N-(4-Chloro­phen­yl)ethanimidamide

Nubia Boechat; Warner B Kover; Sabrina B Ferreira; Solange M S V Wardell; James L Wardell; Edward R T Tiekink

doi:10.1107/S1600536810011013

. 2010 Mar 27;66(Pt 4):o958. doi: 10.1107/S1600536810011013

N-(4-Chlorophenyl)ethanimidamide

Nubia Boechat ^a, Warner B Kover ^b, Sabrina B Ferreira ^a, Solange M S V Wardell ^c, James L Wardell ^d,^‡, Edward R T Tiekink ^e,^*

PMCID: PMC2984039 PMID: 21580761

Abstract

A twisted conformation is found in the title compound, C₈H₉ClN₂, with the ethanimidamide residue being twisted substantially to the benzene ring [dihedral angle = 66.54 (14)°]. The conformation about the C=N double bond [1.299 (3) Å] is Z. A two-dimensional array with a zigzag topology is formed in the crystal structure via N—H⋯N and N—H⋯Cl hydrogen-bonding interactions.

Related literature

For background to the synthesis of N-(p-chlorophenyl)acetamidine and related N-arylacetamidines used as reagents in the formation of anti-leishmanial compounds, see: Shearer et al. (1997 ▶); Rousselet et al. (1993 ▶); Patai (1975 ▶). For background to leismaniasis, see: Ouellette et al. (2004 ▶); Croft et al. (2006 ▶); Ferreira et al. (2007 ▶); World Health Organization (2010 ▶).

Experimental

Crystal data

C₈H₉ClN₂
M _r = 168.62
Orthorhombic,
a = 9.6460 (9) Å
b = 9.0192 (4) Å
c = 19.3281 (5) Å
V = 1681.53 (18) Å³
Z = 8
Mo Kα radiation
μ = 0.39 mm⁻¹
T = 120 K
0.35 × 0.20 × 0.10 mm

Data collection

Nonius KappaCCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2007 ▶) T _min = 0.792, T _max = 1.000
14006 measured reflections
1924 independent reflections
1185 reflections with I > 2σ(I)
R _int = 0.081

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.150
S = 1.05
1924 reflections
107 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.33 e Å⁻³

Data collection: COLLECT (Hooft, 1998 ▶); cell refinement: DENZO (Otwinowski & Minor, 1997 ▶) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and DIAMOND (Brandenburg, 2006 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810011013/hg2664sup1.cif

e-66-0o958-sup1.cif^{(14.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810011013/hg2664Isup2.hkl

e-66-0o958-Isup2.hkl^{(92.9KB, 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
N2—H1n⋯N1ⁱ	0.88 (3)	2.08 (3)	2.965 (3)	176 (3)
N2—H2n⋯Cl1ⁱⁱ	0.80 (3)	2.83 (3)	3.464 (2)	138 (3)

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

Acknowledgments

The use of the EPSRC X-ray crystallographic service at the University of Southampton, England, and the valuable assistance of the staff there is gratefully acknowledged. JLW acknowledges support from CAPES and FAPEMIG (Brazil).

supplementary crystallographic information

Comment

N-(p-Chlorophenyl)acetamidine and related N-arylacetamidines (Shearer et al. 1997; Rousselet et al. 1993; Patai, 1975) were synthesized for use as reagents in the formation of 5-(difluoromethyl)-2-methyl-1-(substituted-phenyl)-1H-imidazoles, which are active anti-leishmanial compounds (Ferreira et al., 2007). Leishmaniasis is caused by several species of protozoan parasites transmitted by the bite of the female phlebotomine sand fly. This neglected disease is currently prevalent in four continents, being endemic in 88 countries, 72 of which are developing countries, threatening 350 millions worldwide (World Health Organization, 2010). The treatment of Leishmaniasis, currently, is dependent on old and highly toxic drugs (Croft et al., 2006). In addition, the development of clinical resistance and the increase of co-infections leishmaniasis AIDS, in some countries is causing further worries. Thus, the development of new, efficient, and safe drugs for the treatment of this disease is imperative (Ouellette et al., 2004; Croft et al., 2006; Ferreira et al., 2007). This contribution describes the synthesis and crystallographic characterisation of an N-(p-chlorophenyl)acetamidine derivative, (I).

The molecular structure of (I), Fig. 1, is twisted about the C1–N1 bond as seen in the value of the C2–C1–N1–C7 torsion angle of -118.6 (2) °; the dihedral angle formed between the benzene ring and ethanimidamide residue is 66.54 (14) °. The molecule has approximate mirror symmetry with the non-hydrogen atoms of the ethanimidamide lying on the putative plane and the benzene ring being bisected by the plane. The conformation about the C7═ N1 double bond [1.299 (3) Å] is Z.

The crystal packing is dominated by N–H···N and N–H···Cl hydrogen bonding interactions, Table 1. These lead to the formation of 22-membered {···HNH···ClC₄NCNH···ClC₄N···HNCN}₂ synthons that are connected into supramolecular arrays in the ac plane, Fig. 2; these have a zig-zag topology.

Experimental

To a stirred solution of p-chloroaniline (10.75 mmol) in acetonitrile (40 ml) was bubbled hydrogen chloride. A precipitate was formed immediately. The resulting suspension was refluxed and became homogeneous. Upon complete reaction, as shown by TLC, the mixture was rotary evaporated and the residue partitioned between CH₂Cl₂ and saturated aqueous NaHCO₃. The aqueous layer was washed (3 times) with CH₂Cl₂, and the combined organic layers were dried over sodium sulfate, filtered, and the filtrate concentrated under reduced pressure to yield a white solid; yield 96%, m.p. 389–390 K. The sample used in the X-ray study was slowly grown from an ethanol solution of (I). IR (KBr, cm^-1): 3451, 3295, 3079, 1640, 1586, 1482. ¹H NMR (500 MHz, CDCl₃): δ 1.99 (s, 3H, CH₃); 4.53 (br s, 2H, 2); 6.77 (d, 2H, J = 8.0 Hz); 7.24 (d, 2H, J = 8.0 Hz) p.p.m. ¹³C NMR (125 MHz, CDCl₃): δ 21.59 (CH₃); 122.5 121.1; 128.6; 144.6; 155.3 (H₂N—C=N) p.p.m. EI—MS (m/z): 168 (M⁺, 68%); 153 (M⁺-15, 38%); 127 (M⁺-41, 100%); 111 (M⁺ -57, 54%); 75 (M⁺-93, 42%).