8-Bromo­naphthalen-1-amine

Amy L Fuller; Fergus R Knight; Alexandra M Z Slawin; J Derek Woollins

doi:10.1107/S1600536808012580

. 2008 May 3;64(Pt 6):o977. doi: 10.1107/S1600536808012580

8-Bromonaphthalen-1-amine

Amy L Fuller ^a, Fergus R Knight ^a, Alexandra M Z Slawin ^a,^*, J Derek Woollins ^a

PMCID: PMC2961535 PMID: 21202706

Abstract

The title compound, C₁₀H₈BrN, was obtained by slow addition of sodium azide to 8-bromo-1-naphthoic acid, followed by addition of aqueous ammonia. The crude product was crystallized from petroleum ether to give pink crystals. Compared to other 1,8-disubstituted naphthalene compounds, this compound exhibits less strain between the 1 and 8 substituents. Additionally, the NH protons form both intra- and intermolecular hydrogen bonds. The naphthalene units are arranged in a herring-bone stacking motif.

Related literature

For examples of sterically crowded 1,8 dichalcogen naphthalenes, see: Aucott et al. (2004 ▶). For the synthesis, see: Herbert et al. (1987 ▶).

Experimental

Crystal data

C₁₀H₈BrN
M _r = 222.08
Monoclinic,
a = 13.6692 (14) Å
b = 4.1579 (4) Å
c = 15.8256 (16) Å
β = 109.941 (3)°
V = 845.52 (15) Å³
Z = 4
Mo Kα radiation
μ = 4.81 mm⁻¹
T = 125.1 K
0.35 × 0.13 × 0.09 mm

Data collection

Rigaku SCXmini diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.381, T _max = 0.649
6823 measured reflections
1527 independent reflections
1281 reflections with F ² > 2σ(F ²)
R _int = 0.061

Refinement

R[F ² > 2σ(F ²)] = 0.051
wR(F ²) = 0.116
S = 1.10
1527 reflections
110 parameters
H-atom parameters constrained
Δρ_max = 1.76 e Å⁻³
Δρ_min = −0.39 e Å⁻³

Data collection: SCXmini (Rigaku/MSC, 2006 ▶); cell refinement: PROCESS-AUTO (Rigaku, 1998 ▶); data reduction: PROCESS-AUTO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: CrystalStructure (Rigaku/MSC, 2006 ▶); software used to prepare material for publication: CrystalStructure.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808012580/si2087sup1.cif

e-64-0o977-sup1.cif^{(14.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808012580/si2087Isup2.hkl

e-64-0o977-Isup2.hkl^{(75.3KB, hkl)}

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
N1—H1a⋯Br1	0.98	2.27	3.070 (3)	138
N1—H1b⋯N1ⁱ	0.98	2.20	3.073 (5)	148

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Symmetry code: (i) Inline graphic .

supplementary crystallographic information

Comment

Contrary to the formally bonded (and sterically strained) S—S or Te—Te atoms in positions 1 and 8 in previous naphthalene compounds (Aucott et al., 2004), the title compound C₁₀H₈BrN exhibits a somewhat unstrained, intramolecular non-bonded Br1···N1 distance of 3.070 (3) Å. The molecular structure of the title compound is shown in Figure 1. An intramolecular hydrogen bonding interaction between the N1—H1a···Br1 enables a close nonbonding Br1···N1 distance and at the same time leaves the molecule relatively unstrained.

The other NH proton is involved in the intermolecular hydrogen bond (Table 1) N1—H1b···N1 and forms an infinite zigzag chain. These chains have normal hydrophobic contact to each other (Figure 2). The naphthalene units are arranged in a herringbone stacking motif.

Experimental

The title compound was prepared by a method previously described (Herbert et al., 1987). Sodium azide (3.10 g, 0.048 mol) was added over a 10 minute period to a stirred suspension of 8-bromo-1-naphthoic acid (2.0 g, 0.008 mol) in concentrated sulfuric acid (7 ml) and chloroform (7 ml) at 45° C. Each successive portion of sodium azide being added after the effervescence resulting from the previous addition had subsided. The mixture was stirred for 90 minutes at 45°C and added to water (140 ml), and it was made alkaline with aqueous ammonia and extracted with chloroform (3 x 140 ml). The combined extracts were dried with magnesium sulfate and evaporated to give the desired product. Yield 1.30 g (73%). The black crude product was recrystallized from 60–80 petroleum ether to give pink crystals.