organic compounds
2-(1,2,3,4-Tetrahydro-1-naphthyl)imidazolium chloride monohydrate
aDipartimento di Scienze Farmaceutiche, Universitá di Firenze, Via U. Schiff 6, I-50019 Sesto Fiorentino, Firenze, Italy, and bCentro di Cristallografia, Universitá di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Firenze, Italy
*Correspondence e-mail: samuele.ciattini@unifi.it
In the title compound, C13H15N2+·Cl−·H2O, the ions and water molecules are connected by N—H⋯Cl, O—H⋯Cl, NH⋯Cl⋯HO, NH⋯Cl⋯HN and OH⋯Cl⋯HO interactions, forming discrete D(2) and D21(3) chains, C21(6) chains and R42(8) rings, leading to a neutral two-dimensional network. The is further stabilized by π–π stacking interactions [centroid–centroid distance = 3.652 (11) Å].
Related literature
The title compound is a by-product obtained in the preparation of the popular decongestant tetrahydrozoline hydrochloride and differs from the main product in the presence of an aromatic imidazole instead of a dihydroimidazole group. For the structure of the tetrahydrozoline main product, see: Ghose & Dattagupta (1989); Ciattini et al. (2010). For the identification of the nature of the title compound, see: Bartolucci (2010). For hydrogen-bond motifs, see: Bernstein et al. (1995).
Experimental
Crystal data
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Refinement
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Data collection: CrysAlis PRO CCD (Oxford Diffraction, 2006); cell CrysAlis PRO CCD; data reduction: CrysAlis PRO RED (Oxford Diffraction, 2006); program(s) used to solve structure: SIR2004 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 and PARST (Nardelli, 1995).
Supporting information
https://doi.org/10.1107/S1600536810030473/bx2288sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810030473/bx2288Isup2.hkl
Samples of the compound, made available from concomitant studies (Bartolucci, 2010), were obtained in suitable form for X-ray
by slow evaporation from methanolic solutions.In the final
cycles non-hydrogen atoms were assigned anisotropic thermal parameters and H atoms had Uiso(H) = 1.2 Ueq(C, N), or Uiso(H) = 1.5 Ueq(O) for the water H atoms. Hydrogen atoms were placed in geometrically generated positions, riding, except for those of the water molecule, whose positions were refined with a restraint on O—H distances (0.86 (1) Å final value). Assigned C—H: tertiary CH 1.00 Å, secondary CH2 0.99 Å, aromatic CH 0.95 Å. Aromatic N—H: 0.88 Å.The industrial preparation of the widely used drug tetrahydrozolyne hydrochloride, 2-(1,2,3,4-tetrahydro-naphthalen-1-yl)-4,5- dihydro-1 H-imidazole hydrochloride, whose structure was reported several years ago (Ghose & Dattagupta, 1989), is generally accompanied by tiny amounts of an impurity (the title compound), whose nature has been identified (Bartolucci, 2010), but whose structure awaited investigation.
The trace byproduct, strictly related to the tetrahydrozolyne molecule, features an imidazole, rather than a dihydroimidazole ring. The structure of the present hydrochloride consists of cations, generated by N-protonation of the above imidazole derivative, chloride anions and solvate water molecules in 1:1:1 ratios. The content of the π-π stacking interactions, (Cg1-Cg2= 3.652 (11) Å, α = 6.59 (10)° (Cg1 = N1/C1-C2/N2/C3 and Cg2 = C8-C13) and this interaction is not observed in the of the tetrahydrozoline main product (Ghose & Dattagupta, 1989; Ciattini et al., 2010).
is shown in Fig. 1. In the course of our investigations on these species, the structure of the main product of the preparation, already known (Ghose & Dattagupta, 1989), has been refined against low–temperature data and deposited at the Cambridge Structural database (deposition number CCDC 782942 [Ciattini et al., (2010)]. In spite of the above difference between molecules of the main product and of the impurity and irrespective of different packing modes in the two structures, the overall molecular geometries are closely similar: e.g., the dihedral angle formed by the best planes through the benzene and imidazole rings is 88.62 (5)° in the cation of the present structure and 88.00 (6)° in that of the tetrahydrozoline hydrochloride drug (170 K data).The structure of (I), C13H15N2+.Cl– .H2O, comprises discrete ions and water molecules which are interconnected by N—H···Cl, O—H···Cl, NH···Cl···HO, NH···Cl···HN and OH···Cl···HO interactions to form discrete chains D(2), D21(3); chains , C12(6) and rings R42(8) motifs (Bernstein et al., 1995), leading to a neutral bidimensional- network. The is further stabilized byThe title compound is a by-product obtained in the preparation of the popular decongestant tetrahydrozoline hydrochloride and differs from the main product in the presence of an aromatic imidazole instead of a dihydroimidazole group. For the structure of the tetrahydrozoline main product, see: Ghose & Dattagupta (1989); Ciattini et al. (2010). For the identification of the nature of the title compound, see: Bartolucci (2010). For hydrogen-bond motifs, see: Bernstein et al. (1995).
Data collection: CrysAlis PRO CCD (Oxford Diffraction, 2006); cell
CrysAlis PRO CCD (Oxford Diffraction, 2006); data reduction: CrysAlis PRO RED (Oxford Diffraction, 2006); program(s) used to solve structure: SIR2004 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PARST (Nardelli, 1995).C13H15N2+·Cl−·H2O | F(000) = 536 |
Mr = 252.74 | Dx = 1.281 Mg m−3 |
Monoclinic, P21/n | Cu Kα radiation, λ = 1.54180 Å |
Hall symbol: -P 2yn | Cell parameters from 3348 reflections |
a = 9.8299 (1) Å | θ = 4.2–61.4° |
b = 12.6671 (2) Å | µ = 2.46 mm−1 |
c = 10.5375 (2) Å | T = 173 K |
β = 92.666 (1)° | Irregularly shaped prism, colourless |
V = 1310.67 (3) Å3 | 0.40 × 0.25 × 0.10 mm |
Z = 4 |
Oxford Diffraction Xcalibur PX Ultra CCD diffractometer | 1981 independent reflections |
Radiation source: fine-focus sealed tube | 1883 reflections with I > 2σ(I) |
Oxford Diffraction, Enhance ULTRA assembly monochromator | Rint = 0.011 |
Detector resolution: 8.1241 pixels mm-1 | θmax = 61.6°, θmin = 5.5° |
ω scans | h = −11→6 |
Absorption correction: multi-scan (ABSPACK; Oxford Diffraction, 2006) | k = −14→12 |
Tmin = 0.594, Tmax = 1.000 | l = −9→11 |
3831 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.033 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.091 | w = 1/[σ2(Fo2) + (0.0459P)2 + 0.6835P] where P = (Fo2 + 2Fc2)/3 |
S = 1.09 | (Δ/σ)max < 0.001 |
1981 reflections | Δρmax = 0.21 e Å−3 |
161 parameters | Δρmin = −0.33 e Å−3 |
2 restraints | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0042 (10) |
C13H15N2+·Cl−·H2O | V = 1310.67 (3) Å3 |
Mr = 252.74 | Z = 4 |
Monoclinic, P21/n | Cu Kα radiation |
a = 9.8299 (1) Å | µ = 2.46 mm−1 |
b = 12.6671 (2) Å | T = 173 K |
c = 10.5375 (2) Å | 0.40 × 0.25 × 0.10 mm |
β = 92.666 (1)° |
Oxford Diffraction Xcalibur PX Ultra CCD diffractometer | 1981 independent reflections |
Absorption correction: multi-scan (ABSPACK; Oxford Diffraction, 2006) | 1883 reflections with I > 2σ(I) |
Tmin = 0.594, Tmax = 1.000 | Rint = 0.011 |
3831 measured reflections | θmax = 61.6° |
R[F2 > 2σ(F2)] = 0.033 | 2 restraints |
wR(F2) = 0.091 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.09 | Δρmax = 0.21 e Å−3 |
1981 reflections | Δρmin = −0.33 e Å−3 |
161 parameters |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
Cl | 0.72704 (5) | 0.40149 (4) | 0.00302 (4) | 0.0364 (2) | |
N1 | 0.62280 (14) | 0.24302 (12) | 0.79789 (14) | 0.0306 (4) | |
H14 | 0.6564 | 0.2871 | 0.8558 | 0.037* | |
N2 | 0.48201 (14) | 0.15944 (11) | 0.67424 (13) | 0.0284 (4) | |
H15 | 0.4056 | 0.1383 | 0.6354 | 0.034* | |
C1 | 0.69789 (19) | 0.17205 (15) | 0.73092 (18) | 0.0345 (4) | |
H1 | 0.7937 | 0.1622 | 0.7383 | 0.041* | |
C2 | 0.60936 (18) | 0.11937 (15) | 0.65322 (17) | 0.0325 (4) | |
H2 | 0.6305 | 0.0651 | 0.5951 | 0.039* | |
C3 | 0.49175 (17) | 0.23477 (13) | 0.76179 (15) | 0.0263 (4) | |
C4 | 0.37597 (17) | 0.29425 (14) | 0.81497 (16) | 0.0274 (4) | |
H4 | 0.4159 | 0.3502 | 0.8723 | 0.033* | |
C5 | 0.29045 (19) | 0.34994 (15) | 0.70929 (18) | 0.0330 (4) | |
H51 | 0.3418 | 0.4108 | 0.6771 | 0.040* | |
H52 | 0.2720 | 0.3004 | 0.6378 | 0.040* | |
C6 | 0.15650 (19) | 0.38812 (15) | 0.75959 (19) | 0.0357 (5) | |
H61 | 0.1051 | 0.4282 | 0.6925 | 0.043* | |
H62 | 0.1749 | 0.4359 | 0.8328 | 0.043* | |
C7 | 0.07197 (19) | 0.29466 (16) | 0.80081 (19) | 0.0377 (5) | |
H71 | −0.0086 | 0.3211 | 0.8440 | 0.045* | |
H72 | 0.0389 | 0.2549 | 0.7246 | 0.045* | |
C8 | 0.15091 (18) | 0.22119 (14) | 0.88886 (17) | 0.0300 (4) | |
C9 | 0.29331 (18) | 0.22005 (13) | 0.89655 (16) | 0.0275 (4) | |
C10 | 0.3616 (2) | 0.15248 (16) | 0.98209 (17) | 0.0359 (5) | |
H10 | 0.4583 | 0.1524 | 0.9875 | 0.043* | |
C11 | 0.2911 (2) | 0.08543 (17) | 1.05936 (19) | 0.0424 (5) | |
H11 | 0.3389 | 0.0398 | 1.1174 | 0.051* | |
C12 | 0.1495 (2) | 0.08569 (16) | 1.05108 (19) | 0.0417 (5) | |
H12 | 0.0998 | 0.0399 | 1.1033 | 0.050* | |
C13 | 0.0822 (2) | 0.15226 (16) | 0.96731 (18) | 0.0380 (5) | |
H13 | −0.0146 | 0.1516 | 0.9623 | 0.046* | |
O | 0.46819 (17) | 0.45111 (15) | 0.17630 (17) | 0.0595 (5) | |
H16 | 0.415 (3) | 0.487 (2) | 0.125 (2) | 0.089* | |
H17 | 0.539 (2) | 0.435 (3) | 0.136 (3) | 0.089* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl | 0.0348 (3) | 0.0341 (3) | 0.0390 (3) | −0.00069 (18) | −0.00995 (19) | 0.00005 (18) |
N1 | 0.0251 (8) | 0.0341 (8) | 0.0325 (8) | −0.0043 (6) | −0.0007 (6) | −0.0007 (7) |
N2 | 0.0249 (8) | 0.0308 (8) | 0.0293 (8) | −0.0026 (6) | 0.0009 (6) | −0.0017 (6) |
C1 | 0.0259 (9) | 0.0394 (10) | 0.0384 (10) | 0.0039 (8) | 0.0045 (8) | 0.0050 (9) |
C2 | 0.0321 (10) | 0.0330 (10) | 0.0331 (10) | 0.0061 (8) | 0.0075 (8) | 0.0021 (8) |
C3 | 0.0262 (9) | 0.0269 (9) | 0.0259 (9) | −0.0048 (7) | 0.0021 (7) | 0.0025 (7) |
C4 | 0.0253 (9) | 0.0277 (9) | 0.0294 (9) | −0.0031 (7) | 0.0033 (7) | −0.0049 (7) |
C5 | 0.0328 (10) | 0.0299 (10) | 0.0362 (10) | 0.0012 (8) | 0.0028 (8) | 0.0013 (8) |
C6 | 0.0330 (10) | 0.0319 (10) | 0.0419 (11) | 0.0049 (8) | −0.0007 (8) | −0.0060 (8) |
C7 | 0.0268 (9) | 0.0419 (11) | 0.0444 (11) | −0.0005 (8) | 0.0021 (8) | −0.0083 (9) |
C8 | 0.0289 (9) | 0.0311 (9) | 0.0306 (9) | −0.0048 (8) | 0.0060 (7) | −0.0111 (8) |
C9 | 0.0295 (9) | 0.0283 (9) | 0.0251 (9) | −0.0033 (7) | 0.0046 (7) | −0.0065 (7) |
C10 | 0.0324 (10) | 0.0438 (11) | 0.0318 (10) | −0.0018 (8) | 0.0042 (8) | 0.0012 (9) |
C11 | 0.0528 (13) | 0.0426 (12) | 0.0323 (10) | −0.0025 (10) | 0.0054 (9) | 0.0043 (9) |
C12 | 0.0505 (13) | 0.0408 (11) | 0.0351 (11) | −0.0170 (10) | 0.0143 (9) | −0.0056 (9) |
C13 | 0.0331 (10) | 0.0427 (11) | 0.0388 (11) | −0.0110 (9) | 0.0098 (8) | −0.0126 (9) |
O | 0.0457 (10) | 0.0654 (11) | 0.0674 (11) | 0.0046 (8) | 0.0037 (8) | 0.0186 (9) |
N1—C3 | 1.330 (2) | C6—H61 | 0.9900 |
N1—C1 | 1.378 (2) | C6—H62 | 0.9900 |
N1—H14 | 0.8800 | C7—C8 | 1.504 (3) |
N2—C3 | 1.328 (2) | C7—H71 | 0.9900 |
N2—C2 | 1.378 (2) | C7—H72 | 0.9900 |
N2—H15 | 0.8800 | C8—C13 | 1.398 (3) |
C1—C2 | 1.344 (3) | C8—C9 | 1.398 (3) |
C1—H1 | 0.9500 | C9—C10 | 1.392 (3) |
C2—H2 | 0.9500 | C10—C11 | 1.384 (3) |
C3—C4 | 1.495 (2) | C10—H10 | 0.9500 |
C4—C9 | 1.532 (2) | C11—C12 | 1.390 (3) |
C4—C5 | 1.535 (3) | C11—H11 | 0.9500 |
C4—H4 | 1.0000 | C12—C13 | 1.369 (3) |
C5—C6 | 1.521 (3) | C12—H12 | 0.9500 |
C5—H51 | 0.9900 | C13—H13 | 0.9500 |
C5—H52 | 0.9900 | O—H16 | 0.862 (10) |
C6—C7 | 1.521 (3) | O—H17 | 0.861 (10) |
C3—N1—C1 | 109.69 (15) | C7—C6—H61 | 109.6 |
C3—N1—H14 | 125.2 | C5—C6—H62 | 109.6 |
C1—N1—H14 | 125.2 | C7—C6—H62 | 109.6 |
C3—N2—C2 | 109.86 (15) | H61—C6—H62 | 108.1 |
C3—N2—H15 | 125.1 | C8—C7—C6 | 112.62 (15) |
C2—N2—H15 | 125.1 | C8—C7—H71 | 109.1 |
C2—C1—N1 | 106.78 (16) | C6—C7—H71 | 109.1 |
C2—C1—H1 | 126.6 | C8—C7—H72 | 109.1 |
N1—C1—H1 | 126.6 | C6—C7—H72 | 109.1 |
C1—C2—N2 | 106.64 (16) | H71—C7—H72 | 107.8 |
C1—C2—H2 | 126.7 | C13—C8—C9 | 117.99 (18) |
N2—C2—H2 | 126.7 | C13—C8—C7 | 120.10 (17) |
N2—C3—N1 | 107.02 (15) | C9—C8—C7 | 121.90 (16) |
N2—C3—C4 | 126.23 (15) | C10—C9—C8 | 119.65 (16) |
N1—C3—C4 | 126.66 (15) | C10—C9—C4 | 119.22 (15) |
C3—C4—C9 | 109.51 (14) | C8—C9—C4 | 121.11 (16) |
C3—C4—C5 | 111.11 (14) | C11—C10—C9 | 121.25 (18) |
C9—C4—C5 | 113.71 (14) | C11—C10—H10 | 119.4 |
C3—C4—H4 | 107.4 | C9—C10—H10 | 119.4 |
C9—C4—H4 | 107.4 | C10—C11—C12 | 119.2 (2) |
C5—C4—H4 | 107.4 | C10—C11—H11 | 120.4 |
C6—C5—C4 | 110.30 (15) | C12—C11—H11 | 120.4 |
C6—C5—H51 | 109.6 | C13—C12—C11 | 119.65 (18) |
C4—C5—H51 | 109.6 | C13—C12—H12 | 120.2 |
C6—C5—H52 | 109.6 | C11—C12—H12 | 120.2 |
C4—C5—H52 | 109.6 | C12—C13—C8 | 122.23 (18) |
H51—C5—H52 | 108.1 | C12—C13—H13 | 118.9 |
C5—C6—C7 | 110.20 (15) | C8—C13—H13 | 118.9 |
C5—C6—H61 | 109.6 | H16—O—H17 | 107 (3) |
C3—N1—C1—C2 | −0.4 (2) | C6—C7—C8—C9 | −19.8 (2) |
N1—C1—C2—N2 | 0.1 (2) | C13—C8—C9—C10 | −0.9 (2) |
C3—N2—C2—C1 | 0.2 (2) | C7—C8—C9—C10 | 178.28 (16) |
C2—N2—C3—N1 | −0.50 (19) | C13—C8—C9—C4 | −179.19 (15) |
C2—N2—C3—C4 | −177.17 (16) | C7—C8—C9—C4 | 0.0 (2) |
C1—N1—C3—N2 | 0.56 (19) | C3—C4—C9—C10 | 44.9 (2) |
C1—N1—C3—C4 | 177.21 (16) | C5—C4—C9—C10 | 169.90 (16) |
N2—C3—C4—C9 | 69.1 (2) | C3—C4—C9—C8 | −136.78 (16) |
N1—C3—C4—C9 | −106.93 (19) | C5—C4—C9—C8 | −11.8 (2) |
N2—C3—C4—C5 | −57.3 (2) | C8—C9—C10—C11 | 0.5 (3) |
N1—C3—C4—C5 | 126.63 (18) | C4—C9—C10—C11 | 178.83 (17) |
C3—C4—C5—C6 | 166.88 (15) | C9—C10—C11—C12 | 0.1 (3) |
C9—C4—C5—C6 | 42.8 (2) | C10—C11—C12—C13 | −0.2 (3) |
C4—C5—C6—C7 | −63.2 (2) | C11—C12—C13—C8 | −0.2 (3) |
C5—C6—C7—C8 | 51.0 (2) | C9—C8—C13—C12 | 0.8 (3) |
C6—C7—C8—C13 | 159.38 (16) | C7—C8—C13—C12 | −178.46 (17) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H14···Cli | 0.88 | 2.21 | 3.0897 (16) | 176 |
N2—H15···Clii | 0.88 | 2.25 | 3.1164 (15) | 169 |
O—H17···Cl | 0.86 (1) | 2.41 (1) | 3.2612 (18) | 173 (3) |
O—H16···Cliii | 0.86 (1) | 2.37 (1) | 3.2252 (17) | 175 (3) |
Symmetry codes: (i) x, y, z+1; (ii) x−1/2, −y+1/2, z+1/2; (iii) −x+1, −y+1, −z. |
Experimental details
Crystal data | |
Chemical formula | C13H15N2+·Cl−·H2O |
Mr | 252.74 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 173 |
a, b, c (Å) | 9.8299 (1), 12.6671 (2), 10.5375 (2) |
β (°) | 92.666 (1) |
V (Å3) | 1310.67 (3) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 2.46 |
Crystal size (mm) | 0.40 × 0.25 × 0.10 |
Data collection | |
Diffractometer | Oxford Diffraction Xcalibur PX Ultra CCD diffractometer |
Absorption correction | Multi-scan (ABSPACK; Oxford Diffraction, 2006) |
Tmin, Tmax | 0.594, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3831, 1981, 1883 |
Rint | 0.011 |
θmax (°) | 61.6 |
(sin θ/λ)max (Å−1) | 0.570 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.091, 1.09 |
No. of reflections | 1981 |
No. of parameters | 161 |
No. of restraints | 2 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.21, −0.33 |
Computer programs: CrysAlis PRO CCD (Oxford Diffraction, 2006), CrysAlis PRO RED (Oxford Diffraction, 2006), SIR2004 (Altomare et al., 1999), ORTEP-3 (Farrugia, 1997), SHELXL97 (Sheldrick, 2008) and PARST (Nardelli, 1995).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H14···Cli | 0.88 | 2.21 | 3.0897 (16) | 176.2 |
N2—H15···Clii | 0.88 | 2.25 | 3.1164 (15) | 168.9 |
O—H17···Cl | 0.861 (10) | 2.405 (11) | 3.2612 (18) | 173 (3) |
O—H16···Cliii | 0.862 (10) | 2.366 (11) | 3.2252 (17) | 175 (3) |
Symmetry codes: (i) x, y, z+1; (ii) x−1/2, −y+1/2, z+1/2; (iii) −x+1, −y+1, −z. |
Acknowledgements
The authors acknowledge financial support from the Italian Ministero dell'Istruzione, dell'Universitá e della Ricerca. Availability of instrumentation at the CRIST Centre of the University of Florence is acknowledged.
References
Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115–119. Web of Science CrossRef CAS IUCr Journals Google Scholar
Bartolucci, G. (2010). Private communication. Google Scholar
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Ciattini, S., Bruni, B., Bartolucci, G. & Coran, S. A. (2010). Private communication (number 1078) to the Cambridge Structural Database. Cambridge Crystallographic Data Centre, Cambridge, England. Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Ghose, S. & Dattagupta, J. K. (1989). Acta Cryst. C45, 1522–1524. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Nardelli, M. (1995). J. Appl. Cryst. 28, 659. CrossRef IUCr Journals Google Scholar
Oxford Diffraction (2006). CrysAlis PRO CCD, CrysAlis PRO RED and ABSPACK in CrysAlis PRO RED. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
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The industrial preparation of the widely used drug tetrahydrozolyne hydrochloride, 2-(1,2,3,4-tetrahydro-naphthalen-1-yl)-4,5- dihydro-1 H-imidazole hydrochloride, whose structure was reported several years ago (Ghose & Dattagupta, 1989), is generally accompanied by tiny amounts of an impurity (the title compound), whose nature has been identified (Bartolucci, 2010), but whose structure awaited investigation.
The trace byproduct, strictly related to the tetrahydrozolyne molecule, features an imidazole, rather than a dihydroimidazole ring. The structure of the present hydrochloride consists of cations, generated by N-protonation of the above imidazole derivative, chloride anions and solvate water molecules in 1:1:1 ratios. The content of the asymmetric unit is shown in Fig. 1. In the course of our investigations on these species, the structure of the main product of the preparation, already known (Ghose & Dattagupta, 1989), has been refined against low–temperature data and deposited at the Cambridge Structural database (deposition number CCDC 782942 [Ciattini et al., (2010)]. In spite of the above difference between molecules of the main product and of the impurity and irrespective of different packing modes in the two structures, the overall molecular geometries are closely similar: e.g., the dihedral angle formed by the best planes through the benzene and imidazole rings is 88.62 (5)° in the cation of the present structure and 88.00 (6)° in that of the tetrahydrozoline hydrochloride drug (170 K data).The structure of (I), C13H15N2+.Cl– .H2O, comprises discrete ions and water molecules which are interconnected by N—H···Cl, O—H···Cl, NH···Cl···HO, NH···Cl···HN and OH···Cl···HO interactions to form discrete chains D(2), D21(3); chains , C12(6) and rings R42(8) motifs (Bernstein et al., 1995), leading to a neutral bidimensional- network. The crystal structure is further stabilized by π-π stacking interactions, (Cg1-Cg2= 3.652 (11) Å, α = 6.59 (10)° (Cg1 = N1/C1-C2/N2/C3 and Cg2 = C8-C13) and this interaction is not observed in the crystal structure of the tetrahydrozoline main product (Ghose & Dattagupta, 1989; Ciattini et al., 2010).