).
The authors are also thankful to National Cancer Institute (NCI),
Bethesda, Maryland, USA for in vitro anticancer screening and
Prof. Iqbal Ahmad, Department of Agricultural Microbiology,
Aligarh Muslim University, Aligarh, India for performing
antimicrobial studies of synthesized compound.
https://doi.org/10.3390/40700232.
0. G.D. Gray and E. Wickstrom, Biotechniques, 21, 780 (1996).

1
108 Mukhtar et al.
Asian J. Chem.
2
2
1. C. Perez, M. Pauli and P. Bazerque, Acta Biol. Exp., 15, 113 (1990).
2. A.Z. Beg and I. Ahmad, World J. Microbiol. Biotechnol., 16, 841 (2000);
https://doi.org/10.1023/A:1008991724288.
3. A. Lubineau and J. Auge, Tetrahedron Lett., 33, 8073 (1992);
https://doi.org/10.1016/S0040-4039(00)74720-4.
25. J. March, Advanced Organic Chemistry, John Wiley & Sons, edn 4, p.
1009 (1992).
26. M. Weiss, J. Am. Chem. Soc., 74, 200 (1952);
https://doi.org/10.1021/ja01121a051.
2
2
27. F. Krohnke, Synthesis, 1 (1976);
4. R.Antonioletti, F. Bonadies, E.S. Monteagudo andA. Scettri, Tetrahedron
Lett., 32, 5373 (1991);
https://doi.org/10.1055/s-1976-23941.
https://doi.org/10.1016/S0040-4039(00)92389-X.