2-[N-(2,3-Dimethylphenyl)-carbamoyl]benzenesulfonamide and the 3,4- and 2,6-dimethylphenyl analogues

Article abstract of DOI:10.1107/S0108270108016314

The structures of 2-[(2,3-dimethyl-phen-yl)carbamo-yl]benzene-sulfonamide, 2-[(3,4-dimethyl-phen-yl)carbamo-yl]benzene-sulfon-amide and 2-[(2,6-dimethyl-phen-yl)carbamo-yl]benzene-sulfon-amide, all C15H16N2O3S, are stabilized by extensive intra- and inter

Full text of DOI:10.1107/S0108270108016314

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
and 2,6- for (III)]. The three dimethylphenyl-substituted
analogues are closely related to the fenamate class of
nonsteroidal anti-inflammatory drugs and are expected to
exhibit very potent biological activities since sulfonamide and
carbamoyl functions exist in the same nucleus simultaneously.
ISSN 0108-2701
2-[N-(2,3-Dimethylphenyl)carbam-
oyl]benzenesulfonamide and the 3,4-
and 2,6-dimethylphenyl analogues
Waseeq Ahmad Siddiqui,a Saeed Ahmad,b Hamid Latif
Siddiquic and Masood Parvezd*
aDepartment of Chemistry, University of Sargodha, Pakistan, bDepartment of
Chemistry, University of Science and Technology, Bannu, Pakistan, cInstitute of
Chemistry, University of the Punjab, Lahore, Pakistan, and dDepartment of
Chemistry, The University of Calgary, 2500 University Drive NW, Calgary, Alberta,
Canada T2N 1N4
The molecular structure of (I) is presented in Fig. 1. The
mean planes of the benzene rings (C1–C6 and C8–C13) are
inclined at 8.19 (8)ꢀ with respect to one another, while the
carbamoyl group (O3/N2/C7) is inclined at 55.43 (13) and
48.73 (13)ꢀ, respectively, to these rings. Atoms S1 and C7 lie
Correspondence e-mail: parvez@ucalgary.ca
Received 6 May 2008
Accepted 29 May 2008
Online 7 June 2008
˚
0.062 (3) and 0.066 (4) A from the mean plane of the C1–C6
ring, on opposite sides, indicating a significant strain on this
portion of the molecule. The structure contains two distinct
patterns of hydrogen bonds, involving intermolecular N—
Hꢁ ꢁ ꢁO interactions (Fig. 2). The sulfonamide groups are
hydrogen bonded via atoms N1 and O1, forming dimers about
inversion centers at (0, 21, 0) and (0, 0, 12 ) along the b and c axes.
The eight-membered rings thus formed may be described in
graph-set notation as R22(8) (Bernstein et al., 1994). The
carbamoyl groups are also involved in hydrogen bonds,
involving atoms O3 and N2, resulting in chains of molecules
running parallel to the c axis and affording stability to the
structure. In addition, there is a rather weak nonclassical
intermolecular hydrogen bond (C4—H4ꢁ ꢁ ꢁO1iii; details of the
hydrogen-bonding geometry are provided in Table 1). The
structure is further stabilized by three additional intra-
molecular interactions, viz. N1—H1Nꢁ ꢁ ꢁO3, C2—H2ꢁ ꢁ ꢁO1
and C14—H14Dꢁ ꢁ ꢁN2, resulting in seven-, five- and five-
membered rings representing S(7), S(5) and S(5) motifs,
respectively (Bernstein et al., 1994).
The structures of 2-[(2,3-dimethylphenyl)carbamoyl]benzene-
sulfonamide, 2-[(3,4-dimethylphenyl)carbamoyl]benzenesulfon-
amide and 2-[(2,6-dimethylphenyl)carbamoyl]benzenesulfon-
amide, all C15H16N2O3S, are stabilized by extensive intra- and
intermolecular hydrogen bonds. In all three structures, the
sulfonamide and carbamoyl groups are involved in hydrogen
bonding. In the 2,3-dimethyl and 2,6-dimethyl derivatives,
dimeric units and chains of molecules are formed parallel to
the c axis. In the 3,4-dimethyl derivative, the hydrogen
bonding creates tetrameric units, resulting in macrocyclic
R44(22) rings that form sheets in the ab plane. The three
analogues are closely related to the fenamate class of
nonsteroidal anti-inflammatory drugs.
Comment
Saccharin derivatives have always been of interest because of
their diverse applications (Marta et al., 2003; Culf et al., 1997).
Their open-ring benzenesulfonamide derivatives have shown
cyclooxygenase-2 (COX-2) inhibitory action and act as
analgesic and anti-inflammatory agents (Eatedal et al., 2002).
Various biologically important saccharin skeletons and their
N-alkyl derivatives have been efficiently prepared (Xu et al.,
2006) by chromium oxide-catalyzed oxidation of N-alkyl-2-
methylarenesulfonamides in acetonitrile as well as by the
already developed methodology utilizing irradiation from
tungsten and mercury lamps (Masashi et al., 1999) for a similar
type of conversion. In continuation of our research on 1,2-
benzothiazine 1,1-dioxide and saccharin derivatives (Siddiqui,
Ahmad, Khan & Siddiqui, 2007; Siddiqui, Ahmad, Khan et al.,
2008; Siddiqui, Ahmad, Siddiqui et al., 2007; Siddiqui, Ahmad,
Tariq et al., 2008), we now report the syntheses and crystal
structures of the title compounds, 2-[(X-dimethylphenyl)-
carbamoyl]benzenesulfonamide [X = 2,3- for (I), 3,4- for (II)
The molecular structure of (II) is presented in Fig. 3. The
mean planes of the benzene rings (C1–C6 and C8–C13) are
Figure 1
An ORTEP-3 (Farrugia, 1997) drawing of (I), with displacement
ellipsoids plotted at the 50% probability level.
Acta Cryst. (2008). C64, o367–o371
doi:10.1107/S0108270108016314
# 2008 International Union of Crystallography o367

organic compounds
inclined at 40.55 (8)ꢀ with respect to one another, while the
carbamoyl group (O1/N2/C7) is inclined at 59.30 (13) and
26.05 (18)ꢀ, respectively, to these rings. A comparison of
mean-plane angles shows that the conformations of (I) and
(II) are significantly different from one another. Molecules of
(II) related by translational symmetry along the a and b axes
form a cluster of four molecules via N1—H1Nꢁ ꢁ ꢁO1i and N2—
H3Nꢁ ꢁ ꢁO3ii hydrogen bonds (details of the hydrogen-bonding
geometry are provided in Table 2), resulting in a macrocyclic
ring (Fig. 4) that may be described in graph-set notation as
R44(22) (Bernstein et al., 1994). These hydrogen bonds result in
the formation of sheets that are extended in the ab plane. The
structure is further stabilized by three additional intra-
molecular interactions, viz. N1—H2Nꢁ ꢁ ꢁO3, C13—H13ꢁ ꢁ ꢁO3
and C2—H2ꢁ ꢁ ꢁO1, resulting in seven-, six- and five-membered
rings representing S(7), S(6) and S(5) motifs, respectively
(Bernstein et al., 1994) (Fig. 3 and Table 2).
Figure 4
Intermolecular interactions (dashed lines) in the unit cell of (II), showing
macrocyclic rings formed by clusters of four molecules; these clusters are
further extended into sheets in the ab plane.
Figure 5
An ORTEP-3 (Farrugia, 1997) drawing of molecule A of (III), with
displacement ellipsoids plotted at the 50% probability level.
Figure 2
Intermolecular interactions (dashed lines) in the unit cell of (I), showing
eight-membered rings formed by sulfonamide groups and chains formed
by carbamoyl groups running parallel to the c axis.
Figure 3
An ORTEP-3 (Farrugia, 1997) drawing of (II), with displacement
ellipsoids plotted at the 50% probability level.
Figure 6
An ORTEP-3 (Farrugia, 1997) drawing of molecule B of (III), with
displacement ellipsoids plotted at the 50% probability level.
ꢂ
o368 Siddiqui et al. Three forms of C15H16N2O3S
Acta Cryst. (2008). C64, o367–o371

organic compounds
The asymmtric unit of (III) is composed of two independent
molecules (hereafter called A and B), depicted in Figs. 5 and 6,
respectively. In molecule A, the mean planes of the benzene
rings (C1a–C6a and C8a–C13a) are inclined at 6.53 (9)ꢀ with
respect to one another, while the carbamoyl group (O3a/N2a/
C7a) is inclined at 60.34 (16) and 57.20 (17)ꢀ, respectively, to
these rings. The corresponding mean-plane angles in molecule
B are 3.11 (10), 61.17 (16) and 59.10 (17)ꢀ, respectively. The
conformations of both molecules of (III) are more closely
related to the conformation of (I). The sulfonamide groups of
the two molecules in (III) are hydrogen bonded to form
dimeric units; the eight-membered rings thus formed repre-
sent R22(8) motifs (Bernstein et al., 1994). The carbamoyl
groups of molecules A and B are hydrogen bonded to form
chains of molecules running parallel to the a axis (Fig. 7). The
two molecules contain an identical pair of intramolecular
interactions, viz. N1a/b—Hꢁ ꢁ ꢁO3a/b and C2a/b—H2a/bꢁ ꢁ ꢁ
O1a/b, resulting in seven- and five-membered rings repre-
senting S(7) and S(5) motifs, respectively (Bernstein et al.,
1994). However, the intramolecular interactions involving
hydrogen bonding to atom C15 show markedly different
patterns in the two molecules; in molecule A, atom C15 is
bonded to O3a, while in molecule B, it is bonded to N2b,
resulting in S(7) and S(5) motifs, respectively.
similar structures (Clark et al., 2003; Vyas et al., 2003; Singh et
al., 2004; Bocelli et al., 1995; Sutton & Cody, 1989; Furuya et
al., 1989; Siddiqui, Ahmad, Khan et al., 2008; Siddiqui, Ahmad,
Tariq et al., 2008), with S O, S—N, S—C, N2—C7, N2—C8
and C O distances lying in very close ranges of 1.430 (2)–
1.438 (2), 1.598 (3)–1.614 (3), 1.773 (3)–1.781 (3), 1.331 (4)–
˚
1.338 (4), 1.429 (4)–1.440 (4) and 1.236 (3)–1.241 (3) A,
respectively. The C—N—C angle at N2 in (II) is significantly
larger than the corresponding angles in (I), (IIIA) and (IIIB).
The remaining angles lie within narrow ranges in all three
structures.
In all molecules, the conformation about the S—N bond is
in agreement with the conformation of a handful of structures
containing an o-C-substituted benzenesulfonamide fragment
[Cambridge Structural Database (CSD), Version 5.29; Allen,
2002]. The N1 atoms in all these structures are tetrahedral, the
sum of angles around this atom being in the range 334–340ꢀ.
The H atoms bonded to atom N1, and atoms O1 and O2
bonded to S1, are staggered, as observed in chlorophenyl
analogues of the title compounds (Siddiqui, Ahmad, Khan et
al., 2008) and the compound with CSD refcode COYVER
(Foresti et al., 1985). Several structures have been reported
wherein the H and O atoms of the sulfonamide unit are
eclipsed, e.g. CSD refcodes ENIROI (Vyas et al., 2003),
GUFQED01 (Clark et al., 2003) and ZZZULS01 (Tremayne et
al., 2002). Classical work on the three-dimensional orientation
of sulfonamides has been reported by several groups of
investigators (e.g. Bordner et al., 1984, 1989; Beddoes et al.,
1986; Street et al., 1987; Luger et al., 1996; Helliwell et al., 1997;
Bhatt et al., 2005).
The molecular dimensions in all three structures are in
agreement with the corresponding dimensions reported for
Experimental
Suspensions of saccharin (1.0 g, 5.46 mmol) and dimethylaniline (5 ml
in the case of 2,3- and 2,6-dimethylaniline, and 0.5 g in the case of 3,4-
dimethylaniline) in xylene (25 ml) were stirred at room temperature
for 1.5 h and then heated at 373 K for 2–7 h. The reaction mixtures
were subsequently cooled to room temperature, filtered and dried to
obtain colorless solid products. The products were crystallized from
MeOH/CH3CN (1:3) solutions by slow evaporation at 313 K.
For (I): m.p. 463–465 K. IR (neat, ꢀmax, cmꢃ1): NH2 3415, 3325; CO
1650; SO2 1343, 1150; 1H NMR (300 MHz, methanol-d4): ꢁ 2.30 (s, 3H,
CH3), 2.35 (s, 3H, CH3), 7.12–7.34 (m, 3H, C6H3), 7.63–8.10 (m, 4H,
C6H4); 13C NMR: ꢁ 169.7, 142.2, 138.8, 137.3, 135.4, 134.3, 132.2, 131.7,
130.5, 129.5, 124.2, 120.5, 21.4, 20.8. LRMS (ES+): m/z: 304.09 [M+]
(39.7%).
For (II): m.p. 443–444 K. IR (neat, ꢀmax, cmꢃ1): NH2 3425, 3365;
CO 1705; SO2 1354, 1167; 1H NMR (300 MHz, methanol-d4): ꢁ 2.30 (s,
3H, CH3), 2.35 (s, 3H, CH3), 7.12–7.32 (m, 2H, C6H3), 7.53–7.70 (m,
4H, C6H4), 8. 20 (m, 1H, C6H3); 13C NMR: ꢁ 171.8, 144.2, 140.9, 139.2,
137.4, 136.3, 134.2, 133.7, 132.5, 131.6, 126.3, 122.5, 23.5, 22.9. LRMS
(ES+): m/z: 304.09 [M+] (25.1%).
For (III): m.p. 496–497 K. IR (neat, ꢀmax, cmꢃ1): NH2 3423, 3345;
CO 1715; SO2 1345, 1150; 1H NMR (300 MHz, methanol-d4): ꢁ 2.30 (s,
3H, CH3), 2.42 (s, 3H, CH3), 7.26–7.52 (m, 3H, C6H3), 7.68–8.10 (m,
4H, C6H4); 13C NMR: ꢁ 168.7, 141.2, 139.7, 139.2, 137.4, 136.3, 134.2,
133.7, 132.5, 130.4, 125.3, 121.1, 22.3, 21.1. LRMS (ES+): m/z: 304.09
[M+] (21.9%).
Figure 7
Intermolecular interactions (dashed lines) in the unit cell of (III),
showing eight-membered rings formed by sulfonamide groups and chains
formed by carbamoyl groups running parallel to the a axis.
ꢂ
Acta Cryst. (2008). C64, o367–o371
Siddiqui et al.
Three forms of C15H16N2O3S o369

organic compounds
Table 3
Hydrogen-bond geometry (A, ) for (III).
Compound (I)
ꢀ
˚
Crystal data
D—Hꢁ ꢁ ꢁA
D—H
Hꢁ ꢁ ꢁA
Dꢁ ꢁ ꢁA
D—Hꢁ ꢁ ꢁA
3
˚
V = 1473.2 (14) A
Z = 4
Mo Kꢃ radiation
ꢄ = 0.23 mmꢃ1
T = 173 (2) K
C15H16N2O3S
Mr = 304.36
Monoclinic, P21=c
N1a—H1Naꢁ ꢁ ꢁO2bi
N2a—H3Naꢁ ꢁ ꢁO3bii
N1b—H1Nbꢁ ꢁ ꢁO1aiii
N1b—H2Nbꢁ ꢁ ꢁO1bii
N2b—H3Nbꢁ ꢁ ꢁO3aiv
N1a—H2Naꢁ ꢁ ꢁO3a
N1b—H1Nbꢁ ꢁ ꢁO3b
0.91 (3)
0.90 (3)
0.81 (3)
0.95 (3)
0.90 (3)
0.91 (3)
0.81 (3)
2.17 (3)
2.08 (3)
2.58 (3)
2.04 (3)
2.03 (3)
2.04 (3)
2.33 (4)
2.891 (4)
2.971 (3)
2.996 (3)
2.941 (4)
2.921 (4)
2.863 (4)
2.993 (4)
135 (3)
174 (3)
114 (3)
157 (3)
170 (3)
151 (3)
139 (3)
˚
a = 12.842 (7) A
˚
b = 15.153 (9) A
˚
c = 7.572 (4) A
0.40 ꢄ 0.04 ꢄ 0.02 mm
ꢂ = 91.16 (4)ꢀ
Data collection
Symmetry codes: (i) ꢃx þ 2; ꢃy; ꢃz þ 1; (ii) ꢃx þ 1; ꢃy þ 1; ꢃz þ 1; (iii) ꢃx þ 1; ꢃy,
ꢃz þ 1; (iv) ꢃx þ 2; ꢃy þ 1; ꢃz þ 1.
Nonius KappaCCD diffractometer
Absorption correction: multi-scan
(SORTAV; Blessing, 1997)
9490 measured reflections
2583 independent reflections
1926 reflections with I > 2ꢅ(I)
Rint = 0.059
Compound (III)
Tmin = 0.913, Tmax = 0.995
Crystal data
Refinement
C15H16N2O3S
Mr = 304.36
Triclinic, P1
a = 7.968 (3) A
˚
b = 8.509 (5) A
c = 21.510 (11) A
ꢃ = 84.30 (2)ꢀ
ꢂ = 82.46 (3)ꢀ
ꢇ = 88.66 (3)ꢀ
V = 1438.5 (12) A
Z = 4
Mo Kꢃ radiation
ꢄ = 0.24 mmꢃ1
T = 173 (2) K
0.12 ꢄ 0.07 ꢄ 0.06 mm
R[F2 > 2ꢅ(F2)] = 0.043
wR(F2) = 0.114
S = 1.09
2583 reflections
200 parameters
H atoms treated by a mixture of
independent and constrained
refinement
3
˚
˚
ꢃ3
˚
Áꢆmax = 0.26 e A
ꢃ3
˚
Áꢆmin = ꢃ0.52 e A
˚
Table 1
Hydrogen-bond geometry (A, ) for (I).
ꢀ
˚
Data collection
D—Hꢁ ꢁ ꢁA
D—H
Hꢁ ꢁ ꢁA
Dꢁ ꢁ ꢁA
D—Hꢁ ꢁ ꢁA
Nonius KappaCCD diffractometer
Absorption correction: multi-scan
(SORTAV; Blessing, 1997)
9182 measured reflections
5044 independent reflections
3197 reflections with I > 2ꢅ(I)
Rint = 0.062
N2—H3Nꢁ ꢁ ꢁO3i
N1—H2Nꢁ ꢁ ꢁO1ii
N1—H1Nꢁ ꢁ ꢁO3
C4—H4ꢁ ꢁ ꢁO1iii
0.87 (3)
0.84 (3)
0.92 (3)
0.95
2.08 (3)
2.13 (3)
2.04 (3)
2.53
2.941 (3)
2.963 (3)
2.850 (3)
3.268 (3)
170 (2)
171 (3)
146 (2)
134
Tmin = 0.972, Tmax = 0.986
Refinement
1
2
1
2
1
2
Symmetry codes: (i) x; ꢃy þ ; z þ ; (ii) ꢃx þ 2; ꢃy þ 1; ꢃz; (iii) ꢃx þ 2; y ꢃ ,
R[F2 > 2ꢅ(F2)] = 0.050
wR(F2) = 0.134
S = 1.02
5044 reflections
401 parameters
H atoms treated by a mixture of
independent and constrained
refinement
1
ꢃz þ .
2
ꢃ3
˚
Áꢆmax = 0.27 e A
Compound (II)
ꢃ3
˚
Áꢆmin = ꢃ0.39 e A
Crystal data
3
˚
V = 1399.0 (17) A
Z = 4
For the three title structures, H atoms bonded to C atoms were
included in the refinements at geometrically idealized positions with
C15H16N2O3S
Mr = 304.36
Monoclinic, P21=c
Mo Kꢃ radiation
ꢄ = 0.24 mmꢃ1
T = 173 (2) K
0.20 ꢄ 0.10 ꢄ 0.06 mm
˚
aromatic and methyl C—H distances of 0.95 and 0.98 A, respectively,
˚
a = 11.597 (9) A
and Uiso(H) values of 1.2 times Ueq of the atoms to which they were
bonded; the H atoms bonded to atom C14 in (I) were equally
disordered over six sites. H atoms bonded to N atoms were allowed to
refine with Uiso(H) values of 1.2 times Ueq of the N atoms. The final
difference maps were free of chemically significant features.
For all three compounds, data collection: COLLECT (Hooft,
1998); cell refinement: DENZO (Otwinowski & Minor, 1997); data
reduction: SCALEPACK (Otwinowski & Minor, 1997); program(s)
used to solve structure: SAPI91 (Fan, 1991); program(s) used to
refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics:
ORTEP-3 (Farrugia, 1997); software used to prepare material for
publication: SHELXL97.
˚
b = 7.450 (3) A
˚
c = 16.324 (13) A
ꢂ = 97.29 (3)ꢀ
Data collection
Nonius KappaCCD diffractometer
Absorption correction: multi-scan
(SORTAV; Blessing, 1997)
4440 measured reflections
2423 independent reflections
1767 reflections with I > 2ꢅ(I)
Rint = 0.048
Tmin = 0.953, Tmax = 0.986
Refinement
R[F2 > 2ꢅ(F2)] = 0.055
wR(F2) = 0.154
S = 1.05
2423 reflections
201 parameters
H atoms treated by a mixture of
independent and constrained
refinement
ꢃ3
˚
Áꢆmax = 0.31 e A
Áꢆmin = ꢃ0.41 e A
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: HJ3076). Services for accessing these data are
described at the back of the journal.
ꢃ3
˚
Table 2
Hydrogen-bond geometry (A, ) for (II).
ꢀ
˚
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