Synthesis of novel 1,8-dioxo octahydroacridine functionalized thioureas and thiazolidinones and evaluation of their antimicrobial activities

Article abstract of DOI:10.1007/s13738-016-1024-6

New series of thiourea and thiazolidinone derivatives containing a 1,8-dioxo octahydroacridinyl moiety have been synthesized through the reaction of 1-(4-Amino-phenyl)-3-methyl-thiourea with various aromatic aldehydes and dimedone. All the synthesized compounds were tested against several microbial pathogens Staphylococcus aureus, Micrococcus luteus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Candida albicans.

Full text of DOI:10.1007/s13738-016-1024-6

J IRAN CHEM SOC
DOI 10.1007/s13738-016-1024-6
ORIGINAL PAPER
Synthesis of novel 1,8‑dioxo octahydroacridine functionalized
thioureas and thiazolidinones and evaluation of their
antimicrobial activities
Arman Shokooh Saljooghi1 · Hojatollah Khabazzadeh1 · Moj Khaleghi2
Received: 9 August 2016 / Accepted: 5 December 2016
© Iranian Chemical Society 2016
Abstract New series of thiourea and thiazolidinone deriv-
atives containing a 1,8-dioxo octahydroacridinyl moiety
have been synthesized through the reaction of 1-(4-Amino-
phenyl)-3-methyl-thiourea with various aromatic aldehydes
and dimedone. All the synthesized compounds were tested
against several microbial pathogens Staphylococcus aureus,
Micrococcus luteus, Escherichia coli, Pseudomonas aerug-
inosa, Klebsiella pneumoniae and Candida albicans.
Various 1, 3-disubstituted thiourea derivatives are excep-
tionally flexible building blocks for the synthesis of a col-
lection of heterocyclic compounds and exhibit a wide range
of biological activities. Many thiourea derivatives exhibited
remarkable antimicrobial activities [8]; 1, 3-dialkyl or dia-
ryl thiourea derivatives showed significant antifungal activ-
ity against plant pathogens [9].
Keywords Thiourea · Thiazolidinone · 1,8-Dioxo
octahydroacridine · Dialkyl acetylenedicarboxylate ·
Antimicrobial
Experimental
All chemicals purchased from Merck chemical company
and used without further purification.
1H NMR and 13C NMR spectra were recorded on a
Bruker Ultrashield-400 NMR spectrometer using DMSO-
d6 as a solvent. IR spectra were recorded on a Bruker
Tensor-27 FT-IR spectrophotometer using KBr pellets.
Melting points were measured on an Electrothermal-9100
apparatus. Elemental analyses were run on a LECO-932
series.
Introduction
One of the important heterocyclic systems that exists in
biologically active compounds is thiazole ring. Thiazoles
are present in many biologically active molecules such as
antimicrobial drugs (sulfathiazole and penicillin) [1].
Acridine derivatives are another important heterocyclic
structures having antimalarial, antiviral and antiallergic
properties [2–4]; acridines act as powerful drugs for anti-
tumor activity both in vitro and in vivo against some of rat
and human tumors [5]. Some of fluorinated acridones were
announced to have anticancer activity [6, 7].
Synthesis of 1‑(4‑Amino‑phenyl)‑3‑methyl‑thiourea 1
A mixture of 1, 4-phenylene diamine (10 mmol) and
methyl isothiocyanate (10 mmol) in 20 mL ethanol was
heated at 60 °C. The promotion of the reaction was moni-
tored by TLC. When the reaction was completed (90 min),
the solvent was vaporized and remaining solid was
washed with the mixture of hexane/ethyl acetate (9:1).
The resultant precipitate was filtered and dried. After that,
the precipitate was dissolved in 20% HCl solution and
filtered. Then, 10% NaOH solution was added to the fil-
tered solution until pH 7–8 was obtained and 1-(4-Amino-
phenyl)-3-methyl-thiourea 1 as a white precipitate was
separated.
* Hojatollah Khabazzadeh
hkhabazzadeh@uk.ac.ir
1
Department of Chemistry, Shahid Bahonar University
of Kerman, Kerman 7616914111, Iran
2
Department of Biology, Shahid Bahonar University
of Kerman, Kerman 7616914111, Iran
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J IRAN CHEM SOC
1‑(4‑Amino‑phenyl)‑3‑methyl‑thiourea (1)
C, 67.93; H, 6.25; N, 7.67%. Found. C, 68.09; H, 6.15; N,
7.90%.
White solid, mp 173–176 °C. IR (KBr): 1565, 1630, 2935,
3000, 3165, 3370 cm−1. 1H NMR (DMSO-d6 400 MHz), δ
(ppm): 2.87 (3H, d, J = 4.0 Hz, CH3), 5.06 (2H, s, NH2),
6.54 (2H, d, J = 8.4 Hz, arom), 6.86 (2H, d, J = 8.4 Hz,
arom), 7.12 (1H, s, NH, thiourea), 9.07 (1H, s, NH, thiou-
rea). 13C NMR (DMSO-d6 100 MHz), δ (ppm): 31.3, 114.0,
126.5, 146.7, 181.1. Anal. Calcd. For C8H11N3S: C, 53.01;
H, 6.12; N, 23.18%. Found. C, 53.18; H, 6.31; N, 22.97%.
1‑(4‑(9‑(4‑methoxyphenyl)‑3, 3, 6,
6‑tetramethyl‑1,8‑dioxo‑2, 3, 4, 5, 6, 7, 8,
9‑octahydroacridin‑10(1H)‑yl)phenyl)‑3‑methylthiourea
(3c)
Pale goldenrod solid; mp 170–173 °C; IR (KBr): 1637,
2869, 2955, 3060, 3326 cm−1 1H NMR (DMSO-d6
.
400 MHz), δ (ppm): 0.73 (6H, s, 2CH3), 0.89 (6H, s,
2CH3), 1.79–2.24 (8H, m, 4CH2), 2.94 (3H, d, J = 3.6 Hz,
N–CH3), 3.69 (3H, s, O-CH3), 4.97 (1H, s, CH), 6.80 (2H,
d, J = 8.8 Hz, arom), 7.21 (2H, d, J = 8.8 Hz, arom), 7.27–
7.35 (2H, m, arom), 7.73 (2H, d, J = 8.4 Hz, arom), 7.97
(1H, s, br, NH), 9.88 (1H, s, br, NH). 13C NMR (DMSO-
d6 100 MHz), δ (ppm): 26.1, 29.3, 30.8, 31.1, 31.9, 40.8,
49.5, 54.8, 113.1, 113.2, 122.4, 128.3, 128.9, 133.1, 138.5,
140.2, 150.3, 157.2, 180.8 (C=S), 195.0 (C=O). Anal.
Calcd. For C32H37N3O3S: C, 70.69; H, 6.86; N, 7.73%.
Found. C, 70.88; H, 6.97; N, 7.95%.
General procedure for the synthesis of 3a–e
A mixture of an aldehyde (1 mmol), dimedone (2 mmol),
1-(4-Amino-phenyl)-3-methyl-thiourea (1.5 mmol) and one
drops of HCl in 5 mL DMF was refluxed for the appropri-
ate time. When the reaction was completed (indicated by
TLC), the mixture was discharged into cold water. The
resulting precipitate was purified by column chromatogra-
phy ethyl acetate/hexane (9:1) to afford decahydroacridine-
1,8-diones 3a–e.
1‑Methyl‑3‑(4‑(3, 3, 6, 6‑tetramethyl‑1,8‑dioxo‑9‑
phenyl‑2, 3, 4, 5, 6, 7, 8, 9‑octahydroacridin‑10(1H)‑yl)
phenyl)thiourea (3a)
1‑methyl‑3‑(4‑(3, 3, 6, 6‑tetramethyl‑9‑
(4‑nitrophenyl)‑1,8‑dioxo‑2, 3, 4, 5, 6, 7, 8,
9‑octahydroacridin‑10(1H)‑yl)phenyl)thiourea (3d)
Pale goldenrod solid; mp 168-170 °C; IR (KBr): 1637,
Saddle brown solid; mp 175–178 °C; IR (KBr): 1642,
1
1
2869, 2956, 3027, 3058, 3323 cm−1. H NMR (DMSO-
2868, 2957, 3058, 3345, 3389 cm−1. H NMR (DMSO-
d6 400 MHz), δ (ppm): 0.72 (6H, s, 2CH3), 0.89 (6H, s,
2CH3), 1.82–2.26 (8H, m, 4CH2), 2.98 (3H, d, J = 4.0 Hz,
N–CH3), 5.07 (1H, s, CH), 7.09 (1H, t, J = 7.2 Hz, arom),
7.24 (2H, t, J = 7.6 Hz, arom), 7.33 (2H, d, J = 7.2 Hz,
arom), 7.78 (2H, d, J = 8.4 Hz, arom) 8.01 (1H, s, br, NH),
9.91 (1H, s, br, NH). 13C NMR (DMSO-d6 100 MHz), δ
(ppm): 26.1, 29.3, 31.0, 31.8, 31.9, 40.9, 49.5, 112.9, 122.3,
125.7, 127.4, 127.8, 129.0, 133.1, 140.4, 146.2, 150.6,
180.9, 195.0. Anal. Calcd. For C31H35N3O2S: C, 72.34; H,
6.87; N, 8.18%. Found. C, 72.18; H, 6.64; N, 8.40%.
d6 400 MHz), δ (ppm): 0.71 (6H, s, 2CH3), 0.90 (6H, s,
2CH3), 1.83–2.27 (8H, m, 4CH2), 2.98 (3H, d, J = 4.0 Hz,
N–CH3), 5.13 (1H, s, CH), 7.39 (2H, d, J = 8.0 Hz, arom),
7.58 (2H, d, J = 8.8 Hz, arom), 7.77 (2H, d, J = 8.0 Hz,
arom), 8.02 (1H, s, br, NH), 8.15 (2H, d, J = 8.4 Hz, arom),
9.94 (1H, s, br, NH). 13C NMR (DMSO-d6 100 MHz), δ
(ppm): 26.1, 29.1, 31.0, 31.9, 32.7, 40.8, 49.3, 111.8, 121.9,
123.3, 128.8, 129.2, 140.4, 140.5, 145.6, 151.3, 153.6,
180.9, 195.0. Anal. Calcd. For C31H34N4O4S: C, 66.64; H,
6.13; N, 10.03%. Found. C, 66.82; H, 6.25; N, 10.27%.
1‑(4‑(9‑(4‑chlorophenyl)‑3, 3, 6, 6‑tetramethyl‑1,8‑
dioxo‑2, 3, 4, 5, 6, 7, 8, 9‑octahydroacridin‑10(1H)‑yl)
phenyl)‑3‑methylthiourea (3b)
1‑(4‑(9‑(3, 4‑dihydroxyphenyl)‑3, 3, 6,
6‑tetramethyl‑1,8‑dioxo‑2, 3, 4, 5, 6, 7, 8,
9‑octahydroacridin‑10(1H)‑yl)phenyl)‑3‑methylthiourea
(3e)
Pale goldenrod solid; mp 156–158 °C; IR (KBr): 1637,
2869, 2957, 3044, 3325 cm−1
.
1H NMR (DMSO-d6
Pale goldenrod solid; mp 255–258 °C; IR (KBr): 1631,
2871, 2966, 3314 cm-1. 1H NMR (DMSO-d6 400 MHz), δ
(ppm): 0.75 (6H, s, 2CH3), 0.89 (6H, s, 2CH3), 1.78–2.22
(8H, m, 4CH2), 2.98 (3H, d, J = 4.0 Hz, N–CH3), 4.88 (1H,
s, CH), 6.53–6.58 (2H, m, arom), 6.74 (1H, d, J = 1.6 Hz,
arom), 7.30–7.36 (2H, m, arom), 7.74 (2H, d, J = 8.8 Hz,
arom), 7.95 (1H, s, br, NH), 8.46 (1H, s, br, OH), 7.70
(1H, s, br, OH), 9.83 (1H, s, br, NH). 13C NMR (DMSO-
d6 100 MHz), δ (ppm): 26.2, 27.9, 28.6, 29.3, 30.6, 31.9,
400 MHz), δ (ppm): 0.72 (6H, s, 2CH3), 0.89 (6H, s,
2CH3), 1.83–2.26 (8H, m, 4CH2), 2.98 (3H, d, J = 4.0 Hz,
N–CH3), 5.05 (1H, s, CH), 7.28–7.35 (6H, m, arom), 7.79
(2H, d, J = 7.0 Hz, arom), 8.02 (1H, s, br, NH), 9.92 (1H,
s, br, NH). 13C NMR (DMSO-d6 100 MHz), δ (ppm): 26.1,
29.2, 31.0, 31.6, 31.9, 40.8, 49.5, 112.5, 127.7, 127.8,
129.3, 129.8, 130.2, 132.9, 140.4, 145.1, 150.8, 180.9
(C=S), 195.0 (C=O). Anal. Calcd. For C31H34ClN3O2S:
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J IRAN CHEM SOC
40.8, 49.6, 113.3, 115.0, 115.1, 118.0, 135.3, 137.6, 140.2,
143.1, 144.4, 150.0, 160.2, 162.3, 180.8, 195.0. Anal.
Calcd. For C31H35N3O4S: C, 68.23; H, 6.46; N, 7.70%.
Found. C, 68.08; H, 6.58; N, 7.93%.
Methyl (Z)‑2‑((E)‑2‑((4‑(9‑(4‑chlorophenyl)‑3,
3, 6, 6‑tetramethyl‑1,8‑dioxo‑2, 3, 4, 5, 6,
7, 8, 9‑octahydroacridin‑10(1H)‑yl)phenyl)
imino)‑3‑methyl‑4‑oxothiazolidin‑5‑ylidene)acetate (4c)
General procedure for the synthesis of 4a–j
Pale yellow solid; mp 154–156 °C; IR (KBr): 1637, 1728,
2870, 2955, 3063 cm−1. 1H NMR (DMSO-d6 400 MHz), δ
(ppm): 0.75 (6H, s, 2CH3), 0.92 (6H, s, 2CH3), 1.83–2.30
(8H, m, 4CH2), 3.35 (3H, s, N–CH3), 3.74 (3H, s, O-CH3),
5.05 (1H. s, CH), 6.85 (1H-vinyl, s, CH), 7.23 (2H, d,
J = 8.8 Hz, arom), 7.30 (2H, d, J = 8.4 Hz, arom), 7.35
(2H, d, J = 8.4 Hz, arom), 7.48 (2H, m, arom). 13C NMR
(DMSO-d6 100 MHz), δ (ppm): 26.1, 29.2, 29.3, 31.7, 31.9,
40.9, 49.4, 52.5, 112.6, 115.5, 122.5, 127.8, 129.4, 129.8,
130.2, 135.0, 140.9, 145.1, 147.8, 150.6, 152.4, 164.3,
165.6, 194.9. Anal. Calcd. For C36H36ClN3O5S: C, 65.69;
H, 5.51; N, 6.38%. Found. C, 65.86; H, 5.70; N, 6.15%.
To a magnetically stirred solution of 3 (1 mmol) in ethanol
(10 mL) was added DAAD (1 mmol) at ambient tempera-
ture. The reaction mixture was then stirred for the appro-
priate time. The solvent was removed under reduced pres-
sure and the residue recrystallized from 2:1 hexane–ethyl
acetate affording products 4a–j.
Methyl (Z)‑2‑((E)‑3‑methyl‑4‑oxo‑2‑((4‑(3, 3, 6,
6‑tetramethyl‑1,8‑dioxo‑9‑phenyl‑2, 3, 4, 5, 6, 7,
8, 9‑octahydroacridin‑10(1H)‑yl)phenyl)imino)
thiazolidin‑5‑ylidene)acetate (4a)
Ethyl (Z)‑2‑((E)‑2‑((4‑(9‑(4‑chlorophenyl)‑3,
3, 6, 6‑tetramethyl‑1,8‑dioxo‑2, 3, 4, 5, 6,
7, 8, 9‑octahydroacridin‑10(1H)‑yl)phenyl)
imino)‑3‑methyl‑4‑oxothiazolidin‑5‑ylidene)acetate (4d)
Pale yellow solid; mp 152–154 °C; IR (KBr): 1637,
1
1728, 2869, 2954, 3028, 3059 cm−1. H NMR (DMSO-d6
400 MHz), δ (ppm): 0.83 (6H, s, 2CH3), 1.00 (6H, s, 2CH3),
1.90–2.38 (8H, m, 4CH2), 3.43 (3H, s, N–CH3), 3.82 (3H,
s, O-CH3), 5.14 (1H, s, CH), 6.93 (1H-vinyl, s, CH), 7.18
(1H, t, J = 7.6 Hz, arom), 7.30–7.35 (4H, m, arom), 7.41
(2H, d, J = 6.8 Hz, arom), 7.53–7.54 (2H, m, arom). 13C
NMR (DMSO-d6 100 MHz), δ (ppm): 26.0, 29.2, 29.3,
31.9, 32.0, 40.9, 49.5, 52.5, 113.0, 115.5, 122.6, 125.7,
127.5, 127.8, 135.1, 140.9, 145.7, 146.2, 147.8, 150.4,
152.5, 164.3, 165.6, 195.0. Anal. Calcd. For C36H37N3O5S:
C, 69.32; H, 5.98; N, 6.74%. Found. C, 69.36; H, 6.17; N,
6.49%.
Pale yellow solid; mp 151–153 °C; IR (KBr): 1637, 1697,
1726, 2870, 2958 cm−1. 1H NMR (DMSO-d6 400 MHz), δ
(ppm): 0.82 (6H, s, 2CH3), 0.99 (6H, s, 2CH3), 1.30 (3H,
t, J = 7.2 Hz, CH3), 1.89–2.37 (8H, m, 4CH2), 3.40 (3H,
s, N–CH3), 4.27 (2H, q, J = 7.2 Hz, O-CH2), 5.11 (1H,
s, CH), 6.89 (1H-vinyl, s, CH), 7.30 (2H, d, J = 8.4 Hz,
arom), 7.37–7.43 (4H, m, arom), 7.55 (2H, m, arom).
13C NMR (DMSO-d6 100 MHz), δ (ppm): 13.9, 26.1,
29.2, 29.3, 31.7, 31.9, 40.9, 49.4, 61.4, 112.6, 115.8,
122.4, 122.5, 127.8, 129.4, 130.2, 135.0, 140.7, 145.1,
147.8, 150.6, 152.5, 164.3, 165.1, 195.0. Anal. Calcd. For
C37H38ClN3O5S: C, 66.11; H, 5.70; N, 6.25%. Found. C,
66.27; H, 5.82; N, 6.46%.
Ethyl (Z)‑2‑((E)‑3‑methyl‑4‑oxo‑2‑((4‑(3, 3, 6,
6‑tetramethyl‑1,8‑dioxo‑9‑phenyl‑2, 3, 4, 5, 6, 7,
8, 9‑octahydroacridin‑10(1H)‑yl)phenyl)imino)
thiazolidin‑5‑ylidene)acetate (4b)
Methyl (Z)‑2‑((E)‑2‑((4‑(9‑(4‑methoxyphenyl)‑3,
3, 6, 6‑tetramethyl‑1,8‑dioxo‑2, 3, 4, 5, 6,
7, 8, 9‑octahydroacridin‑10(1H)‑yl)phenyl)
imino)‑3‑methyl‑4‑oxothiazolidin‑5‑ylidene)acetate (4e)
Pale yellow solid; mp 121–123 °C; IR (KBr): 1637,
1
1698, 1726, 2870, 2957, 3059 cm−1. H NMR (DMSO-d6
400 MHz), δ (ppm): 0.72 (6H, s, 2CH3), 0.89 (6H, s, 2CH3),
1.19 (3H, t, J = 7.2 Hz, CH3), 1.80–2.27 (8H, m, 4CH2),
3.31 (3H, s, N–CH3), 4.17 (2H, q, J = 7.2 Hz, O-CH2),
5.05 (1H, s, CH), 6.78 (1H-vinyl, s, CH), 7.07 (1H, t,
J = 7.2 Hz, arom), 7.19–7.24 (4H, m, arom), 7.31 (2H,
d, J = 8.0 Hz arom), 7.42–7.43 (2H, m, arom). 13C NMR
(DMSO-d6 100 MHz), δ (ppm): 13.8, 26.0, 28.6, 29.2,
31.8, 31.9, 40.9, 49.5, 61.4, 113.0, 115.8, 125.7, 127.5,
127.7, 127.8, 128.0, 135.1, 140.7, 146.2, 147.8, 150.3,
152.5, 164.3, 165.1, 194.9. Anal. Calcd. For C37H39N3O5S:
C, 69.68; H, 6.16; N, 6.59%. Found. C, 69.79; H, 6.29; N,
6.81%.
Pale yellow solid; mp 139–142 °C; IR (KBr): 1637, 1728,
1
2834, 2954, 3060 cm−1. H NMR (DMSO-d6 400 MHz),
δ (ppm): 0.90 (6H, s, 2CH3), 1.06 (6H, s, 2CH3), 1.94–
2.43 (8H, m, 4CH2), 3.49 (3H, s, N–CH3), 3.84 (3H, s,
O-CH3), 3.88 (3H, s, O-CH3), 5.13 (1H, s, CH), 6.96 (2H,
d, J = 8.4 Hz, arom), 6.99 (1H-vinyl, s, CH), 7.37 (4H, m,
J = 8.4 Hz, arom), 7.59 (2H, m, arom). 13C NMR (DMSO-
d6 100 MHz), δ (ppm): 26.1, 28.6, 29.3, 30.9, 31.9, 40.9,
49.5, 52.5, 54.8, 113.2, 113.3, 115.4, 122.5, 128.4, 128.9,
135.2, 138.5, 140.9, 147.7, 150.1, 152.5, 157.2, 164.3,
1 3

J IRAN CHEM SOC
165.7, 195.0. Anal. Calcd. For C37H39N3O6S: C, 67.97; H,
6.01; N, 6.43%. Found. C, 67.79; H, 5.90; N, 6.62%.
J = 8.8 Hz, arom), 8.15 (2H, d, J = 8.8 Hz, arom). 13C
NMR (DMSO-d6 100 MHz), δ (ppm): 13.9, 26.1, 29.1,
29.2, 31.9, 32.8, 40.9, 49.3, 61.5, 111.9, 113.8, 115.7,
122.3, 123.2, 127.9, 128.9, 134.9, 140.7, 145.6, 147.9,
151.1, 152.6, 153.6, 164.3, 165.1, 195.3. Anal. Calcd. For
C37H38N4O7S: C, 65.09; H, 5.61; N, 8.21%. Found. C,
65.26; H, 5.73; N, 8.42%.
Ethyl (Z)‑2‑((E)‑2‑((4‑(9‑(4‑methoxyphenyl)‑3,
3, 6, 6‑tetramethyl‑1,8‑dioxo‑2, 3, 4, 5, 6,
7, 8, 9‑octahydroacridin‑10(1H)‑yl)phenyl)
imino)‑3‑methyl‑4‑oxothiazolidin‑5‑ylidene)acetate (4f)
Pale yellow solid; mp 122–125 °C; IR (KBr): 1636, 1726,
2834, 2957, 3060 cm−1. 1H NMR (DMSO-d6 400 MHz), δ
(ppm): 0.75 (6H, s, 2CH3), 0.91 (6H, s, 2CH3), 1.22 (3H,
t, J = 7.2 Hz, CH3), 1.80–2.28 (8H, m, 4CH2), 3.34 (3H,
s, N–CH3), 3.69 (3H, s, O-CH3), 4.19 (2H, q, J = 7.2 Hz,
O-CH2), 4.98 (1H, s, CH), 6.81 (2H, d, J = 8.8 Hz, arom),
6.82 (1H-vinyl, s, CH), 7.23 (4H, d, J = 8.8 Hz, arom),
7.43–7.45 (2H, m, arom). 13C NMR (DMSO-d6 100 MHz),
δ (ppm): 13.9, 26.1, 28.6, 29.3, 30.9, 31.9, 40.9, 49.5,
54.8, 61.5, 113.2, 113.3, 115.7, 122.3, 128.4, 128.9, 135.2,
138.5, 140.8, 147.8, 150.1, 152.5, 157.2, 164.3, 165.1,
195.0. Anal. Calcd. For C38H41N3O6S: C, 68.34; H, 6.19;
N, 6.29%. Found. C, 68.49; H, 6.26; N, 6.08%.
Methyl (Z)‑2‑((E)‑2‑((4‑(9‑(3, 4‑dihydroxyphenyl)‑3,
3, 6, 6‑tetramethyl‑1,8‑dioxo‑2, 3, 4, 5, 6,
7, 8, 9‑octahydroacridin‑10(1H)‑yl)phenyl)
imino)‑3‑methyl‑4‑oxothiazolidin‑5‑ylidene)acetate (4i)
Pale yellow solid; mp 244–247 °C; IR (KBr): 1634,
1
1727, 2870, 2955, 3063, 3446 cm−1. H NMR (DMSO-
d6 400 MHz), δ (ppm): 0.78 (6H, s, 2CH3), 0.92 (6H, s,
2CH3), 1.79–2.28 (8H, m, 4CH2), 3.39 (3H, s, N–CH3),
3.74 (3H, s, O-CH3), 4.91 (1H, s, CH), 6.59 (2H, s, arom),
6.78 (1H, s, arom), 6.84 (1H-vinyl, s, CH), 7.24 (2H, d,
J = 5.6 Hz, arom), 7.45 (2H, s, arom), 8.48 (1H, s, br, OH),
8.73 (1H, s, br, OH). 13C NMR (DMSO-d6 100 MHz), δ
(ppm): 26.1, 29.2, 29.3, 30.7, 31.9, 40.9, 49.6, 52.5, 113.5,
115.0, 115.1, 115.5, 118.1, 121.8, 123.8, 135.3, 137.6,
140.8, 143.1, 144.4, 147.7, 149.8, 152.4, 164.3, 165.6,
195.0. Anal. Calcd. For C36H37N3O7S: C, 65.94; H, 5.69;
N, 6.41%. Found. C, 65.76; H, 5.82; N, 6.22%.
Methyl (Z)‑2‑((E)‑3‑methyl‑4‑oxo‑2‑((4‑(3, 3, 6,
6‑tetramethyl‑9‑(4‑nitrophenyl)‑1,8‑dioxo‑2, 3, 4, 5,
6, 7, 8, 9‑octahydroacridin‑10(1H)‑yl)phenyl)imino)
thiazolidin‑5‑ylidene)acetate (4g)
Brown solid; mp 174–177 °C; IR (KBr): 1637, 1727, 2870,
2955, 3036, 3062 cm−1. 1H NMR (DMSO-d6 400 MHz), δ
(ppm): 0.74 (6H, s, 2CH3), 0.92 (6H, s, 2CH3), 1.84–2.31
(8H, m, 4CH2), 3.35 (3H, s, N–CH3), 3.74 (3H, s, O-CH3),
5.14 (1H. s, CH), 6.85 (1H-vinyl, s, CH), 7.24 (2H, d,
J = 7.6 Hz, arom), 7.55 (2H, d, J = 8.4 Hz, arom), 7.61
(2H, d, J = 8.8 Hz, arom), 8.16 (2H, d, J = 8.8 Hz, arom).
13C NMR (DMSO-d6 100 MHz), δ (ppm): 26.1, 29.1, 29.3,
31.9, 32.8, 40.9, 49.3, 52.5, 111.9, 115.4, 122.2, 123.3,
128.9, 134.9, 140.9, 142.4, 145.6, 147.9, 151.1, 152.5,
153.6, 164.3, 165.7, 195.0. Anal. Calcd. For C36H36N4O7S:
C, 64.66; H, 5.43; N, 8.38%. Found. C, 64.79; H, 5.52; N,
8.60%.
Ethyl (Z)‑2‑((E)‑2‑((4‑(9‑(3, 4‑dihydroxyphenyl)‑3,
3, 6, 6‑tetramethyl‑1,8‑dioxo‑2, 3, 4, 5, 6,
7, 8, 9‑octahydroacridin‑10(1H)‑yl)phenyl)
imino)‑3‑methyl‑4‑oxothiazolidin‑5‑ylidene)acetate (4j)
Pale yellow solid; mp 235–238 °C; IR (KBr): 1634, 1726,
1
2870, 2957, 3438 cm−1. H NMR (DMSO-d6 400 MHz),
δ (ppm): 0.77 (6H, s, 2CH3), 0.91 (6H, s, 2CH3), 1.21
(3H, t, J = 7.2 Hz, CH3), 1.78–2.27 (8H, m, 4CH2), 3.34
(3H, s, N–CH3), 4.19 (2H, q, J = 7.2 Hz, O-CH2), 4.90
(1H, s, CH), 6.58 (2H, s, arom), 6.77 (2H, s, arom), 6.80
(1H-vinyl, s, CH), 7.23 (2H, d, J = 7.2 Hz, arom), 7.44
(2H, s, arom), 8.50 (1H, s, br, OH), 8.75 (1H, s, br, OH).
13C NMR (DMSO-d6 100 MHz), δ (ppm): 13.8, 26.1, 27.9,
29.3, 30.7, 31.9, 40.9, 49.6, 61.5, 113.4, 115.0, 115.1,
115.7, 118.1, 121.8, 123.9, 135.3, 137.5, 140.7, 143.1,
144.4, 147.7, 149.8, 152.5, 164.3, 165.1, 195.0. Anal.
Calcd. For C36H37N3O7S: C, 66.35; H, 5.87; N, 6.27%.
Found. C, 66.16; H, 5.99; N, 6.45%.
Ethyl (Z)‑2‑((E)‑3‑methyl‑4‑oxo‑2‑((4‑(3, 3, 6,
6‑tetramethyl‑9‑(4‑nitrophenyl)‑1,8‑dioxo‑2, 3, 4, 5,
6, 7, 8, 9‑octahydroacridin‑10(1H)‑yl)phenyl)imino)
thiazolidin‑5‑ylidene)acetate (4h)
Brown solid; mp 169–171 °C; IR (KBr): 1639, 1697,
1724, 2958, 3074 cm−1. 1H NMR (DMSO-d6 400 MHz), δ
(ppm): 0.74 (6H, s, 2CH3), 0.92 (6H, s, 2CH3), 1.22 (3H,
t, J = 7.2 Hz, CH3), 1.84–2.31 (8H, m, 4CH2), 3.35 (3H,
s, N–CH3), 4.19 (2H, q, J = 7.2 Hz, O-CH2), 5.14 (1H,
s, CH), 6.81 (1H-vinyl, s, CH), 7.24 (2H, d, J = 7.6 Hz,
arom), 7.54 (2H, d, J = 7.6 Hz, arom) 7.61 (2H, d,
Determination of antimicrobial activity
Initial antibacterial screening was carried out by the disk
diffusion method using paper disks. The sterilized (auto-
claved at 120 °C for 30 min), liquified Mueller–Hinton agar
(40–50 °C) was inoculated (1 mL/100 mL of medium) with
1 3

J IRAN CHEM SOC
the suspension of the microorganism (turbidity was stand-
ardized to 0.5 McFarland) and discharged into a Petri dish
to give a depth of 3–4 mm. The paper disks impregnated
with the test compounds (100 mg/mL in dimethylsulfox-
ide) were placed on the solidified medium. The plates were
incubated at 37 °C for 24 h.
Minimum inhibitory concentration (MIC)
MIC was ascertained for the compounds showing antimi-
crobial activity. Broth microdilution method was used for
the determination of MIC values. The compounds were
dissolved in DMSO to make 100 mg/mL final concentra-
tion. Then the compounds added to broth media in 96 wells
of microtiter plates using two-fold serial dilution (from
100 mg/mL to 49 µg/mL). Thereafter, 100 µL inoculum
of standard size was added to each well. Bacterial suspen-
sions were used as positive control. The microtiter plates
were incubated at 37 °C for 24 h. In wells where there
was no visible growth, 10 µL of suspension was subcul-
tured to media agar plates, and the agar plates were incu-
bated at 37 °C for colony count. MBC was defined as the
lowest dilution showing P value 99.9% kill after 24 h of
incubation.
Scheme 1 Synthesis of 1-(4-Amino-phenyl)-3-methyl-thiourea
crystal violet. The microtiter plate was incubated at room
temperature for 10–15 min. After that, the plate was washed
3–4 times with water and dried. Absorbance at 540 nm was
read after dissolution of the dye with 95% ethanol and in an
enzyme-linked immunosorbent assay (ELISA) plate reader.
Values of biofilm formation of all strains were compared
with the data for the negative control.
Results and discussion
As a part of our research program to synthesis of novel
1,8-acridindinones and thiazolidinones [11, 12], we have
used 1-(4-Amino-phenyl)-3-methyl-thiourea 1 to synthe-
size various 1,8- acridinyl thiourea derivatives 3 with the
goal to have antimicrobial activities. The synthesized acri-
dinones were then reacted with dialkyl acetylenedicarboxy-
lates (DAAD) to form thiazolidine-4-ones 4.
In the first stage, amino thiourea 1 was synthesized from
the reaction of p-phenylene diamine and methyl isothiocy-
anate in ethanol as solvent. The 1:1 ratio of reactants was
used to reduce the formation of 1, 1′-(1, 4-phenylene)bis(3-
methylthiourea) 2. However, bis thiourea 2 was formed and
removed by extraction with HCl (Scheme 1).
Anti‑biofilm assessment (ABF)
Anti-biofilm effect of the synthesized compounds was
studied by microtiter plate adhesion assessment. Biofilm
formation in this assay was determined by a literature
method [10]. In this study, a culture of the bacteria and
fungi was grown over night in the broth media. Then, the
cultures were diluted 1:100 into fresh medium for biofilm
assessments. 100 µL of the dilution was added on well in
a 96-well dish. For quantitative assays, we typically use 4
reproduced wells for each treatment. The microtiter plate
was incubated for 24 h at 37 °C. After incubation, cells
were unloaded by turning the plate over and shaking out the
liquid. Finally, the biofilms were discolored by the 0.1%
The synthesis of acridinyl thiourea 3 was performed
by the three-component reaction of dimedone, aromatic
Scheme 2 Synthesis of acridi-
nyl thiourea derivatives
1 3

J IRAN CHEM SOC
Scheme 3 Synthesis of thia-
zolidin-4-ones from acridinyl
thioureas 3
aldehydes and 1-(4-Amino-phenyl)-3-methyl-thiourea 1 in
DMF as solvent. One drop of HCl was used as a cheap and
easy available catalyst (Scheme 2).
To obtain the optimized temperature, the reaction was
performed at 60, 80, 100 and 120 °C. Best results were
obtained at 100 °C.
The scope and generality of this reaction was checked
by performing the reaction with aromatic aldehydes hav-
ing electron-donating and electron-withdrawing groups. As
Table 1 shows, electron-donating groups decrease the reac-
tion rate.
Antimicrobial activities
The antibacterial and antifungal activity of the synthe-
sized compounds was tested in vitro against the following
bacterial strains: two Gram-positive bacteria, including
Staphylococcus aureus PTCC1112, Micrococcus luteus
PTCC1110, and three Gram-negative bacteria, Escheri-
chia coli PTCC 1330, Pseudomonas aeruginosa and Kleb-
siella pneumoniae, and one fungi strain, Candida albicans
PTCC5011. To determine the antimicrobial activity of the
target compounds, the disk diffusion test was employed
according to NCCLS guidelines [13] (Table 3).
Control positive tests were accomplished under simi-
lar conditions by using trimethoprim/sulfamethoxazole
(SXT), ciprofloxacin for antibacterial activity and flu-
conazole for antifungal activity as standard drugs. Sterile
disks impregnated with DMSO were employed as a nega-
tive control.
The structures of compounds 3a–e were designated
on the basis of their spectral data and elemental analysis.
Compound 3a displayed a broad peak in the IR spectrum
for NH protons at 3323 cm−1. The 1H NMR spectrum of 3a
shows two singlet for methyl protons at 0.72 and 0.82 ppm.
A distinct peak was seen in 5.07 ppm for aliphatic CH
proton.
In the 13C NMR spectrum of 3a, signals corresponding
to thiourea and carbonyl group were observed at 180.9 and
195.0 ppm.
The results of the antibacterial and antifungal activities
are presented in Table 3.
In this study, acridinyl thioureas 3 (except 3b) were
found to exhibit antibacterial activity only against Gram-
positive strains Staphylococcus aureus or Micrococcus
luteus, while some of the thiazolidinones 4 showed broader
antibacterial spectrum and were effective on Gram-pos-
itive and Gram-negative bacteria. It is also noteworthy to
mention that the compounds 4b and 4d showed antifungal
activity whereas related thioureas showed no antifungal
activity.
Minimum inhibitory concentration (MIC) was deter-
mined for the compounds showing antimicrobial activity.
The lowest concentration showing no growth was taken as
the MIC.
The cycloaddition of these stable acridinyl thiourea
derivatives 3, with DAAD resulted in the formation of thia-
zolidin-4-ones 4a–j with good yields (Scheme 3).
The reaction was performed at room temperature with-
out any catalyst, the results are summarized in Table 2.
The chemical structure of thiazolidinones 4a–j was
clarified from their IR, 1H NMR and 13C NMR spec-
tra. The IR spectrum of 4a showed strong bands at 1637
1
and 1728 cm−1 related to carbonyl groups. The H NMR
spectrum of 4a showed clearly the presence of OCH3 at
3.82 ppm. The singlet sharp peak at 6.93 ppm was attrib-
uted to the vinyl CH proton.
The 13C NMR spectrum of 4a supported the pres-
ence of ester and amide carbonyl groups at the 164.3 and
165.6 ppm.
Anti-biofilm effect was another factor which was inves-
tigated for the active compounds.
1 3

J IRAN CHEM SOC
Table 1 Synthesis of 1,8-dioxo octahydroacridine functionalized
thioureas 3
Table 2 Thiazolidin-4-one derivatives 4 from 1,8-dioxo octahy-
droacridinyl thioureas 3 and DAAD
Compounds
Structure
Time (min)
30
Yield (%)
61
Compound
Structure
Time (h)
4
Yield (%)
70
3a
4a
O
O
O
O
N
N
S
NH
NH
N
N
S
O
O
Cl
O
3b
30
70
4b
4
68
O
O
O
O
N
N
S
NH
N
N
NH
S
O
OMe
3c
75
90
O
O
O
O
Cl
4c
4
80
N
O
O
N
N
S
NH
NH
NO2
3d
30
80
N
S
O
O
O
O
O
N
Cl
4d
4
85
O
O
S
NH
NH
N
N
OH
3e
60
62
OH
O
O
N
S
O
O
N
O
S
NH
NH
1 3

J IRAN CHEM SOC
Table 2 continued
Table 2 continued
Compound
Structure
Time (h)
4
Yield (%)
65
Compound
Structure
Time (h)
6
Yield (%)
88
OMe
OH
4e
4i
OH
O
O
O
O
N
N
N
N
S
N
N
S
O
O
O
O
O
O
OMe
OH
4f
4
60
4j
6
82
OH
O
O
O
O
N
N
N
N
S
N
N
S
O
O
O
O
O
O
NO2
4 g
6
70
O
O
A biofilm is any group of microorganisms in which cells
stick to each other and often these cells stick to a surface.
Anti-biofilm effect of the synthesized compounds was
investigated by microtiter plate adhesion assay. A literature
method was used for the determination of anti-biofilm for-
mation [10].
N
N
S
The results of MIC and anti-biofilm formation (ABF)
are reported in Table 4.
N
O
O
O
NO2
4 h
6
75
Conclusion
O
O
In conclusion, a series of novel 1,8-dioxo octahydroacrid-
ine functionalized thiourea and thiazolidinone derivatives
were synthesized and their antimicrobial activities have
been evaluated. Some of these compounds (4d and 4j)
showed potent inhibition against clinical strains such as
Pseudomonas aeruginosa and Klebsiella pneumonia that
are resistant to SXT and ciprofloxacin.
N
N
S
N
O
O
O
1 3

J IRAN CHEM SOC
Table 3 Antimicrobial effect of acridinyl thioureas 3 and thiazolidinones 4
Compound
Inhibition zone diameter (mm)
S. aureus PTCC1112 M. luteus PTCC1110 E. coli PTCC1330 P. aeruginosa* K. pneumoniae* C. albicans PTCC5011
3a
3b
3c
12
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
12
0
0
–
0
0
0
0
0
0
0
0
19
0
0
0
0
0
0
0
0
–
0
0
0
0
0
22
19
21
0
0
0
3d
3e
0
0
0
0
0
0
4a
4b
4c
12
0
0
0
0
0
21
0
16
21
0
0
0
4d
4e
0
11
0
19
0
0
4f
0
0
0
0
4 g
4 h
4i
16
0
0
0
0
0
0
0
16
0
0
0
0
4j
0
0
0
SXT
18
30
31
–
22.5
27
–
0
Ciprofloxacin 25
FL(25 µg)
0
–
32
* Isolated clinical samples
Table 4 Comparison of ABF
(mg/mL) and MIC (mg/mL) of
the acridinyl thioureas 2 and
thiazolidinones 3
Compounds S. aureus
M. luteus
PTCC1110
E. coli
PTCC1330
P. aerugi-
nosa*
K. pneumo- C. albicans
PTCC1112
niae*
PTCC5011
ABF MIC ABF MIC ABF MIC ABF MIC ABF MIC ABF
MIC
3a
3c
3d
3e
4c
4d
4a
4b
4 g
4i
1.56
–
3.125
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
0.097 6.25
0.049 1.56
0.097 1.56
–
–
–
–
–
–
–
–
–
–
0.39
1.56
–
6.25
6.25
6.25
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
0.049 6.25
–
–
6.25 12.5 ND** 6.25
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
0.78
3.125
–
–
ND
–
6.25
–
3.125
–
–
–
–
–
–
–
–
–
–
–
0.195 6.25
–
–
–
4j
–
–
ND
6.25
–
* Isolated clinical samples
** Not Determined
Acknowledgements This work was supported by grants from the
Research Council of Shahid Bahonar University of Kerman.
2. S. Girault, P. Grellier, A. Berecibar, L. Maes, E. Mouray, P. Lem-
ière, M.A. Debreu, E. Davioud-Charvet, C. Sergheraert, J. Med.
Chem. 43, 2646 (2000)
3. J.X. Kelly, M.J. Smilkstein, R. Brun, S. Wittlin, R.A. Cooper,
K.D. Lane, A. Janowsky, R.A. Johnson, R.A. Dodean, R. Winter,
D.J. Hinrichs, M.K. Riscoe, Nature 459, 270 (2009)
4. U. Thuli, B. Testa, Biochem. Pharmacol. 47, 2307 (1994)
5. M. Demeunynck, F. Charmantray, A. Martelli, Curr. Pharm. Des.
7, 1703 (2001)
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