2-Chloro-N-(4-hy­droxy­phen­yl)acetamide

Abderrazzak El Moutaouakil Ala Allah; Benson M Kariuki; Issam Ameziane El Hassani; Abdulsalam Alsubari; Walid Guerrab; Musa A Said; Youssef Ramli

doi:10.1107/S2414314624010150

. 2024 Oct 24;9(Pt 10):x241015. doi: 10.1107/S2414314624010150

2-Chloro-N-(4-hydroxyphenyl)acetamide

Abderrazzak El Moutaouakil Ala Allah ^a, Benson M Kariuki ^b, Issam Ameziane El Hassani ^a, Abdulsalam Alsubari ^c,^*, Walid Guerrab ^a, Musa A Said ^d, Youssef Ramli ^a,^*

PMCID: PMC11660168 PMID: 39712662

The title compound is significantly distorted from planarity, with a twist angle between the planes through the hydroxybenzene and acetamide groups being 23.5 (2)°. This conformation is supported by intramolecular C—H⋯O and N—H⋯Cl contacts. In the crystal, N—H⋯O hydrogen-bonding contacts between acetamide groups and O—H⋯O contacts between hydroxyl groups form tapes propagating parallel to [103].

Keywords: crystal structure, acetamide, hydrogen-bonding

Abstract

The title compound, C₈H₈ClNO₂, is significantly distorted from planarity, with a twist angle between the planes through the hydroxybenzene and acetamide groups being 23.5 (2)°. This conformation is supported by intramolecular C—H⋯O and N—H⋯Cl contacts. In the crystal, N—H⋯O hydrogen-bonding contacts between acetamide groups and O—H⋯O contacts between hydroxyl groups form tapes propagating parallel to [103].

Structure description

N-arylacetamides are intermediates for the synthesis of medicinal, agrochemical and pharmaceutical compounds (Missioui et al., 2021 ▸). As part of our ongoing studies of these systems (Missioui et al., 2022 ▸), we now describe the synthesis and structure of the title compound, C₈H₈ClNO₂.

The molecule, Fig. 1 ▸, is almost planar as indicated by a twist angle between the planes through the hydroxybenzene (C1–C6, O1) and acetamide (C7, C8, N1, O2) groups being 23.5 (2)°; the acetamide group has an anti conformation. The chloro substituent deviates only slightly from the plane of the acetamide group as indicated by the N1—C7—C8—Cl1 torsion angle of 15.4 (4)°.

The molecule of 2-chloro-N-(4-hydroxyphenyl)acetamide showing the atom-numbering scheme and displacement parameters at the 50% probability level. The intramolecular C—H⋯O and N—H⋯Cl contacts are shown as green dotted lines.

Two types of close intramolecular contacts occur within the molecule. The first contact is of the type C—H⋯O with a C3—H3⋯O2 angle of 116° and a C3⋯O2 distance of 2.873 (4) Å, Table 1 ▸. Similar contacts are observed in related structures including 2-chloro-N-(4-fluorophenyl)acetamide (Kang et al., 2008 ▸), 2-chloro-N-phenylacetamide (Gowda et al., 2008 ▸) and 2-chloro-N-(4-chlorophenyl)acetamide (Gowda et al., 2007 ▸). The second contact is of the type N—H⋯Cl and has a N1—H1⋯Cl1 angle of 115° and a N1⋯Cl1 distance of 2.999 (2) Å.

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯O2	0.93	2.34	2.873 (4)	116
N1—H1⋯Cl1	0.86	2.53	2.999 (2)	115
N1—H1⋯O2ⁱ	0.86	2.28	3.025 (3)	145
O1—H1A⋯O1ⁱⁱ	0.82	2.06	2.8585 (17)	166

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Symmetry codes: (i) Inline graphic ; (ii) .

In the crystal, neighbouring molecules are linked by N—H⋯O hydrogen-bonding between translationally related acetamide groups with a N1—H1⋯O2ⁱ [symmetry code: (i) x, y − 1, z] angle of 145° and a N1⋯O2ⁱ distance of 3.025 (3) Å, Table 1 ▸, to form linear chains parallel to the b axis (Fig. 2 ▸). The molecules are also bridged by O—H⋯O contacts with a O1—H1A⋯O1ⁱⁱ [symmetry code: (ii) −x + 2, y + Inline graphic , −z + 2] angle of 166° and an O1⋯O1ⁱⁱ distance of 2.8585 (17) Å which, by themselves assemble molecules along the 2₁ screw axis in the b-axis direction. The combined hydrogen-bonding interactions result in almost flat tapes of molecules parallel to [03].

A segment of the packing in the crystal of 2-chloro-N-(4-hydroxyphenyl)acetamide showing the intermolecular N—H⋯O and O—H⋯O hydrogen bonds as green dotted lines.

Synthesis and crystallization

4-Aminophenol (1 mmol) was dissolved in pure acetic acid (30 ml) and placed in an ice-bath. Subsequently, chloroacetyl chloride (1.2 mmol) was added portion-wise under stirring. At the end of the reaction, a solution of sodium acetate (25 ml) was added, and a solid precipitate formed after 30 min of stirring at room temperature. The resulting solid was filtered, washed with cold water, dried and recrystallized from its ethanol solution to yield the title compound as colourless crystals.

Yield = 89%, colour:colourless, m.p. = 413–415 K. FT–IR (ATR, ν, cm⁻¹): 3385 (OH), 3200 (NH), 1640 (C=O). ¹H NMR (500 MHz, DMSO-d₆): δ p.p.m. 4.21 (s, 2H, CH₂), 6.76–7.34 (m, 4H, Ar—H), 9.20 (s, 1H, OH), 10.23 (s, 1H, NH). ¹³C NMR (500 MHz, DMSO-d₆): 43.42 (CH₂); 117.68, 122.20, 131.50, 132.63, 153.68 (C—Ar); 164.76 (C=O). HRMS (ESI): calculated for C₈H₈ClNO₂ [M - H]⁺ 186.0224, found 186.0328.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸.

Table 2. Experimental details.

Crystal data
Chemical formula	C₈H₈ClNO₂
M _r	185.60
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	296
a, b, c (Å)	6.5088 (6), 5.1758 (5), 12.2175 (14)
β (°)	101.649 (10)
V (Å³)	403.11 (7)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.43
Crystal size (mm)	0.45 × 0.20 × 0.07

Data collection
Diffractometer	SuperNova, Dual, Cu at home/near, Atlas
Absorption correction	Gaussian (CrysAlis PRO; Rigaku OD, 2023 ▸)
T_min, T_max	0.642, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	3642, 1902, 1487
R _int	0.028
(sin θ/λ)_max (Å⁻¹)	0.697

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.081, 1.06
No. of reflections	1902
No. of parameters	110
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.16, −0.19
Absolute structure	Flack x determined using 510 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 ▸)
Absolute structure parameter	0.11 (5)

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Computer programs: CrysAlis PRO (Rigaku OD, 2023 ▸), SHELXT (Sheldrick, 2015a ▸), SHELXL2019/2 (Sheldrick, 2015b ▸), Mercury (Macrae et al., 2020 ▸) and WinGX (Farrugia, 2012 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2414314624010150/tk4111sup1.cif

x-09-x241015-sup1.cif^{(136.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2414314624010150/tk4111Isup2.hkl

x-09-x241015-Isup2.hkl^{(152.8KB, hkl)}

x-09-x241015-Isup3.cml^{(3.2KB, cml)}

Supporting information file. DOI: 10.1107/S2414314624010150/tk4111Isup3.cml

CCDC reference: 2392239

Additional supporting information: crystallographic information; 3D view; checkCIF report

Acknowledgments

YR is thankful to the National Center for Scientific and Technical Research of Morocco (CNRST) for its continuous support. The contributions of the authors are as follows: conceptualization, YR; methodology, AA; investigation, AEMAA and IAEH; writing (original draft), AEMAA; writing (review and editing of the manuscript), YR; formal analysis, YR and BMK; supervision, YR; crystal structure determination, BMK.

full crystallographic data