# Amidine Sulfonamides and Benzene Sulfonamides: Synthesis and Their Biological Evaluation

Authors: Muhammad Abdul Qadir; Mahmood Ahmed; Hina Aslam; Sadia Waseem; Muhammad Imtiaz Shafiq
Journal: Journal of Chemistry
 (2015)

---

## Abstract

New amidine and benzene sulfonamide derivatives were developed and structures of the new products were confirmed by elemental and spectral analysis (FT-IR, ESI-MS,1HNMR, and 13CNMR). In vitro, developed compounds were screened for their antibacterial and antifungal activities against medically important bacterial strains, namely, S. aureus, B. subtilis, and E. coli, and fungi, namely, A. flavus, A. parasiticus, and A. sp. The antibacterial and antifungal activities have been determined by measuring MIC values (μg/mL) and zone of inhibitions (mm). Among the tested compounds, it was found that compounds 3b, 9a, and 9b have most potent activity against S. aureus, A. flavus, and A. parasiticus, respectively, and were found to be more active than sulfamethoxazole and itraconazole with MIC values 40 μg/mL. In contrast, all the compounds were totally inactive against the A. sp. except 10b and 15b to show activity to some extent.


---

## Body

## 1. Introduction

Sulfonamides are basis of several drug groups, known as sulfa drugs. Any compound that has sulfonamide moiety (SO2NH2) in its structure is referred to as sulfonamide. They comprise substantial class of pharmaceutical drugs, containing various kinds of pharmacological agents having antitumor [1], antibacterial [2], anticarbonic anhydrase [3, 4], diuretic [5, 6], hypoglycemic [7], and protease inhibitory activity [8–10] or antithyroid activity [11] among others. Sulfonamides are mostly used to treat the bacterial infectious cells because they do not significantly affect the antigenic properties of the infective organism or the development of specific antibodies [12]. Bacteria have liability to acquire resistance against sulfonamides by changing their cell wall permeability, enhancing essential metabolites production, or increasing production of enzyme [13]. In this way sulfonamides become ineffective to inhibit their production. But their ineffectiveness in drug therapy can be abstained, due to inductive effect of SO2 group. Sulfonamides having first p
K
a value around 10 are less soluble in water; therefore, they may readily crystalize in kidney but with advancement in medical science, and new sulfonamides have been synthesized having lower p
K
a value (5-6) to avoid crystallization in kidney [14]. The compounds having pyridine and amide functional group exhibit various biological activities like antifungal and antibacterial. So these biological activities encourage us to synthesize the sulfonamides containing such important functional groups [15–18]. The motivation behind this research work was to synthesize some novel sulfonamides (Schemes 1–4) having antimicrobial properties. Different amines were chosen and reacted with sulfonyl chlorides. As a result of substitution, different functional groups were added and resulting compounds exhibited antibacterial and antifungal activities.Scheme 1
Amidine sulfonamides.Scheme 2
Benzene sulfonamides (series 1).Scheme 3
Benzene sulfonamides (series 2).Scheme 4


## 2. Experimental

### 2.1. Chemistry

Chemicals used in present work were of analytical grade obtained from E-Merck (Germany), Sigma Aldrich (USA), and BDH (UK) without further purification to synthesize desired compounds, and high purity water (0.01μS/cm) was prepared in our own laboratory using Milli-Q purification system (USA). Alpha IR spectrometer (FTIR-ATR) and NMR spectrometer, Bruker, were used to record the IR and 1HNMR (500 MHz) and 13CNMR (125 MHz) spectra, respectively. PG-T80+ UV-Vis spectrophotometer (UK) and Flash HT Plus elemental analyzer (Thermo Scientific, UK) were used for λ
m
a
x, and concentration of hydrogen (H), carbon (C), nitrogen (N), and sulfur (S) of synthesized compounds, respectively, while the melting point was measured by Gallenkamp apparatus. JMS-HX-110 spectrometer with electron spray ionization (ESI) interface was used for mass spectra. The 1HNMR and 13CNMR spectra of all the synthesized compounds were measured using MeOD and concentration of all the compounds was 10–20 mg in 0.8–1.0 mL of solvent. Purification and progress of the synthesized compounds were confirmed on precoated TLC silica plate (Merck-Germany).


### 2.2. Antimicrobial Assay

Escherichia coliATCC 25922,Staphylococcus aureusATCC 25923,Bacillus subtilisATCC 6633,Aspergillus flavus ATCC 9643,Aspergillus parasiticusATCC 15517, andAcremoniumsp. ATCC 200667 were collected from Mycology Department, University of Punjab, Lahore, Pakistan, and were maintained in tryptic soy agar (TSA) and potato dextrose agar (PDA) medium, respectively, slants at 5°C until use. A series of four 2-fold dilutions (320, 160, 80, and 40 μg/mL) were made from stock solution of 640 μg/mL in dimethyl sulphoxide (DMSO). All the dilutions were made sterile in an autoclave at 121°C for 30 min with 15 psi pressure after filtration through 0.22 μm membrane filter. The minimal inhibitory concentration (MIC) was reported as absence of no observable growth by the lowest concentration of tested compounds after twofold serial dilution. Five individually numbered test tubes with screw caps were sterilized. Tube 1 was filled with 2 mL of tryptic soy broth culture media including the stock solution of synthesized compounds. 1.0 mL of this solution was introduced into 2 tubes and diluted with 1.0 mL culture media and we repeated the procedure up to tube 5. The tubes were incubated at 25°C for 72 hrs. Ciprofloxacin and sulfamethoxazole (sulfa drug) were used as reference (positive control to check the sensitivity of tested bacterial strains). 1
–
3
×
10
8 cfu/mL of each of Gram negativeE. coliand Gram positiveS. aureusandB. subtilis was obtained after adjusting the optical density of inoculum at 0.2–0.3 and 0.3–0.4 (620 nm), respectively, while fungal suspension (A. flavus, A. parasiticus,andA.sp.) with cell density of 105 cfu/mL was studied in present work and the itraconazole was used as reference antifungal agent. All the compounds and reference solutions were applied (50 μL) onto a 6 mm sterile filter paper disc separately and the inoculated plates incubated at 37°C for 24 hrs. The zones of inhibition (mm) were measured and we evaluated the antibacterial activities.


### 2.3. General Procedure for Synthesis of Sulfonamides

A simple method in aqueous media under dynamic pH control is adopted for synthesis of sulfonamides. Filtration after acidification is involved for isolation of products [19–21]. All the amines were weighed accurately and dissolved completely by addition of distilled water by constant stirring using magnetic stirrer. The pH of the reaction contents was strictly monitored and maintained at 8–10 at regular intervals during the experimental reaction using Na2CO3 solution (1 M). Then benzene sulfonyl chloride or p-toluene sulphonyl chloride was accurately weighed and added carefully into the above solution. The reaction was carried in round bottom flask equipped with magnetic stirrer. During stirring sulphonyl chloride initially floats on the surface and the completion of reaction was examined by the change in pH value due to formation of HCl by the consumption of sulphonyl chlorides during the reaction. On completion of the reaction pH was adjusted at 2-3 using HCl solution (2 M). The precipitates formed were filtered through Whatman filter paper number 42, washed several times with distilled water, and recrystallized using methanol and dried using rotary evaporator.


### 2.4. N-{Imino[(phenylsulfonyl)amino]methyl}-N-methylglycine (3a, C10H13N3O4S)

Yield: 397.9 mg (64.7%); m.p.: 172–174°C; TLC:R
f
=
0.72 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
-
=
3215 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 3084 (C-H
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 1768 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1707 (C=N
i
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1438 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1033 (S=O
s
t
r
e
t
c
h
i
n
g), 1165 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1458 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 706 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 208 (25050) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ
=
9.91 (br, s, 1H, NH), 7.98 (d, J
=
7.48 Hz, 1H, CH), 7.68 (t, J
=
7.59 Hz, 1H, CH), 7.56 (d, J
=
7.63 Hz, 1H, CH), 4.71 (d, J
=
13.16 Hz, 2H, CH2), 3.15 (s, 3H, CH3); 13CNMR (125 MHz, MeOD) δ
=
168 (C-16), 155 (C-11), 141 (C-1), 135 (C-4), 129 (C-3), 51 (C-15), 35 (C-14); ESI-MS:m/z = 273.38 [M + 2]+, 271.31 [M]+.


### 2.5. N-(Imino{[(4 methylphenyl)sulfonyl]amino}methyl)-N-methylglycine (3b, C11H15N3O4S)

Yield: 779.9 mg (82.7%); m.p.: 185–187°C; TLC:R
f
=
0.64 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3224 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 2992 (C-H
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 1767 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1699 (C=N
i
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1438 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1028 (S=O
s
t
r
e
t
c
h
i
n
g), 1199 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1498 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 701 (Ø-S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 222 (22500) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ
=
9.96 (br, s, 1H, NH), 7.71 (s, 1H, CH), 7.38 (d, J
=
8.11 Hz, 1H, CH), 4.68 (s, 2H, CH2), 3.15 (s, 3H, CH3), 2.26 (s, 3H, CH3); 13CNMR (125 MHz, MeOD) δ
=
168 (C-17), 156 (C-12), 143 (C-1), 138 (C-4), 129 (C-2), 52 (C-16), 35 (C-15), 22 (C-7); ESI-MS:m/z = 287.39 [M + 2]+, 285.34 [M]+.


### 2.6. N-[[Bis(phenylsulfonyl)amino](imino)methyl]-N-methylglycine (4a, C16H17N3O6S2)

Yield: 931.8 mg (81.3%); m.p.: 210–212°C; TLC:R
f
=
0.67 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3062 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1767 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1621 (C=N
i
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1445 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1037 (S=O
s
t
r
e
t
c
h
i
n
g), 1163 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1445 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 689 (Ø-S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 210 (17250) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 10.86 (br, s, 1H, NH), 8.21 (t, J
=
7.61 Hz, 1H, CH), 8.08 (d, J
=
7.61 Hz, 1H, CH), 7.93 (s, 1H, CH), 4.75 (s, 2H, CH2), 3.16 (s, 3H, CH3); 13CNMR (125 MHz, MeOD) δ = 168 (C-25), 156 (C-13), 141 (C-1), 132 (C-4), 131 (C-5), 53 (C-24), 37 (C-23); ESI-MS:m/z= 413.59 [M + 2]+, 411.48 [M]+.


### 2.7. N-[{Bis[(4-methylphenyl)sulfonyl]amino}(imino)methyl]-N-methylglycine (4b, C18H21N3O6S2)

Yield: 872.1 mg (82.2%); m.p.: 195–197°C; TLC:R
f
=
0.63 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
-
=
3265 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1707 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1600 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1660 (C=N
i
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1399 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1043 (S=O
s
t
r
e
t
c
h
i
n
g), 1182 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1445 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 685 (Ø-S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 222 (19000) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 10.76 (br, s, 1H, NH), 7.81 (d, J
=
8.11 Hz, 1H, CH), 7.78 (d, J
=
8.14 Hz, 1H, CH), 4.73 (s, 2H, CH2), 3.15 (s, 3H, CH3), 2.46 (s, 3H, CH3); 13CNMR (500 MHz, MeOD) δ = 168 (C-27), 156 (C-14), 143 (C-1), 139 (C-4), 132 (C-6), 53 (C-26), 37 (C-24), 21 (C-25); ESI-MS:m/z = 441.53 [M + 2]+, 439.58 [M]+.


### 2.8. N-{Imino[[(4-methylphenyl)sulfonyl](phenylsulfonyl) amino]methyl}-N-methylglycine (6a, C17H19N3O6S2)

Yield: 626.4 mg (70.6%); m.p.: 182–184°C; TLC:R
f
=
0.61 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3277 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1707 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1599 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1659 (C=N
i
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1399 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1040 (S=O
s
t
r
e
t
c
h
i
n
g), 1185 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1444 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 684 (Ø-S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 218 (26150) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 10.79 (br, s, 1H, NH), 8.21 (d, J
=
7.61 Hz, 1H, CH), 8.10 (s, H, CH), 7.91 (s, H, CH), 7.87 (d, J
=
8.11 Hz, 1H, CH), 7.73 (s, H, CH), 7.73 (d, J
=
8.01 Hz, 1H, CH), 4.73 (s, 2H, CH2), 3.15 (s, 3H, CH3), 2.44 (s, 3H, CH3); (125 MHz, MeOD) δ = 168 (C-26), 156 (C-14), 143 (C-1), 141 (C-17), 132 (C-20), 131 (C-2), 129 (C-3), 53 (C-25), 39 (C-24), 23 (C-7); ESI-MS:m/z = 427.53 [M + 2]+, 425.48 [M]+.


### 2.9. N-(Pyridin-2-yl)benzene Sulfonamide (9a, C11H10N2O2S)

Yield: 869.6 mg (83.1%); m.p.: 145–147°C; TLC:R
f
=
0.61 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3367 (N-H
a
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1666 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1024 (S=O
s
t
r
e
t
c
h
i
n
g), 1177 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1445 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 687 (Ø-S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 230 (43800) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 11.49 (br, s, 1H, NH), 7.91 (d, J
=
5.21 Hz, 1H, CH), 7.81 (d, J
=
7.61 Hz, 1H, CH), 7.65 (t, J
=
8.31 Hz, 1H, CH), 7.61 (t, J
=
7.51 Hz, 1H, CH), 7.55 (t, J
=
7.61 Hz, 1H, CH), 7.25 (t, J
=
7.21 Hz, 1H, CH), 7.15 (d, J
=
8.39 Hz, 1H, CH); 13CNMR (125 MHz, MeOD) δ = 148 (C-2), 145 (C-6), 140 (C-11), 137 (C-4), 132 (C-14), 129 (C-13), 127 (C-12), 115 (C-5), 112 (C-3); ESI-MS:m/z = 236.31 [M + 2]+, 234.28 [M]+.


### 2.10.
4-Methyl-N-(pyridin-2-yl)benzene Sulfonamide (9b, C12H12N2O2S)

Yield: 935.6 mg (82.1%); m.p.: 178–180°C; TLC:R
f
=
0.72 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3328 (N-H
a
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1665 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1019 (S=O
s
t
r
e
t
c
h
i
n
g), 1161 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1455 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 680 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 224 (15380) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 11.43 (br, s, 1H, NH), 7.97 (d, J
=
8.11 Hz, 1H, CH), 7.61 (d, J
=
8.31 Hz, 1H, CH), 7.25 (t, J
=
7.21 Hz, 1H, CH), 7.20 (s, 1H, CH), 7.11 (t, J
=
8.41 Hz, 1H, CH), 7.15 (d, J
=
8.39 Hz, 1H, CH), 2.48 (s, 3H, CH3); 13CNMR (125 MHz, MeOD) δ = 148 (C-2), 145 (C-6), 143 (C-14), 137 (C-4), 129 (C-13), 115 (C-5), 111 (C-3), 21 (C-17); ESI-MS:m/z = 250.35 [M + 2]+, 248.30 [M]+.


### 2.11. N-(Phenylsulfonyl)-N-(pyridin-2-yl)benzene Sulfonamide (10a, C17H14N2O4S2)

Yield: 909.8 mg (71.7%); m.p.: 166–168°C; TLC:R
f
=
0.62 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3348 (N-H
a
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1619 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1030 (S=O
s
t
r
e
t
c
h
i
n
g), 1186 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1445 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 688 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 215 (12830) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 8.13 (m, 1H, CH), 8.11 (m, 1H, CH), 7.95 (m, 1H, CH), 7.88 (m, 1H, CH), 7.81 (m, 1H, CH), 7.65 (qd, J
=
8.39 Hz, 1.21 Hz, 1H, CH), 7.48 (qd, J
=
7.29 Hz, 5.21 Hz, 1H, CH); 13CNMR (125 MHz, MeOD) δ = 148 (C-6), 142 (C-13), 138 (C-2), 131 (C-16), 130 (C-14), 117 (C-5), 113 (C-3); ESI-MS:m/z = 376.45 [M + 2]+, 374.44 [M]+.


### 2.12.
4-Methyl-N-(phenylsulfonyl)-N-(pyridin-2-yl)benzene Sulfonamide (10b, C19H18N2O4S2)

Yield: 1140.5 mg (84.3%); m.p.: 164–166°C; TLC:R
f
=
0.68 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3348 (N-H
a
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1621 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1027 (S=O
s
t
r
e
t
c
h
i
n
g), 1162 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1445 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 681 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 222 (13855) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 8.19 (s, H, CH), 8.02 (d, J
=
8.09 Hz, 1H, CH), 7.87 (t, J
=
8.41 Hz, 1H, CH), 7.68 (d, J
=
8.11 Hz, 1H, CH), 7.61 (d, J
=
8.37 Hz, 1H, CH), 7.55 (d, J
=
7.27 Hz, 1H, CH), 2.46 (s, 3H, CH3); 13CNMR (125 MHz, MeOD) δ = 148 (C-6), 138 (C-2), 132 (C-15), 117 (C-5), 113 (C-3), 22 (C-27); ESI-MS:m/z = 404.55 [M + 2]+, 402.51 [M]+.


### 2.13.
4-Methyl-N-(phenylsulfonyl)-N-(pyridin-2-yl)benzene Sulfonamide (12a, C18H16N2O4S2)

Yield: 529.5 mg (65.1%); m.p.: 188–190°C; TLC:R
f
=
0.76 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3280 (N-H
a
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1620 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1021 (S=O
s
t
r
e
t
c
h
i
n
g), 1158 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1445 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 682 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 220 (42550) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 8.15 (d, J
=
7.69 Hz, 1H, CH), 8.07 (d, J
=
8.11 Hz, 1H, CH), 7.98 (d, J
=
7.61 Hz, 1H, CH), 7.91 (t, J
=
8.37 Hz, 1H, CH), 7.65 (d, J
=
8.17 Hz, 1H, CH), 7.51 (d, J
=
7.17 Hz, 1H, CH), 7.45 (d, J
=
7.17 Hz, 1H, CH), 2.44 (s, 3H, CH3); 13CNMR (125 MHz, MeOD) δ = 147 (C-6), 138 (C-2), 132 (C-15), 117 (C-5), 112 (C-3), 21 (C-27); ESI-MS:m/z = 390.53 [M + 2]+, 388.49 [M]+.


### 2.14. N-Methyl-N-(phenylsulfonyl)alanine (15a, C10H13NO4S)

Yield: 786.1 mg (51.7%); m.p.: 132–134°C; TLC:R
f
=
0.72 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3215 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1743 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1444 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1041 (S=O
s
t
r
e
t
c
h
i
n
g), 1183 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1444 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 688 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 215 (13070) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 7.73 (d, J
=
7.69 Hz, 1H, CH), 7.53 (d, J
=
7.51 Hz, 1H, CH), 7.36 (t, J
=
7.61 Hz, 1H, CH), 4.51 (q, J
=
7.17 Hz, 1H, CH), 3.75 (br, s, 1H, OH), 2.71 (s, 3H, CH3), 1.11 (d, J
=
7.17 Hz, 3H, CH3); 13CNMR (125 MHz, MeOD) δ = 178 (C-14), 138 (C-1), 131 (C-4), 62 (C-12), 29 (C-11), 15 (C-13); ESI-MS:m/z = 245.38 [M + 2]+, 243.35 [M]+.


### 2.15. N-Methyl-N-[(4-methylphenyl)sulfonyl]alanine (15b, C11H15NO4S)

Yield: 910.9 mg (63.6%); m.p.: 140–142°C; TLC:R
f
=
0.70 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3268 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1710 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1449 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1054 (S=O
s
t
r
e
t
c
h
i
n
g), 1146 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1422 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 677 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 220 (17250) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 7.69 (d, J
=
8.09 Hz, 1H, CH), 7.32 (d, J
=
7.91 Hz, 1H, CH), 4.48 (t, J
=
7.17 Hz, 1H, CH), 3.75 (br, s, 1H, OH), 2.69 (s, 3H, CH3), 2.39 (s, 3H, CH3), 1.08 (d, J
=
7.17 Hz, 3H, CH3); 13CNMR (125 MHz, MeOD) δ = 178 (C-14), 138 (C-1), 133 (C-4), 129 (C-5), 61 (C-12), 29 (C-11), 15 (C-13); ESI-MS:m/z = 259.38 [M + 2]+, 257.35 [M]+.


## 2.1. Chemistry

Chemicals used in present work were of analytical grade obtained from E-Merck (Germany), Sigma Aldrich (USA), and BDH (UK) without further purification to synthesize desired compounds, and high purity water (0.01μS/cm) was prepared in our own laboratory using Milli-Q purification system (USA). Alpha IR spectrometer (FTIR-ATR) and NMR spectrometer, Bruker, were used to record the IR and 1HNMR (500 MHz) and 13CNMR (125 MHz) spectra, respectively. PG-T80+ UV-Vis spectrophotometer (UK) and Flash HT Plus elemental analyzer (Thermo Scientific, UK) were used for λ
m
a
x, and concentration of hydrogen (H), carbon (C), nitrogen (N), and sulfur (S) of synthesized compounds, respectively, while the melting point was measured by Gallenkamp apparatus. JMS-HX-110 spectrometer with electron spray ionization (ESI) interface was used for mass spectra. The 1HNMR and 13CNMR spectra of all the synthesized compounds were measured using MeOD and concentration of all the compounds was 10–20 mg in 0.8–1.0 mL of solvent. Purification and progress of the synthesized compounds were confirmed on precoated TLC silica plate (Merck-Germany).


## 2.2. Antimicrobial Assay

Escherichia coliATCC 25922,Staphylococcus aureusATCC 25923,Bacillus subtilisATCC 6633,Aspergillus flavus ATCC 9643,Aspergillus parasiticusATCC 15517, andAcremoniumsp. ATCC 200667 were collected from Mycology Department, University of Punjab, Lahore, Pakistan, and were maintained in tryptic soy agar (TSA) and potato dextrose agar (PDA) medium, respectively, slants at 5°C until use. A series of four 2-fold dilutions (320, 160, 80, and 40 μg/mL) were made from stock solution of 640 μg/mL in dimethyl sulphoxide (DMSO). All the dilutions were made sterile in an autoclave at 121°C for 30 min with 15 psi pressure after filtration through 0.22 μm membrane filter. The minimal inhibitory concentration (MIC) was reported as absence of no observable growth by the lowest concentration of tested compounds after twofold serial dilution. Five individually numbered test tubes with screw caps were sterilized. Tube 1 was filled with 2 mL of tryptic soy broth culture media including the stock solution of synthesized compounds. 1.0 mL of this solution was introduced into 2 tubes and diluted with 1.0 mL culture media and we repeated the procedure up to tube 5. The tubes were incubated at 25°C for 72 hrs. Ciprofloxacin and sulfamethoxazole (sulfa drug) were used as reference (positive control to check the sensitivity of tested bacterial strains). 1
–
3
×
10
8 cfu/mL of each of Gram negativeE. coliand Gram positiveS. aureusandB. subtilis was obtained after adjusting the optical density of inoculum at 0.2–0.3 and 0.3–0.4 (620 nm), respectively, while fungal suspension (A. flavus, A. parasiticus,andA.sp.) with cell density of 105 cfu/mL was studied in present work and the itraconazole was used as reference antifungal agent. All the compounds and reference solutions were applied (50 μL) onto a 6 mm sterile filter paper disc separately and the inoculated plates incubated at 37°C for 24 hrs. The zones of inhibition (mm) were measured and we evaluated the antibacterial activities.


## 2.3. General Procedure for Synthesis of Sulfonamides

A simple method in aqueous media under dynamic pH control is adopted for synthesis of sulfonamides. Filtration after acidification is involved for isolation of products [19–21]. All the amines were weighed accurately and dissolved completely by addition of distilled water by constant stirring using magnetic stirrer. The pH of the reaction contents was strictly monitored and maintained at 8–10 at regular intervals during the experimental reaction using Na2CO3 solution (1 M). Then benzene sulfonyl chloride or p-toluene sulphonyl chloride was accurately weighed and added carefully into the above solution. The reaction was carried in round bottom flask equipped with magnetic stirrer. During stirring sulphonyl chloride initially floats on the surface and the completion of reaction was examined by the change in pH value due to formation of HCl by the consumption of sulphonyl chlorides during the reaction. On completion of the reaction pH was adjusted at 2-3 using HCl solution (2 M). The precipitates formed were filtered through Whatman filter paper number 42, washed several times with distilled water, and recrystallized using methanol and dried using rotary evaporator.


## 2.4. N-{Imino[(phenylsulfonyl)amino]methyl}-N-methylglycine (3a, C10H13N3O4S)

Yield: 397.9 mg (64.7%); m.p.: 172–174°C; TLC:R
f
=
0.72 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
-
=
3215 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 3084 (C-H
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 1768 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1707 (C=N
i
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1438 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1033 (S=O
s
t
r
e
t
c
h
i
n
g), 1165 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1458 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 706 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 208 (25050) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ
=
9.91 (br, s, 1H, NH), 7.98 (d, J
=
7.48 Hz, 1H, CH), 7.68 (t, J
=
7.59 Hz, 1H, CH), 7.56 (d, J
=
7.63 Hz, 1H, CH), 4.71 (d, J
=
13.16 Hz, 2H, CH2), 3.15 (s, 3H, CH3); 13CNMR (125 MHz, MeOD) δ
=
168 (C-16), 155 (C-11), 141 (C-1), 135 (C-4), 129 (C-3), 51 (C-15), 35 (C-14); ESI-MS:m/z = 273.38 [M + 2]+, 271.31 [M]+.


## 2.5. N-(Imino{[(4 methylphenyl)sulfonyl]amino}methyl)-N-methylglycine (3b, C11H15N3O4S)

Yield: 779.9 mg (82.7%); m.p.: 185–187°C; TLC:R
f
=
0.64 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3224 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 2992 (C-H
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 1767 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1699 (C=N
i
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1438 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1028 (S=O
s
t
r
e
t
c
h
i
n
g), 1199 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1498 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 701 (Ø-S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 222 (22500) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ
=
9.96 (br, s, 1H, NH), 7.71 (s, 1H, CH), 7.38 (d, J
=
8.11 Hz, 1H, CH), 4.68 (s, 2H, CH2), 3.15 (s, 3H, CH3), 2.26 (s, 3H, CH3); 13CNMR (125 MHz, MeOD) δ
=
168 (C-17), 156 (C-12), 143 (C-1), 138 (C-4), 129 (C-2), 52 (C-16), 35 (C-15), 22 (C-7); ESI-MS:m/z = 287.39 [M + 2]+, 285.34 [M]+.


## 2.6. N-[[Bis(phenylsulfonyl)amino](imino)methyl]-N-methylglycine (4a, C16H17N3O6S2)

Yield: 931.8 mg (81.3%); m.p.: 210–212°C; TLC:R
f
=
0.67 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3062 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1767 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1621 (C=N
i
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1445 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1037 (S=O
s
t
r
e
t
c
h
i
n
g), 1163 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1445 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 689 (Ø-S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 210 (17250) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 10.86 (br, s, 1H, NH), 8.21 (t, J
=
7.61 Hz, 1H, CH), 8.08 (d, J
=
7.61 Hz, 1H, CH), 7.93 (s, 1H, CH), 4.75 (s, 2H, CH2), 3.16 (s, 3H, CH3); 13CNMR (125 MHz, MeOD) δ = 168 (C-25), 156 (C-13), 141 (C-1), 132 (C-4), 131 (C-5), 53 (C-24), 37 (C-23); ESI-MS:m/z= 413.59 [M + 2]+, 411.48 [M]+.


## 2.7. N-[{Bis[(4-methylphenyl)sulfonyl]amino}(imino)methyl]-N-methylglycine (4b, C18H21N3O6S2)

Yield: 872.1 mg (82.2%); m.p.: 195–197°C; TLC:R
f
=
0.63 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
-
=
3265 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1707 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1600 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1660 (C=N
i
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1399 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1043 (S=O
s
t
r
e
t
c
h
i
n
g), 1182 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1445 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 685 (Ø-S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 222 (19000) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 10.76 (br, s, 1H, NH), 7.81 (d, J
=
8.11 Hz, 1H, CH), 7.78 (d, J
=
8.14 Hz, 1H, CH), 4.73 (s, 2H, CH2), 3.15 (s, 3H, CH3), 2.46 (s, 3H, CH3); 13CNMR (500 MHz, MeOD) δ = 168 (C-27), 156 (C-14), 143 (C-1), 139 (C-4), 132 (C-6), 53 (C-26), 37 (C-24), 21 (C-25); ESI-MS:m/z = 441.53 [M + 2]+, 439.58 [M]+.


## 2.8. N-{Imino[[(4-methylphenyl)sulfonyl](phenylsulfonyl) amino]methyl}-N-methylglycine (6a, C17H19N3O6S2)

Yield: 626.4 mg (70.6%); m.p.: 182–184°C; TLC:R
f
=
0.61 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3277 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1707 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1599 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1659 (C=N
i
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1399 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1040 (S=O
s
t
r
e
t
c
h
i
n
g), 1185 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1444 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 684 (Ø-S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 218 (26150) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 10.79 (br, s, 1H, NH), 8.21 (d, J
=
7.61 Hz, 1H, CH), 8.10 (s, H, CH), 7.91 (s, H, CH), 7.87 (d, J
=
8.11 Hz, 1H, CH), 7.73 (s, H, CH), 7.73 (d, J
=
8.01 Hz, 1H, CH), 4.73 (s, 2H, CH2), 3.15 (s, 3H, CH3), 2.44 (s, 3H, CH3); (125 MHz, MeOD) δ = 168 (C-26), 156 (C-14), 143 (C-1), 141 (C-17), 132 (C-20), 131 (C-2), 129 (C-3), 53 (C-25), 39 (C-24), 23 (C-7); ESI-MS:m/z = 427.53 [M + 2]+, 425.48 [M]+.


## 2.9. N-(Pyridin-2-yl)benzene Sulfonamide (9a, C11H10N2O2S)

Yield: 869.6 mg (83.1%); m.p.: 145–147°C; TLC:R
f
=
0.61 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3367 (N-H
a
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1666 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1024 (S=O
s
t
r
e
t
c
h
i
n
g), 1177 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1445 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 687 (Ø-S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 230 (43800) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 11.49 (br, s, 1H, NH), 7.91 (d, J
=
5.21 Hz, 1H, CH), 7.81 (d, J
=
7.61 Hz, 1H, CH), 7.65 (t, J
=
8.31 Hz, 1H, CH), 7.61 (t, J
=
7.51 Hz, 1H, CH), 7.55 (t, J
=
7.61 Hz, 1H, CH), 7.25 (t, J
=
7.21 Hz, 1H, CH), 7.15 (d, J
=
8.39 Hz, 1H, CH); 13CNMR (125 MHz, MeOD) δ = 148 (C-2), 145 (C-6), 140 (C-11), 137 (C-4), 132 (C-14), 129 (C-13), 127 (C-12), 115 (C-5), 112 (C-3); ESI-MS:m/z = 236.31 [M + 2]+, 234.28 [M]+.


## 2.10.
4-Methyl-N-(pyridin-2-yl)benzene Sulfonamide (9b, C12H12N2O2S)

Yield: 935.6 mg (82.1%); m.p.: 178–180°C; TLC:R
f
=
0.72 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3328 (N-H
a
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1665 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1019 (S=O
s
t
r
e
t
c
h
i
n
g), 1161 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1455 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 680 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 224 (15380) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 11.43 (br, s, 1H, NH), 7.97 (d, J
=
8.11 Hz, 1H, CH), 7.61 (d, J
=
8.31 Hz, 1H, CH), 7.25 (t, J
=
7.21 Hz, 1H, CH), 7.20 (s, 1H, CH), 7.11 (t, J
=
8.41 Hz, 1H, CH), 7.15 (d, J
=
8.39 Hz, 1H, CH), 2.48 (s, 3H, CH3); 13CNMR (125 MHz, MeOD) δ = 148 (C-2), 145 (C-6), 143 (C-14), 137 (C-4), 129 (C-13), 115 (C-5), 111 (C-3), 21 (C-17); ESI-MS:m/z = 250.35 [M + 2]+, 248.30 [M]+.


## 2.11. N-(Phenylsulfonyl)-N-(pyridin-2-yl)benzene Sulfonamide (10a, C17H14N2O4S2)

Yield: 909.8 mg (71.7%); m.p.: 166–168°C; TLC:R
f
=
0.62 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3348 (N-H
a
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1619 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1030 (S=O
s
t
r
e
t
c
h
i
n
g), 1186 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1445 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 688 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 215 (12830) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 8.13 (m, 1H, CH), 8.11 (m, 1H, CH), 7.95 (m, 1H, CH), 7.88 (m, 1H, CH), 7.81 (m, 1H, CH), 7.65 (qd, J
=
8.39 Hz, 1.21 Hz, 1H, CH), 7.48 (qd, J
=
7.29 Hz, 5.21 Hz, 1H, CH); 13CNMR (125 MHz, MeOD) δ = 148 (C-6), 142 (C-13), 138 (C-2), 131 (C-16), 130 (C-14), 117 (C-5), 113 (C-3); ESI-MS:m/z = 376.45 [M + 2]+, 374.44 [M]+.


## 2.12.
4-Methyl-N-(phenylsulfonyl)-N-(pyridin-2-yl)benzene Sulfonamide (10b, C19H18N2O4S2)

Yield: 1140.5 mg (84.3%); m.p.: 164–166°C; TLC:R
f
=
0.68 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3348 (N-H
a
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1621 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1027 (S=O
s
t
r
e
t
c
h
i
n
g), 1162 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1445 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 681 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 222 (13855) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 8.19 (s, H, CH), 8.02 (d, J
=
8.09 Hz, 1H, CH), 7.87 (t, J
=
8.41 Hz, 1H, CH), 7.68 (d, J
=
8.11 Hz, 1H, CH), 7.61 (d, J
=
8.37 Hz, 1H, CH), 7.55 (d, J
=
7.27 Hz, 1H, CH), 2.46 (s, 3H, CH3); 13CNMR (125 MHz, MeOD) δ = 148 (C-6), 138 (C-2), 132 (C-15), 117 (C-5), 113 (C-3), 22 (C-27); ESI-MS:m/z = 404.55 [M + 2]+, 402.51 [M]+.


## 2.13.
4-Methyl-N-(phenylsulfonyl)-N-(pyridin-2-yl)benzene Sulfonamide (12a, C18H16N2O4S2)

Yield: 529.5 mg (65.1%); m.p.: 188–190°C; TLC:R
f
=
0.76 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3280 (N-H
a
m
i
n
e
,
s
t
r
e
t
c
h
i
n
g), 1620 (N-H
a
m
i
n
e
,
b
e
n
d
i
n
g), 1021 (S=O
s
t
r
e
t
c
h
i
n
g), 1158 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1445 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 682 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 220 (42550) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 8.15 (d, J
=
7.69 Hz, 1H, CH), 8.07 (d, J
=
8.11 Hz, 1H, CH), 7.98 (d, J
=
7.61 Hz, 1H, CH), 7.91 (t, J
=
8.37 Hz, 1H, CH), 7.65 (d, J
=
8.17 Hz, 1H, CH), 7.51 (d, J
=
7.17 Hz, 1H, CH), 7.45 (d, J
=
7.17 Hz, 1H, CH), 2.44 (s, 3H, CH3); 13CNMR (125 MHz, MeOD) δ = 147 (C-6), 138 (C-2), 132 (C-15), 117 (C-5), 112 (C-3), 21 (C-27); ESI-MS:m/z = 390.53 [M + 2]+, 388.49 [M]+.


## 2.14. N-Methyl-N-(phenylsulfonyl)alanine (15a, C10H13NO4S)

Yield: 786.1 mg (51.7%); m.p.: 132–134°C; TLC:R
f
=
0.72 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3215 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1743 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1444 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1041 (S=O
s
t
r
e
t
c
h
i
n
g), 1183 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1444 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 688 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 215 (13070) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 7.73 (d, J
=
7.69 Hz, 1H, CH), 7.53 (d, J
=
7.51 Hz, 1H, CH), 7.36 (t, J
=
7.61 Hz, 1H, CH), 4.51 (q, J
=
7.17 Hz, 1H, CH), 3.75 (br, s, 1H, OH), 2.71 (s, 3H, CH3), 1.11 (d, J
=
7.17 Hz, 3H, CH3); 13CNMR (125 MHz, MeOD) δ = 178 (C-14), 138 (C-1), 131 (C-4), 62 (C-12), 29 (C-11), 15 (C-13); ESI-MS:m/z = 245.38 [M + 2]+, 243.35 [M]+.


## 2.15. N-Methyl-N-[(4-methylphenyl)sulfonyl]alanine (15b, C11H15NO4S)

Yield: 910.9 mg (63.6%); m.p.: 140–142°C; TLC:R
f
=
0.70 (H2O-BuOH-Acetic acid 1 : 4 : 1); IR (FTIR): υ
- = 3268 (O-H
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1710 (C=O
c
a
r
b
o
x
y
l
i
c
,
s
t
r
e
t
c
h
i
n
g), 1449 (O-H
c
a
r
b
o
x
y
l
i
c
,
b
e
n
d
i
n
g), 1054 (S=O
s
t
r
e
t
c
h
i
n
g), 1146 (-N- S=O
s
t
r
e
t
c
h
i
n
g), 1422 (C=C-C
a
r
o
m
a
t
i
c
,
s
t
r
e
t
c
h
i
n
g), 677 (Ø
-
S
s
t
r
e
t
c
h
i
n
g); UV-Vis (methanol, c
=
2
·
10
-
5 mol dm−3): λ
m
a
x(ε) = 220 (17250) nm (mol−1 dm3cm−1); 1HNMR (500 MHz, MeOD) δ = 7.69 (d, J
=
8.09 Hz, 1H, CH), 7.32 (d, J
=
7.91 Hz, 1H, CH), 4.48 (t, J
=
7.17 Hz, 1H, CH), 3.75 (br, s, 1H, OH), 2.69 (s, 3H, CH3), 2.39 (s, 3H, CH3), 1.08 (d, J
=
7.17 Hz, 3H, CH3); 13CNMR (125 MHz, MeOD) δ = 178 (C-14), 138 (C-1), 133 (C-4), 129 (C-5), 61 (C-12), 29 (C-11), 15 (C-13); ESI-MS:m/z = 259.38 [M + 2]+, 257.35 [M]+.


## 3. Results and Discussion

A total of twelve novel sulfonamides were synthesized in aqueous basic media by simple reaction of creatine (amidine derivatives), amino pyridine (benzene sulfonamide series 1), and methyl alanine (benzene sulfonamide series 2) with benzene sulfonyl chloride and para toluene sulphonyl chloride, respectively, with continuous stirring and details of reaction conditions are explained in Experimental section and synthetic pathways of sulfonamides are explained in Schemes1, 2, 3, and 4. Compounds3a,3b,9a,9b,15a, and15b were synthesized in equimolar concentration of creatine, amino pyridine, and methyl alanine with benzene sulphonyl chloride and para toluene sulphonyl chloride, respectively, while4a,4b,9a, and9b were obtained by bimolar concentration of respective sulphonyl chlorides, respectively. Compounds6a and12a were synthesized by the reaction of3b and9b with benzene sulphonyl chloride and para toluene sulphonyl chloride in equimolar concentration, respectively. All the compounds except compound15a (57.5%) were obtained in good yield. Elemental analysis was performed for the conformation of all the compounds and measurement of absorption maximum (λ
m
a
x) provided the justification. The analytical data of synthesized sulfonamides are presented in Table 1. The synthesized compounds were characterized by FT-IR, and the characteristics band at 1621–1707 cm−1 for imine stretching of amidine sulfonamides, 3280–3367 cm−1 of N-H amide stretching for benzene sulfonamides (series 1), 3250–3268 cm−1 for O-H stretching (benzene sulfonamide series 2), and 1082–1199 cm−1 for (-N-S=O) and 1019–1054 cm−1 (S=O) for all compounds reveals the formation of sulfonamides. [M + 2]+ peaks obtained by ESI-MS represented the isolation of sulfonyl group in all synthesized compounds. The structures of all the compounds were also confirmed by 1HNMR and 13CNMR by dissolving in MeOD. 1HNMR spectra of compounds3a and3b showed a broad signal at δ 9.91, 9.96 while signal at δ 10.76–10.86 for4a,4b, and9a and 11.43, 11.49 ppm for9a and9b corresponds to NH group of sulfonamide. A broad singlet at δ 3.75 ppm due to -OH group was also obtained for compounds15a and15b. The characteristics C-SO-NH signals at δ 155-156 ppm and δ 138–140 ppm for amidine and benzene sulfonamides, respectively, were showed by 13CNMR which identified the structures correctly.Table 1
Physiochemical and analytical data of sulfonamides.
Compounds
Molecular weight
Elemental analysis (found/cal.) %
C
H
N
S
apK
a
3a
271.29
44.33/44.27
4.85/4.83
15.42/15.49
11.83/11.82
10.8
3b
285.32
46.35/46.30
5.39/5.31
14.68/14.73
11.29/11.24
10.8
4a
411.45
46.77/46.71
4.15/4.16
10.26/10.21
15.65/15.59
4.7
4b
439.51
49.17/49.19
4.89/4.82
9.58/9.56
14.57/14.59
4.7
6a
425.48
47.96/47.99
4.54/4.50
7.88/7.98
15.12/15.07
4.7
9a
234.28
56.33/56.39
4.28/4.30
11.88/11.96
13.61/13.69
8.5
9b
248.30
58.03/58.05
4.81/4.87
11.22/11.28
12.85/12.91
8.5
10a
374.44
54.50/54.53
3.68/3.77
7.51/7.48
17.15/17.13
5.3
10b
402.49
56.73/56.70
4.52/4.51
6.88/6.96
15.86/15.93
5.3
12a
388.46
55.63/55.65
4.11/4.15
7.16/7.21
16.46/16.51
5.3
15a
243.28
49.43/49.37
5.41/5.39
5.73/5.76
13.16/13.18
5.0
15b
257.31
51.33/51.35
5.81/5.88
5.36/5.44
12.49/12.46
4.8
apK
a values from ACD, Inc.Synthesized compounds were also screened for their antibacterial against Gram negative bacteriaE. coliand Gram positiveS. aureusandB. subtilis by following the guidelines of CLSI [22, 23] using ciprofloxacin and sulfamethoxazole as reference antibacterial agents. Antifungal activity was also evaluated for synthesized compounds against three strains, namely,A. flavus, A. parasiticus, and A.sp, using itraconazole as reference antifungal agent. Among the bacterial strains, compound3b has excellent antibacterial activities having MIC 40 μg/mL againstS. aureuswith zone of inhibition comparable with control drug (ciprofloxacin). The p
K
a of compound3b is 10.8 which has electron withdrawing inductive effect (mild acidic) for which supports its cell permeability against the particular bacterial strain to bind the proteins. As far as SAR is concerned, amide functional group further supports its activity. Compounds4b and15b showed better activity againstE. coliand compounds3a,4a,4b, and6a have no activity against the Gram positiveS. aureusandB. subtilis while10b,12a,15a, and15b have good activity against these bacterial strains which is higher (MIC 80 μg/mL) than already existing sulfa drug (sulfamethoxazole; MIC 160 μg/mL). The MIC values and zone of inhibitions are presented in Table 2. The activities of above-mentioned compounds are their high permeability into cell due to their acidic behavior by virtue of their lower p
K
a values (4.7–5.3), while the p
K
a value of sulfamethoxazole is 5.7. The electrostatic interaction of methyl group with protein and pyridine further supports their antibacterial activities [24].Table 2
Zonea of inhibition and MICb of sulfonamides against pathogenic bacterial strains.
Compounds
Name of bacteria
Gram (+) bacterial strains
Gram (−) bacterial strains
S. aureus
B. subtilis
E. coli
(ATCC 25923)
(ATCC 6633)
(ATCC 25922)
Zone of inhibition
MIC
Zone of inhibition
MIC
Zone of inhibition
MIC
3a
—, —, —
—
—, —, —
—
9, —, —
>160
3b
32, 29, 26
40
8, —, —
>160
—, —, —
—
4a
—, —, —
—
—, —, —
—
—, —, —
—
4b
—, —, —
—
—, —, —
—
28, 25, 22
80
6a
—, —, —
—
—, —, —
—
9, —, —
>160
9a
—, —, —
—
9, —, —
160
9, —, —
>160
9b
—, —, —
—
8, —, —
>160
—, —, —
—
10a
9, —, —
>160
—, —, —
—
14, 10, —
160
10b
27, 24, 22
80
—, —, —
—
—, —, —
—
12a
9, —, —
>160
28, 24, 21
80
—, —, —
—
15a
29, 26, 21
80
—, —, —
—
—, —, —
—
15b
—, —, —
—
27, 24, 22
80
28, 25, 20
80
Ciprofloxacinc
36, 34, 31
0.5
36, 33, 31
0.5
35, 34, 31
0.5
Sulfamethoxazoled
—, —, —
—
16, 13, —
160
33, 28, 25
40
aZone of inhibition was measured in mm at concentration of 160, 80, and 40 μg mL−1.
bMIC (minimum inhibitory concentrations) were measured in μg mL−1.
cControl drug; dsulfa drug.Among the fungal strains, compounds9a and9b have excellent activity againstA. parasiticusandA. flavus, respectively, while10a and15a showed better activity againstA. parasiticus andA.sp. was insensitive to all strains except compound15b (MIC 160 μg/mL). The amide bond formations in the above-mentioned synthesized compounds have excellent activities against the fungal strains as far as the SAR is concerned [25–27]. It is concluded that newly synthesized sulfonamides exhibited greater activity than reference itraconazole. The MIC values and zone of inhibitions are reported in Table 3.Table 3
Zonea of inhibition and MICb of sulfonamides against pathogenic fungal strains.
Compounds
Name of fungi
A. parasiticus
A. flavus
A.sp.
(ATCC 15517)
(ATCC 9643)
(ATCC 200667)
Zone of inhibition
MIC
Zone of inhibition
MIC
Zone of inhibition
MIC
3a
—, —, —
—
—, —, —
—
—, —, —
—
3b
—, —, —
—
12, —, —
160
—, —, —
—
4a
9, —, —
>160
—, —, —
—
—, —, —
—
4b
—, —, —
—
—, —, —
—
—, —, —
—
6a
—, —, —
—
—, —, —
—
—, —, —
—
9a
24, 21, 18
40
—, —, —
—
—, —, —
—
9b
22, 19, 13
80
22, 19, 15
40
9, —, —
>160
10a
21, 18, 12
80
—, —, —
—
—, —, —
—
10b
—, —, —
—
24, 20, 18
80
13, —, —
160
12a
—, —, —
—
12, —, —
160
—, —, —
—
15a
24, 21, 18
80
—, —, —
—
—, —, —
—
15b
11, —, —
>160
—, —, —
—
15, 12, —
160
Itraconazolec
18, 11, —
160
21, 19, 15
80
12, —, —
>160
aZone of inhibition was measured in mm at concentration of 160, 80, and 40 μg mL−1.
bMIC (minimum inhibitory concentrations) were measured in μg mL−1.
cControl drug.


## 4. Conclusion

Amidine and benzene sulfonamides derivatives were synthesized and evaluated biologically. Among the synthesized compounds3b was proved potent antibacterial agent with MIC 40 μg/mL and zone of inhibition comparable with ciprofloxacin and more effective than sulfamethoxazole. Synthetic compounds9a and9b showed better inhibition than itraconazole againstA. parasiticusandA. flavus, respectively, with MIC 40 μg/mL.



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*Source: 524056-2015-09-28.xml*