Crystal structure and Hirshfeld-surface analysis of a monoclinic polymorph of 2-amino-5-chloro­benzo­phenone oxime at 90 K

Geetha, D.; Kavitha, C.N.; Divakara, T.R.; Basavaraju, Y.B.; Yathirajan, H.S.; Parkin, S.

doi:10.1107/S2056989023004668

research communications

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 79| Part 7| July 2023| Pages 610-613

https://doi.org/10.1107/S2056989023004668

Open

access

Crystal structure and Hirshfeld-surface analysis of a monoclinic polymorph of 2-amino-5-chlorobenzophenone oxime at 90 K

Doreswamy Geetha,^a Channappa N. Kavitha,^b Thayamma R. Divakara,^c Yeriyur B. Basavaraju,^a Hemmige S. Yathirajan ^a ^* and Sean Parkin ^d

^aDepartment of Studies in Chemistry, University of Mysore, Manasagangotri, Mysuru-570 006, India, ^bDepartment of Chemistry, Government Science College, Hassan-573 201, India, ^cT. John Institute of Technology, Bengaluru-560 083, India, and ^dDepartment of Chemistry, University of Kentucky, Lexington, KY, 40506-0055, USA
^*Correspondence e-mail: yathirajan@hotmail.com

Edited by B. Therrien, University of Neuchâtel, Switzerland (Received 19 May 2023; accepted 26 May 2023; online 6 June 2023)

The synthesis and crystal structure of a monoclinic polymorph of 2-amino-5-chlorobenzophenone oxime, C₁₃H₁₁ClN₂O, are presented. The molecular conformation results from twisting of the phenyl and 2-amino-5-chloro benzene rings attached to the oxime group, which subtend a dihedral angle of 80.53 (4)°. In the crystal, centrosymmetric dimers are formed as a result of pairs of strong O—H⋯N hydrogen bonds. A comparison is made to a previously known triclinic polymorph, including differences in atom–atom contacts obtained via a Hirshfeld-surface analysis.

Keywords: crystal structure; benzophenone oxime; polymorph; Hirshfeld surface.

CCDC reference: 2265648

1. Chemical context

2-Amino-5-chlorobenzophenone is an ecologically friendly cross-linking agent. Benzophenone and related compounds have been reported to act as anti-allergic, anti-inflammatory, anti-asthmatic, and anti-anaphylactic agents (Evans et al., 1987 ; Wiesner et al., 2002 ; Sieron et al., 2004 ). Benzophenone derivatives are widely used in sunscreen lotions, offering UV-A and UV-B protection (Deleu et al., 1992 ). 2-Amino-5-chlorobenzophenone is used to produce intermediates for the synthesis of oxazolam drugs and intermediates for psychotherapeutic agents, such as chlorodiazepoxide and diazepam (Sternbach & Reeder, 1961a ,b ). 2-Aminobenzophenone and its derivatives have importance because of their applications in heterocyclic synthesis and medicines (Walsh, 1980 ) and are also used as anti-mitotic agents (Liou et al., 2002 ). The growth and characterization of 2-amino-5-chlorobenzophenone single crystals was reported by Mohamed et al. (2007 ). Synthesis, herbicidal evaluation and structure–activity relationships of some benzophenone oxime ether derivatives was reported by Ma et al. (2015 ). The synthesis, physicochemical, and biological evaluation of 2-amino-5-chlorobenzophenone derivatives as potent skeletal muscle relaxants was reported by Singh et al. (2015 ). Details of synthetic methodologies and the pharmacological significance of 2-aminobenzophenones as versatile building blocks was published by Chaudhary et al. (2018 ). The reactivity of oximes for diverse methodologies and synthetic applications was recently reported by Rykaczewski et al. (2022 ). In view of the general importance of benzophenone derivatives and those of 2-amino-5-chlorobenzophenone in particular, this paper reports the 90 K crystal structure and Hirshfeld-surface studies of a monoclinic form of 2-amino-5-chlorobenzophenone oxime, C₁₃H₁₁ClN₂O, mon-2A-5CBO. A triclinic polymorph was recently published as a CSD communication (refcode REZSIB) by Lanzilotto, Housecroft et al. (2018 ). Some comparisons between the two crystal structures are presented.

2. Structural commentary

The overall conformation of the mon-2A-5CBO molecule (Fig. 1) is determined by torsion angles about the C6—C7 and C7—C8 bonds that connect the chloroaniline and phenyl rings to the oxime carbon, C7. These are held in check by an intra-molecular hydrogen bond, N1—H1NA⋯O1 [d_D⋯A = 2.8875 (19) Å, Table 1]. These torsion angles result in a dihedral angle between the two rings of 80.53 (4)°. The conformation defining torsion and dihedral angles are gathered in Table 2 along with those of the triclinic polymorph, REZSIB (Lanzilotto, Housecroft et al., 2018). The conformations of the 2A-5CBO molecules in the two polymorphs are quite similar, as shown by the overlay plot in Fig. 2. The r.m.s. deviation obtained from a weighted least-squares fit of all non-hydrogen atoms using OFIT in SHELXTL-XP (Sheldrick, 2008 ) is only 0.1315 Å, with the largest deviation being 0.267 Å for C12.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1NA⋯O1	0.91 (2)	2.23 (2)	2.8875 (19)	128.7 (16)
O1—H1O⋯N2ⁱ	0.95 (2)	1.84 (2)	2.7411 (16)	156.4 (19)
Symmetry code: (i) .

Table 2
Comparison of conformation-defining torsion and dihedral angles (°) in mon-2A-5CBO and CSD entry REZSIB

	mon-2A-5CBO	REZSIB^a,b
Torsion angle
N1—C1—C6—C7	−1.3 (2)	−5.6
C1—C6—C7—N2	60.8 (2)	56.7
C6—C7—N2—O1	0.5 (2)	7.8
Dihedral angle
C1–C6/C8–C13	80.53 (4)	75.82
Notes: (a) The numbering scheme in REZSIB is different from mon-2A-5CBO; (b) Values from Mercury (Macrae et al., 2020 ), therefore there are no SUs.

Figure 1
An ellipsoid plot (50% probability) of mon-2A-5CBO. The intramolecular N—H⋯O hydrogen bond is shown as a dashed line.

Figure 2
A least-squares fit overlay of mon-2A-5CBO and the triclinic polymorph REZSIB (red).

3. Supramolecular features

The main supramolecular constructs in the mon-2A-5CBO crystal structure are R₂²(6) centrosymmetric dimers that result from pairs (O1—H1O⋯N2^inv and O1^inv—H1O^inv⋯N2, inv = 1 − x, 1 − y, 1 − z) of strong hydrogen bonds [d_D⋯A = 2.7411 (16) Å, Table 1]. These are shown as dashed lines in Fig. 3 along with a representation of the Hirshfeld surface, as generated by CrystalExplorer (Spackman et al., 2021 ), on which the hydrogen bonds are responsible for the prominent red spots. Similar dimer motifs are present in REZSIB. The most striking difference in packing between the two polymorphs is that REZSIB exhibits slip-stacked π–π overlap [interplanar separation = 3.340 (2) Å, centroid–centroid distance = 3.897 (2) Å] of inversion-related (1 − x, −y, 1 − z) chloroaniline rings, whereas mon-2A-5CBO does not. Hirshfeld surface 2D-fingerprint plots for mon-2A-5CBO are shown in Fig. 4 and the differences in contacts between the polymorphs are summarized in Table 3.

Table 3
Atom–atom contact coverages (%) for polymorphs mon-2A-5CBO and REZSIB

Atom contacts^a	mon-2A-5CBO	REZSIB
H⋯H	38.6	43.6
H⋯C	27.1	17.6
H⋯Cl	15.8	13.6
H⋯N	7.8	8.8
H⋯O	5.1	6.4
C⋯Cl	4.4	6.0
C⋯C	0.0	3.9
Note: (a) Includes reciprocal contacts. All other contact percentages are negligible.

Figure 3
A partial packing plot of mon-2A-5CBO viewed approximately down the b-axis showing the Hirshfeld surface (left) and the R₂²(6) centrosymmetric dimer formed by pairs of O—H⋯N hydrogen bonds (dashed lines and prominent red spots).

Figure 4
Hirshfeld surface two-dimensional fingerprint plots of mon-2A-5CBO showing (a) H⋯H, (b) H⋯C, (c) H⋯Cl, (d) H⋯N, (e) H⋯O, and (f) C⋯Cl close contacts.

4. Database survey

A survey of the Cambridge Structural Database (CSD: v5.43 including all updates through November 2022; Groom et al., 2016 ) returned 5507 hits for a search fragment consisting of unsubstituted benzophenone. A search using benzophenone oxime as the probe, however, returned only 35 entries. Of these, ten have a nitrogen-bound functional group at the ortho-position of one of the benzene rings, while six have `any halogen' attached at one of the meta-positions. In only two structures is this halogen a chlorine atom: YIFCIC (Lanzilotto, Prescimone et al., 2018 ), C₁₅H₁₁Cl₂FN₂O₂, systematic name 2-chloro-N-{4-chloro-2-[(2-fluorophenyl)(hydroxyimino)methyl]phenyl}acetamide and REZSIB (Lanzilotto, Housecroft et al., 2018), the triclinic (P $[\overline{1}]$ ) polymorph of the monoclinic (P2₁/n) 2A-5CBO crystal structure described herein.

Some other related crystal structures include 2-amino-5-chlorobenzophenone as monoclinic (NUVFAL; Vasco-Mendez et al., 1996 ) and triclinic (NUVFAL02; Javed et al., 2018 ) polymorphs, benzophenone oxime (XULKUK; Sharutin et al., 2002 ), and 2-benzoyloxy-5-methylbenzophenone (OCAMOV; Sieron et al., 2004).

5. Synthesis and crystallization

The synthesis of 2A-5CBO (Fig. 5) was by a modification of Beckmann's conversion of benzophenone to benzophenone oxime (Beckmann, 1886 ). In a 100 ml round-bottom flask fitted with a magnetic stirrer was placed a mixture of 100 mmol (23.2 g) of 2-amino-5-chlorobenzophenone, 120 mmol (7 g) of hydroxylamine hydrochloride in 10 ml of ethanol. To this stirred mixture, 0.5 g of sodium hydroxide pellets was added in small portions. When the reaction became vigorous, the flask was placed in an ice bath. A condenser was attached to the flask and the mixture was refluxed for 5 minutes on a steam bath. The solution was cooled and poured into a beaker containing 5 ml of hydrochloric acid and crushed ice. This was stirred until a precipitate formed. After filtering the precipitate with suction and washing with cold distilled water, the product was spread out on filter paper and air dried. The yield was 87%. X-ray quality crystals were obtained from methanol by slow evaporation (m.p.: 390–393 K).

Figure 5
A general reaction scheme for the formation of 2A-5CBO.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 4. All hydrogen atoms were found in difference-Fourier maps. Those bound to carbon were subsequently included in the refinement using a riding model, with constrained distances fixed at 0.95 Å and U_iso(H) values set to 1.2U_eq of the attached atom. The amine and oxime hydrogen atoms were refined freely.

Table 4
Experimental details

Crystal data
Chemical formula	C₁₃H₁₁ClN₂O
M_r	246.69
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	90
a, b, c (Å)	12.8264 (3), 5.5423 (1), 17.4082 (4)
β (°)	109.522 (1)
V (Å³)	1166.37 (4)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.31
Crystal size (mm)	0.30 × 0.24 × 0.02

Data collection
Diffractometer	Bruker D8 Venture dual source
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.924, 0.971
No. of measured, independent and observed [I > 2σ(I)] reflections	26003, 2680, 2294
R_int	0.042
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.033, 0.083, 1.05
No. of reflections	2680
No. of parameters	166
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.32, −0.27
Computer programs: APEX3 (Bruker, 2016 ), SHELXT (Sheldrick, 2015a ), SHELXL2019/2 (Sheldrick, 2015b ), XP in SHELXTL (Sheldrick, 2008), SHELX (Sheldrick, 2008) and publCIF (Westrip, 2010 )'.

Supporting information

CCDC reference: 2265648

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S2056989023004668/tx2069sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989023004668/tx2069Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2056989023004668/tx2069Isup3.cml

checkCIF report

Computing details top

Data collection: APEX3 (Bruker, 2016); cell refinement: APEX3 (Bruker, 2016); data reduction: APEX3 (Bruker, 2016); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2019/2 (Sheldrick, 2015b); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELX (Sheldrick, 2008) and publCIF (Westrip, 2010)'.

4-Chloro-2-[(hydroxyimino)(phenyl)methyl]aniline top

Crystal data top

C₁₃H₁₁ClN₂O	F(000) = 512
M_r = 246.69	D_x = 1.405 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
a = 12.8264 (3) Å	Cell parameters from 9975 reflections
b = 5.5423 (1) Å	θ = 2.5–27.5°
c = 17.4082 (4) Å	µ = 0.31 mm⁻¹
β = 109.522 (1)°	T = 90 K
V = 1166.37 (4) Å³	Semi-regular block, pale yellow
Z = 4	0.30 × 0.24 × 0.02 mm

Data collection top

Bruker D8 Venture dual source diffractometer	2680 independent reflections
Radiation source: microsource	2294 reflections with I > 2σ(I)
Detector resolution: 7.41 pixels mm^-1	R_int = 0.042
φ and ω scans	θ_max = 27.5°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −16→16
T_min = 0.924, T_max = 0.971	k = −7→7
26003 measured reflections	l = −22→22

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.033	Hydrogen site location: mixed
wR(F²) = 0.083	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ²(F_o²) + (0.0334P)² + 0.6832P] where P = (F_o² + 2F_c²)/3
2680 reflections	(Δ/σ)_max = 0.001
166 parameters	Δρ_max = 0.32 e Å⁻³
0 restraints	Δρ_min = −0.27 e Å⁻³

Special details top

Experimental. The crystal was mounted using polyisobutene oil on the tip of a fine glass fibre, which was fastened in a copper mounting pin with electrical solder. It was placed directly into the cold gas stream of a liquid-nitrogen based cryostat (Hope, 1994; Parkin & Hope, 1998).

Diffraction data were collected with the crystal at 90K, which is standard practice in this laboratory for the majority of flash-cooled crystals.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Cl1	0.63274 (3)	0.54249 (7)	0.94134 (2)	0.03072 (12)
O1	0.58250 (8)	0.6496 (2)	0.57328 (6)	0.0249 (2)
H1O	0.5830 (17)	0.572 (4)	0.5245 (14)	0.055 (6)*
N1	0.58120 (12)	1.1196 (3)	0.64451 (9)	0.0292 (3)
H1NA	0.5690 (15)	1.042 (4)	0.5962 (12)	0.037 (5)*
H1NB	0.6301 (17)	1.238 (4)	0.6523 (12)	0.045 (6)*
N2	0.47023 (9)	0.6201 (2)	0.56650 (7)	0.0198 (3)
C1	0.59550 (11)	0.9785 (3)	0.71326 (9)	0.0203 (3)
C2	0.66473 (11)	1.0555 (3)	0.79012 (9)	0.0235 (3)
H2	0.705557	1.200830	0.794290	0.028*
C3	0.67496 (11)	0.9256 (3)	0.85971 (9)	0.0223 (3)
H3	0.720922	0.983038	0.911337	0.027*
C4	0.61783 (11)	0.7109 (3)	0.85389 (8)	0.0197 (3)
C5	0.54751 (10)	0.6311 (3)	0.77926 (8)	0.0172 (3)
H5	0.507391	0.485190	0.776017	0.021*
C6	0.53533 (10)	0.7638 (3)	0.70891 (8)	0.0165 (3)
C7	0.45154 (10)	0.6753 (2)	0.63216 (8)	0.0165 (3)
C8	0.33591 (10)	0.6438 (2)	0.63101 (7)	0.0156 (3)
C9	0.29101 (11)	0.8182 (3)	0.66846 (8)	0.0189 (3)
H9	0.335250	0.950014	0.695888	0.023*
C10	0.18202 (11)	0.8003 (3)	0.66587 (9)	0.0226 (3)
H10	0.151395	0.920969	0.690712	0.027*
C11	0.11782 (11)	0.6062 (3)	0.62701 (9)	0.0229 (3)
H11	0.043042	0.594435	0.624967	0.028*
C12	0.16249 (12)	0.4292 (3)	0.59117 (9)	0.0226 (3)
H12	0.118668	0.294962	0.565375	0.027*
C13	0.27141 (11)	0.4477 (3)	0.59285 (8)	0.0189 (3)
H13	0.301768	0.326585	0.567964	0.023*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0381 (2)	0.0335 (2)	0.01636 (17)	−0.00308 (17)	0.00354 (14)	0.00155 (15)
O1	0.0139 (5)	0.0399 (7)	0.0236 (5)	−0.0007 (4)	0.0097 (4)	−0.0040 (5)
N1	0.0323 (7)	0.0244 (7)	0.0325 (7)	−0.0064 (6)	0.0128 (6)	0.0057 (6)
N2	0.0127 (5)	0.0282 (7)	0.0205 (6)	0.0008 (5)	0.0081 (4)	0.0002 (5)
C1	0.0172 (6)	0.0191 (7)	0.0269 (7)	0.0009 (5)	0.0105 (5)	0.0007 (6)
C2	0.0178 (6)	0.0199 (7)	0.0342 (8)	−0.0042 (6)	0.0107 (6)	−0.0058 (6)
C3	0.0149 (6)	0.0262 (8)	0.0247 (7)	−0.0012 (5)	0.0051 (5)	−0.0081 (6)
C4	0.0177 (6)	0.0235 (7)	0.0176 (6)	0.0017 (5)	0.0057 (5)	−0.0005 (5)
C5	0.0142 (6)	0.0178 (7)	0.0200 (6)	−0.0010 (5)	0.0063 (5)	−0.0023 (5)
C6	0.0132 (6)	0.0182 (7)	0.0192 (6)	0.0009 (5)	0.0069 (5)	−0.0019 (5)
C7	0.0158 (6)	0.0167 (7)	0.0172 (6)	0.0018 (5)	0.0060 (5)	0.0020 (5)
C8	0.0153 (6)	0.0188 (7)	0.0135 (6)	0.0016 (5)	0.0057 (5)	0.0029 (5)
C9	0.0194 (6)	0.0191 (7)	0.0191 (6)	−0.0007 (5)	0.0077 (5)	−0.0010 (5)
C10	0.0209 (7)	0.0246 (8)	0.0260 (7)	0.0029 (6)	0.0128 (6)	−0.0001 (6)
C11	0.0158 (6)	0.0295 (8)	0.0248 (7)	−0.0003 (6)	0.0086 (5)	0.0053 (6)
C12	0.0211 (7)	0.0240 (8)	0.0216 (7)	−0.0059 (6)	0.0055 (5)	0.0002 (6)
C13	0.0207 (6)	0.0197 (7)	0.0171 (6)	0.0003 (5)	0.0073 (5)	0.0001 (5)

Geometric parameters (Å, º) top

Cl1—C4	1.7409 (14)	C5—H5	0.9500
O1—N2	1.4145 (14)	C6—C7	1.4903 (18)
O1—H1O	0.95 (2)	C7—C8	1.4869 (17)
N1—C1	1.3894 (19)	C8—C13	1.3927 (19)
N1—H1NA	0.91 (2)	C8—C9	1.3937 (19)
N1—H1NB	0.89 (2)	C9—C10	1.3871 (18)
N2—C7	1.2809 (17)	C9—H9	0.9500
C1—C2	1.402 (2)	C10—C11	1.386 (2)
C1—C6	1.4065 (19)	C10—H10	0.9500
C2—C3	1.377 (2)	C11—C12	1.385 (2)
C2—H2	0.9500	C11—H11	0.9500
C3—C4	1.383 (2)	C12—C13	1.3913 (19)
C3—H3	0.9500	C12—H12	0.9500
C4—C5	1.3834 (18)	C13—H13	0.9500
C5—C6	1.3920 (19)

N2—O1—H1O	100.5 (13)	C1—C6—C7	123.03 (12)
C1—N1—H1NA	117.7 (13)	N2—C7—C8	116.31 (12)
C1—N1—H1NB	113.8 (13)	N2—C7—C6	125.78 (12)
H1NA—N1—H1NB	112.5 (17)	C8—C7—C6	117.90 (11)
C7—N2—O1	112.76 (11)	C13—C8—C9	119.48 (12)
N1—C1—C2	120.65 (14)	C13—C8—C7	121.94 (12)
N1—C1—C6	121.17 (13)	C9—C8—C7	118.58 (12)
C2—C1—C6	118.03 (13)	C10—C9—C8	120.30 (13)
C3—C2—C1	121.59 (13)	C10—C9—H9	119.9
C3—C2—H2	119.2	C8—C9—H9	119.9
C1—C2—H2	119.2	C11—C10—C9	119.97 (13)
C2—C3—C4	119.53 (13)	C11—C10—H10	120.0
C2—C3—H3	120.2	C9—C10—H10	120.0
C4—C3—H3	120.2	C12—C11—C10	120.11 (13)
C3—C4—C5	120.47 (13)	C12—C11—H11	119.9
C3—C4—Cl1	119.77 (11)	C10—C11—H11	119.9
C5—C4—Cl1	119.76 (11)	C11—C12—C13	120.14 (13)
C4—C5—C6	120.23 (13)	C11—C12—H12	119.9
C4—C5—H5	119.9	C13—C12—H12	119.9
C6—C5—H5	119.9	C12—C13—C8	119.98 (13)
C5—C6—C1	120.10 (12)	C12—C13—H13	120.0
C5—C6—C7	116.75 (12)	C8—C13—H13	120.0

N1—C1—C2—C3	176.07 (13)	C1—C6—C7—N2	60.8 (2)
C6—C1—C2—C3	0.5 (2)	C5—C6—C7—C8	55.87 (17)
C1—C2—C3—C4	1.5 (2)	C1—C6—C7—C8	−120.15 (14)
C2—C3—C4—C5	−2.5 (2)	N2—C7—C8—C13	39.36 (18)
C2—C3—C4—Cl1	178.60 (11)	C6—C7—C8—C13	−139.76 (13)
C3—C4—C5—C6	1.4 (2)	N2—C7—C8—C9	−139.76 (13)
Cl1—C4—C5—C6	−179.73 (10)	C6—C7—C8—C9	41.12 (17)
C4—C5—C6—C1	0.7 (2)	C13—C8—C9—C10	−1.7 (2)
C4—C5—C6—C7	−175.41 (12)	C7—C8—C9—C10	177.41 (12)
N1—C1—C6—C5	−177.17 (13)	C8—C9—C10—C11	1.0 (2)
C2—C1—C6—C5	−1.63 (19)	C9—C10—C11—C12	0.4 (2)
N1—C1—C6—C7	−1.3 (2)	C10—C11—C12—C13	−1.1 (2)
C2—C1—C6—C7	174.25 (12)	C11—C12—C13—C8	0.3 (2)
O1—N2—C7—C8	−178.54 (11)	C9—C8—C13—C12	1.05 (19)
O1—N2—C7—C6	0.5 (2)	C7—C8—C13—C12	−178.07 (12)
C5—C6—C7—N2	−123.16 (15)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1NA···O1	0.91 (2)	2.23 (2)	2.8875 (19)	128.7 (16)
O1—H1O···N2ⁱ	0.95 (2)	1.84 (2)	2.7411 (16)	156.4 (19)

Symmetry code: (i) −x+1, −y+1, −z+1.

Comparison of conformation-defining torsion and dihedral angles (°) in mon-2A-5CBO and CSD entry REZSIB top

	mon-2A-5CBO	REZSIB^a^,^b
Torsion angle
N1—C1—C6—C7	-1.3 (2)	-5.6
C1—C6—C7—N2	60.8 (2)	56.7
C6—C7—N2—O1	0.5 (2)	7.8
Dihedral angle
C1–C6/C8–C13	80.53 (4)	75.82

Notes: (a) The numbering scheme in REZSIB is different from mon-2A-5CBO; (b) Values from Mercury (Macrae et al., 2020), therefore there are no SUs.

Atom–atom contact coverages (%) for polymorphs mon-2A-5CBO and REZSIB top

Atom contacts^a	mon-2A-5CBO	REZSIB
H···H	38.6	43.6
H···C	27.1	17.6
H···Cl	15.8	13.6
H···N	7.8	8.8
H···O	5.1	6.4
C···Cl	4.4	6.0
C···C	0.0	3.9

Note: (a) Includes reciprocal contacts. All other contact percentages are negligible.

Acknowledgements

DG is grateful to DOS in Chemistry, University of Mysore for providing research facilities. HSY thanks UGC for a BSR Faculty fellowship for three years.

Funding information

Funding for this research was provided by: National Science Foundation, Directorate for Mathematical and Physical Sciences (award No. CHE-1625732 to SP).

References

Beckmann, E. (1886). Ber. Dtsch. Chem. Ges. 19, 988–993. CrossRef Google Scholar
Bruker (2016). APEX3. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Chaudhary, S., Sharda, S., Prasad, D. N., Kumar, S. & Singh, R. K. (2018). Asia. J. Org. Med. Chem. 3, 107–115. CrossRef Google Scholar
Deleu, H., Maes, M. & Roelandts, R. (1992). Photodermatol. Photoimmunol. Photomed. 9, 29–32. PubMed CAS Web of Science Google Scholar
Evans, D., Cracknell, M. E., Saunders, J. C., Smith, C. E., Williamson, W. R. N., Dawson, W. & Sweatman, W. J. F. (1987). J. Med. Chem. 30, 1321–1327. CrossRef CAS PubMed Web of Science Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CrossRef IUCr Journals Google Scholar
Gulam Mohamed, M., Rajarajan, K., Mani, G., Vimalan, M., Prabha, K., Madhavan, J. & Sagayaraj, P. (2007). J. Cryst. Growth, 300, 409–414. Web of Science CrossRef Google Scholar
Javed, S., Faizi, M. S. H., Nazia, S. & Iskenderov, T. (2018). IUCrData, 3, x181444. Google Scholar
Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3–10. Web of Science CSD CrossRef ICSD CAS IUCr Journals Google Scholar
Lanzilotto, A., Housecroft, C. E., Constable, E. C. & Prescimone, A. (2018). CSD Communication (refcode REZSIB). CCDC, Cambridge, England. Google Scholar
Lanzilotto, A., Prescimone, A., Constable, E. C. & Housecroft, C. E. (2018). CSD Communication (refcode YIFCIC). CCDC, Cambridge, England. Google Scholar
Liou, J. P., Chang, C. W., Song, J. S., Yang, Y. N., Yeh, C. F., Tseng, H. Y., Lo, Y. K., Chang, Y. L., Chang, C. M. & Hsieh, H. P. (2002). J. Med. Chem. 45, 2556–2562. Web of Science CrossRef PubMed CAS Google Scholar
Ma, J., Ma, M., Sun, L., Zeng, Z. & Jiang, H. (2015). J. Chem. 2015 Article ID 435219. Google Scholar
Macrae, C. F., Sovago, I., Cottrell, S. J., Galek, P. T. A., McCabe, P., Pidcock, E., Platings, M., Shields, G. P., Stevens, J. S., Towler, M. & Wood, P. A. (2020). J. Appl. Cryst. 53, 226–235. Web of Science CrossRef CAS IUCr Journals Google Scholar
Rykaczewski, K. A., Wearing, E. R., Blackmun, D. E. & Schindler, C. S. (2022). Nat. Synth. 1, 24–36. CrossRef Google Scholar
Sharutin, V. V., Sharutina, O. K., Molokova, O. V., Ettenko, E. N., Krivolapov, D. B., Gubaidullin, A. T. & Litvinov, I. A. (2002). Zh. Obshch. Khim. 72, 893–898. CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sieroń, L., Shashikanth, S., Yathirajan, H. S., Venu, T. D., Nagaraj, B., Nagaraja, P. & Khanum, S. A. (2004). Acta Cryst. E60, o1889–o1891. Web of Science CSD CrossRef IUCr Journals Google Scholar
Singh, R. K., Devi, S. & Prasad, D. N. (2015). Arab. J. Chem. 8, 307–312. Web of Science CrossRef CAS Google Scholar
Spackman, P. R., Turner, M. J., McKinnon, J. J., Wolff, S. K., Grimwood, D. J., Jayatilaka, D. & Spackman, M. A. (2021). J. Appl. Cryst. 54, 1006–1011. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sternbach, L. H. & Reeder, E. (1961a). J. Org. Chem. 26, 1111–1118. CrossRef CAS Web of Science Google Scholar
Sternbach, L. H. & Reeder, E. (1961b). J. Org. Chem. 26, 4936–4941. CrossRef CAS Web of Science Google Scholar
Vasco-Mendez, N. L., Panneerselvam, K., Rudino-Pinera, E. & Soriano-Garcia, M. (1996). Anal. Sci. 12, 677–678. CAS Google Scholar
Walsh, D. A. (1980). Synthesis, pp. 677–688. CrossRef Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wiesner, J., Kettler, K., Jomaa, H. & Schlitzer, M. (2002). Bioorg. Med. Chem. Lett. 12, 543–545. Web of Science CrossRef PubMed CAS Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.