N-(5-Bromo­pyridin-2-yl)acetamide

Hoong-Kun Fun; Tara Shahani; Rajesha Kumar; Arun M Isloor; Kammasandra N Shivananda

doi:10.1107/S1600536811027553

. 2011 Jul 16;67(Pt 8):o2043. doi: 10.1107/S1600536811027553

N-(5-Bromopyridin-2-yl)acetamide

Hoong-Kun Fun ^a,^*,^‡, Tara Shahani ^a, Rajesha Kumar ^b, Arun M Isloor ^b, Kammasandra N Shivananda ^c

PMCID: PMC3213491 PMID: 22091070

Abstract

The asymmetric unit of the title compound, C₇H₇BrN₂O, contains two molecules, in one of which the methyl H atoms are disorderd over two orientations in a 0.57 (3):0.43 (3) ratio. The dihedral angles between the pyridine rings and the acetamide groups are 7.27 (11) and 8.46 (11)°. In the crystal, molecules are linked by N—H⋯O and C—H⋯O hydrogen bonds generating bifurcated R ₂ ¹(5) ring motifs, which in turn lead to [110] chains.

Related literature

For background to the acetylation of amines, see: Greene & Wuts (1999 ▶); Moore et al. (1940 ▶); Suyama & Gerwick (2006 ▶). For a related structure, see: Loureiro et al. (2008 ▶). For further synthetic information, see: Augustine et al. (2011 ▶); Sollogoub et al. (2002 ▶).

Experimental

Crystal data

C₇H₇BrN₂O
M _r = 215.06
Triclinic,
a = 4.0014 (3) Å
b = 8.7232 (6) Å
c = 23.0626 (18) Å
α = 82.127 (1)°
β = 86.897 (1)°
γ = 85.932 (1)°
V = 794.60 (10) Å³
Z = 4
Mo Kα radiation
μ = 5.11 mm⁻¹
T = 296 K
0.77 × 0.15 × 0.09 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009) ▶ T _min = 0.111, T _max = 0.665
13194 measured reflections
5134 independent reflections
3193 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.031
wR(F ²) = 0.081
S = 1.00
5134 reflections
201 parameters
H-atom parameters constrained
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.25 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811027553/hb5933sup1.cif

e-67-o2043-sup1.cif^{(19.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811027553/hb5933Isup2.hkl

e-67-o2043-Isup2.hkl^{(251.4KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811027553/hb5933Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2A—H1NA⋯O1Bⁱ	0.85	2.16	3.001 (2)	169
N2B—H1NB⋯O1Aⁱⁱ	0.83	2.20	2.985 (2)	159
C7A—H7AA⋯O1Bⁱ	1.10	2.54	3.476 (3)	142

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

Acknowledgments

HKF and TSH thank Universiti Sains Malaysia (USM) for the Research University Grant (1001/PFIZIK/811160). TSH also thanks USM for the award of a research fellowship. AMI thanks Professor Sandeep Sanchethi, Director, National Institute of Technology–Karnataka, India, for his encouragement, and also the Defence Research and Development Organization, Government of India, for financial support.

supplementary crystallographic information

Comment

The acetylation of amines is an important method for protection (Greene & Wuts, 1999) of this basic functionality that is an important part of many natural products and medicinally important compounds such as sulphanilamide (Moore et al., 1940). In addition, certain natural products and medicinal compounds contain the acetamide functionality as part of the native compound or drug. Examples include epiquinamide, a compound isolated from a poison frog (Suyama et al., 2006) and Tylenol a common analgesic compound. Prompted by these, we synthesized the title compound, (I), and determined its crystal structure.

The asymmetric unit of (I) consists of two independent molecules of N-(5-bromopyridin-2-yl)acetamide (A & B) as shown in Fig. 1. In molecule A, the methyl hydrogen atoms are disordered over two sets of sites, with occupancy ratio of 0.57 (3):0.43 (3). The pyridine (N1A/C1A–C5A)/(N1B/C1B–C5B) rings are essentially planar, with maximum deviations of 0.006 (2) Å for atom C4A and 0.004 (2) Å for atom N1B, respectively. The dihedral angle between the pyridine (N1A/C1A–C5A)/(N1B/C1B–C5B) rings and acetamide (N2A/O1A/C5A–C7A)/ (N2B/O1B/C5B–C7B) groups are 7.27 (11)° and 8.46 (11)° respectively. The bond lengths and angles are normal and comparable to those in a related structure (Loureiro et al., 2008).

In the crystal (Fig. 2), the molecules are linked by intermolecular N2A—H1NA···O1B, N2B—H1NB···O1A and C7A—H7AA···O1B hydrogen bonds (Table 1) generating a bifurcated R¹₂(5) ring motif, resulting in supramolecular [1 1 0] chains.

Experimental

(1E)-1-(5-Bromopyridin-2-yl)-N-hydroxyethanimine (2 g, 0.0093 mol) was taken in N,N dimethyl formamide (20 ml) at 25–26°C under a nitrogen atmosphere. Propylphosphonic anhydride (0.6 g, 0.00093 mol, 50% solution in ethylacetate) was added at the same temperature (Augustine et al., 2011). The reaction mixture was heated to 100°C for 5 hrs. The reaction mixture was cooled to 25–26°C and quenched onto ice-cold water. The precipitated white solid was filtered and dried under vacuum to get the desired product as a white solid which was then recrystallized from ethanol (Sollogoub et al., 2002) to yield colourless needles of (I). Yield 1.89 g (94.5%) Mp. 447–449 K.