1-[2-(2,4-Dichloro­phenyl)­pent­yl]-1H-1,2,4-triazole

Rizzoli, C.; Marku, E.; Greci, L.

doi:10.1107/S1600536809007120

organic compounds

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Volume 65| Part 4| April 2009| Page o663

doi:10.1107/S1600536809007120

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1-[2-(2,4-Dichlorophenyl)pentyl]-1H-1,2,4-triazole

Corrado Rizzoli,^a ^* Elda Marku ^b and Lucedio Greci ^c

^aDipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Universitá degli Studi di Parma, Viale G. P. Usberti 17/A, I-43100 Parma, Italy, ^bFakulteti i Shkencave të Natyrës, Departamenti i Kimise, Universiteti i Tiranes, Bulevardi "Zogu I", Tirana, Albania, and ^cDipartimento ISAC, Universitá Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona, Italy
^*Correspondence e-mail: corrado.rizzoli@unipr.it

(Received 25 February 2009; accepted 26 February 2009; online 6 March 2009)

The title compound, C₁₃H₁₅Cl₂N₃, also known as penconazole, crystallizes as a racemate. The dihedral angle between the benzene and triazole rings is 24.96 (13)°. In the crystal structure, molecules are linked into chains running parallel to the c axis by intermolecular C—H⋯N hydrogen-bonding interactions.

Related literature

For the synthesis and toxicity of the title compound, see: Maier et al. (1987 ); Worthing (1987 ); Tao et al. (2003 ). For the crystal structure of a related compound, see: Peeters et al. (1993 ).

Experimental

Crystal data

C₁₃H₁₅Cl₂N₃
M_r = 284.18
Monoclinic, C 2/c
a = 25.083 (8) Å
b = 10.763 (2) Å
c = 11.206 (3) Å
β = 105.654 (3)°
V = 2913.1 (13) Å³
Z = 8
Cu Kα radiation
μ = 3.89 mm⁻¹
T = 297 K
0.23 × 0.20 × 0.16 mm

Data collection

Siemens AED diffractometer
Absorption correction: empirical (refined from ΔF) (DIFABS; Walker & Stuart, 1983 ) T_min = 0.432, T_max = 0.538
2737 measured reflections
2611 independent reflections
1183 reflections with I > 2σ(I)
R_int = 0.060
3 standard reflections every 100 reflections intensity decay: 0.01%

Refinement

R[F² > 2σ(F²)] = 0.056
wR(F²) = 0.127
S = 0.99
2611 reflections
163 parameters
H-atom parameters constrained
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3A⋯N3ⁱ	0.97	2.52	3.489 (4)	174
Symmetry code: (i) $[x, -y+1, z+{\script{1\over 2}}]$ .

Data collection: AED (Belletti et al., 1993 ); cell refinement: AED; data reduction: AED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ) and SCHAKAL (Keller, 1997 ); software used to prepare material for publication: SHELXL97 and PARST95 (Nardelli, 1995 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809007120/hg2483sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809007120/hg2483Isup2.hkl

checkCIF report

Comment top

The synthesis of the title compound, I, commonly known as penconazole, was described years ago (Maier et al., 1987). Due to its ability to inhibit the development of fungi by interfering with sterol biosynthesis of their cell membranes, this product was introduced as an agriculture systemic fungicide affecting cucurbits, grapes, pome fruits and vegetables. The advantages of this compound is its low toxicity: acute oral dose (LD50) of 2125 mg/kg for rats (Worthing, 1987). More recently, penconazole was prepared by condensation of 2-(2,4-dichlorophenyl)-1-pentanole with 1,2,4-triazole (Tao et al., 2003), but this method also leads to the formation of 1-(1H-1,3,4-triazol-1-yl)-2-(2,4-dichlorophenyl)-pentane (II) as a by-product. In repeating this reaction, our purpose was the determination of the crystal structure of the desired compound I and the evaluation of the percentage of the by-product II.

The title compound (Fig. 1) crystallizes as a racemate. The triazole ring is substantially planar (maximum deviation from planarity 0.006 (3) Å for atom C2) and forms a dihedral angle of 24.96 (13)° with the benzene ring. The N—N (1.351 (3) Å) and C—N (mean value 1.328 (4) Å) bond lengths within the triazole ring are comparable with those observed in 6-[(4-chlorophenyl)(1H-1,2,4-triazol-1-yl)methyl]-1-methyl-1H-benzotriazole (vorozole; Peeters et al., 1993) and suggest electron delocalization over the ring. In the crystal structure, an intermolecular C—H···N hydrogen bonding interaction (Table 1) link the molecules into chains running parallel to the c axis (Fig. 2).

Related literature top

For the synthesis and toxicity of the title compound, see: Maier et al. (1987); Worthing (1987); Tao et al. (2003). For the crystal structure of a related compound, see: Peeters et al. (1993).

Experimental top

The title compound was prepared according to the literature reports (Tao et al., 2003). This method afforded compounds I and II in a 93:3 ratio. The two compounds were separated by chromatography on SiO₂ column eluting with cyclohexane/ethyl acetate (9:1 v/v). Crystals of the title compound suitable for X-ray analysis were obtained on slow evaporation of an n-pentane solution (m. p. 60–61°C). IR data, ν, cm^-1: 3060, 1597, 1448, 760, 746, 700. ¹H-NMR, δ in CDCL₃: 0.87 (t, 3H, –CH2CH3), 1.23 (sextet, 2H, -CH2CH3), 2.6–2.8 (m,2H, –CHCH2CH2CH3), 3.78 (1H, quintet, –CH2CHCH2-), 4.34 (d, -CH2CH<), 7.23 (1H, speudo-q, H-5, J=8.3 Hz, J=2.2 Hz), 7.38 (1H, d, H-3, J=2.2 Hz), 7.71 (s, 1H, triazolyl-H-3), 7.89 (s,1H, triazolyl-H-5). MS, Calcd for C₁₃H₁₅Cl₂N₃, 284.2; Found. M (%): 250 (12.72), 248 (36.93), 161 (63.69), 159 (100); no molecular ion peak was observed; the highest peaks are those corresponding to the loss of a chlorine atom. The ¹H-NMR spectrum of compound II shows a singlet at δ = 7.89 corresponding to the two equivalent H atoms of the 1,3,4-triazol-1-yl ring, the other part of the spectrum is strictly similar to that of compound I. Melting points were determined by an electrochemical apparatus and were uncorrected. ¹H-NMR spectra were recorded on a Varian Gemini 200 MHz. IR spectra were recorded in the solid state with a Perkin-Elmer MGX1 spectrophotometer equipped with Spectra Tech. Mass spectra were recorded with a Carlo Erba QMD 1000 mass spectrometer in positive EI mode.

Computing details top

Data collection: AED (Belletti et al., 1993); cell refinement: AED (Belletti et al., 1993); data reduction: AED (Belletti et al., 1993); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and SCHAKAL (Keller, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PARST95 (Nardelli, 1995).

Figures top

	Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Crystal packing of the title compound viewed approximately along the b axis. Intermolecular C—H···N hydrogen bonds are shown as dashed lines.
	Fig. 3. The structures of (I) and (II).

1-[2-(2,4-Dichlorophenyl)pentyl]-1H-1,2,4-triazole top

Crystal data top

C₁₃H₁₅Cl₂N₃	F(000) = 1184
M_r = 284.18	D_x = 1.296 Mg m⁻³
Monoclinic, C2/c	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: -C 2yc	Cell parameters from 48 reflections
a = 25.083 (8) Å	θ = 18.4–42.5°
b = 10.763 (2) Å	µ = 3.89 mm⁻¹
c = 11.206 (3) Å	T = 297 K
β = 105.654 (3)°	Block, colourless
V = 2913.1 (13) Å³	0.23 × 0.20 × 0.16 mm
Z = 8

Data collection top

Siemens AED diffractometer	1183 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.060
Graphite monochromator	θ_max = 67.9°, θ_min = 3.7°
θ/2θ scans	h = −29→28
Absorption correction: empirical (using intensity measurements) (DIFABS; Walker & Stuart, 1983)	k = −2→12
T_min = 0.432, T_max = 0.538	l = −5→13
2737 measured reflections	3 standard reflections every 100 reflections
2611 independent reflections	intensity decay: 0.01%

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.127	H-atom parameters constrained
S = 0.99	w = 1/[σ²(F_o²) + (0.0456P)²] where P = (F_o² + 2F_c²)/3
2611 reflections	(Δ/σ)_max < 0.001
163 parameters	Δρ_max = 0.34 e Å⁻³
0 restraints	Δρ_min = −0.27 e Å⁻³

Crystal data top

C₁₃H₁₅Cl₂N₃	V = 2913.1 (13) Å³
M_r = 284.18	Z = 8
Monoclinic, C2/c	Cu Kα radiation
a = 25.083 (8) Å	µ = 3.89 mm⁻¹
b = 10.763 (2) Å	T = 297 K
c = 11.206 (3) Å	0.23 × 0.20 × 0.16 mm
β = 105.654 (3)°

Data collection top

Siemens AED diffractometer	1183 reflections with I > 2σ(I)
Absorption correction: empirical (using intensity measurements) (DIFABS; Walker & Stuart, 1983)	R_int = 0.060
T_min = 0.432, T_max = 0.538	3 standard reflections every 100 reflections
2737 measured reflections	intensity decay: 0.01%
2611 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.056	0 restraints
wR(F²) = 0.127	H-atom parameters constrained
S = 0.99	Δρ_max = 0.34 e Å⁻³
2611 reflections	Δρ_min = −0.27 e Å⁻³
163 parameters

Special details top

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 > σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Cl1	0.08070 (6)	0.51687 (9)	0.93474 (12)	0.1422 (6)
Cl2	0.08744 (5)	0.18168 (11)	1.28987 (10)	0.1305 (5)
N1	0.22774 (10)	0.3780 (2)	0.7443 (2)	0.0595 (7)
N2	0.24356 (12)	0.3032 (2)	0.6633 (2)	0.0757 (8)
N3	0.25582 (12)	0.5043 (2)	0.6210 (3)	0.0815 (9)
C1	0.25951 (15)	0.3839 (3)	0.5932 (3)	0.0808 (10)
H1	0.2728	0.3591	0.5270	0.097*
C2	0.23549 (13)	0.4960 (3)	0.7196 (3)	0.0714 (9)
H2	0.2279	0.5634	0.7644	0.086*
C3	0.20829 (13)	0.3285 (3)	0.8460 (3)	0.0638 (8)
H3A	0.2230	0.3790	0.9192	0.077*
H3B	0.2226	0.2449	0.8646	0.077*
C4	0.14554 (13)	0.3253 (3)	0.8180 (3)	0.0666 (8)
H4	0.1313	0.4086	0.7921	0.080*
C5	0.13060 (12)	0.2927 (3)	0.9380 (3)	0.0648 (8)
C6	0.10164 (15)	0.3713 (3)	0.9946 (3)	0.0807 (10)
C7	0.08852 (16)	0.3387 (3)	1.1047 (4)	0.0927 (11)
H7	0.0695	0.3937	1.1424	0.111*
C8	0.10441 (15)	0.2235 (4)	1.1558 (3)	0.0790 (10)
C9	0.13257 (14)	0.1450 (3)	1.1013 (3)	0.0787 (10)
H9	0.1435	0.0680	1.1372	0.094*
C10	0.14543 (13)	0.1774 (3)	0.9930 (3)	0.0724 (9)
H10	0.1643	0.1211	0.9562	0.087*
C11	0.11930 (14)	0.2323 (3)	0.7113 (3)	0.0830 (10)
H11A	0.1315	0.2537	0.6389	0.100*
H11B	0.1326	0.1492	0.7368	0.100*
C12	0.05814 (16)	0.2321 (4)	0.6773 (3)	0.1057 (13)
H12A	0.0450	0.3152	0.6514	0.127*
H12B	0.0460	0.2115	0.7501	0.127*
C13	0.03234 (16)	0.1433 (4)	0.5764 (4)	0.1191 (15)
H131	−0.0072	0.1482	0.5589	0.179*
H132	0.0442	0.0604	0.6020	0.179*
H133	0.0434	0.1640	0.5032	0.179*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.2339 (15)	0.0687 (6)	0.1461 (10)	0.0447 (8)	0.0895 (10)	0.0118 (7)
Cl2	0.1620 (11)	0.1516 (11)	0.0905 (7)	−0.0169 (8)	0.0558 (7)	0.0066 (7)
N1	0.0728 (18)	0.0384 (12)	0.0602 (15)	−0.0030 (12)	0.0061 (13)	−0.0050 (12)
N2	0.103 (2)	0.0486 (14)	0.0760 (18)	−0.0110 (15)	0.0248 (16)	−0.0087 (14)
N3	0.101 (2)	0.0588 (17)	0.081 (2)	−0.0131 (15)	0.0183 (18)	0.0088 (15)
C1	0.111 (3)	0.0566 (19)	0.075 (2)	−0.016 (2)	0.026 (2)	−0.0020 (18)
C2	0.084 (3)	0.0447 (17)	0.079 (2)	−0.0054 (16)	0.0105 (19)	−0.0048 (17)
C3	0.076 (2)	0.0485 (16)	0.0612 (19)	−0.0073 (15)	0.0083 (16)	0.0029 (15)
C4	0.072 (2)	0.0545 (18)	0.067 (2)	0.0001 (16)	0.0072 (17)	0.0065 (16)
C5	0.064 (2)	0.0564 (18)	0.066 (2)	−0.0038 (16)	0.0049 (16)	−0.0013 (16)
C6	0.105 (3)	0.057 (2)	0.082 (2)	−0.003 (2)	0.027 (2)	−0.0030 (19)
C7	0.109 (3)	0.079 (3)	0.094 (3)	−0.006 (2)	0.035 (2)	−0.019 (2)
C8	0.086 (3)	0.089 (3)	0.064 (2)	−0.015 (2)	0.0244 (19)	0.002 (2)
C9	0.079 (2)	0.074 (2)	0.079 (2)	−0.0020 (19)	0.014 (2)	0.019 (2)
C10	0.073 (2)	0.066 (2)	0.076 (2)	0.0035 (17)	0.0154 (18)	0.0082 (18)
C11	0.084 (3)	0.094 (3)	0.060 (2)	−0.011 (2)	0.0009 (18)	−0.0074 (19)
C12	0.096 (3)	0.121 (3)	0.091 (3)	−0.026 (3)	0.011 (2)	−0.011 (3)
C13	0.095 (3)	0.140 (4)	0.100 (3)	−0.016 (3)	−0.013 (2)	−0.030 (3)

Geometric parameters (Å, º) top

Cl1—C6	1.729 (3)	C5—C10	1.391 (4)
Cl2—C8	1.728 (3)	C6—C7	1.404 (5)
N1—C2	1.326 (3)	C7—C8	1.379 (4)
N1—N2	1.351 (3)	C7—H7	0.9300
N1—C3	1.457 (3)	C8—C9	1.348 (4)
N2—C1	1.304 (4)	C9—C10	1.382 (4)
N3—C2	1.339 (4)	C9—H9	0.9300
N3—C1	1.342 (4)	C10—H10	0.9300
C1—H1	0.9300	C11—C12	1.478 (4)
C2—H2	0.9300	C11—H11A	0.9700
C3—C4	1.520 (4)	C11—H11B	0.9700
C3—H3A	0.9700	C12—C13	1.488 (5)
C3—H3B	0.9700	C12—H12A	0.9700
C4—C5	1.530 (4)	C12—H12B	0.9700
C4—C11	1.562 (4)	C13—H131	0.9600
C4—H4	0.9800	C13—H132	0.9600
C5—C6	1.377 (4)	C13—H133	0.9600

C2—N1—N2	110.2 (3)	C8—C7—H7	120.7
C2—N1—C3	127.8 (3)	C6—C7—H7	120.7
N2—N1—C3	122.0 (2)	C9—C8—C7	120.2 (3)
C1—N2—N1	101.6 (2)	C9—C8—Cl2	120.9 (3)
C2—N3—C1	101.1 (3)	C7—C8—Cl2	118.9 (3)
N2—C1—N3	116.8 (3)	C8—C9—C10	121.0 (3)
N2—C1—H1	121.6	C8—C9—H9	119.5
N3—C1—H1	121.6	C10—C9—H9	119.5
N1—C2—N3	110.2 (3)	C9—C10—C5	121.1 (3)
N1—C2—H2	124.9	C9—C10—H10	119.5
N3—C2—H2	124.9	C5—C10—H10	119.5
N1—C3—C4	113.2 (2)	C12—C11—C4	113.1 (3)
N1—C3—H3A	108.9	C12—C11—H11A	109.0
C4—C3—H3A	108.9	C4—C11—H11A	109.0
N1—C3—H3B	108.9	C12—C11—H11B	109.0
C4—C3—H3B	108.9	C4—C11—H11B	109.0
H3A—C3—H3B	107.8	H11A—C11—H11B	107.8
C3—C4—C5	108.0 (2)	C11—C12—C13	113.9 (3)
C3—C4—C11	111.8 (3)	C11—C12—H12A	108.8
C5—C4—C11	111.9 (2)	C13—C12—H12A	108.8
C3—C4—H4	108.3	C11—C12—H12B	108.8
C5—C4—H4	108.3	C13—C12—H12B	108.8
C11—C4—H4	108.3	H12A—C12—H12B	107.7
C6—C5—C10	117.1 (3)	C12—C13—H131	109.5
C6—C5—C4	123.3 (3)	C12—C13—H132	109.5
C10—C5—C4	119.6 (3)	H131—C13—H132	109.5
C5—C6—C7	122.0 (3)	C12—C13—H133	109.5
C5—C6—Cl1	121.4 (3)	H131—C13—H133	109.5
C7—C6—Cl1	116.7 (3)	H132—C13—H133	109.5
C8—C7—C6	118.7 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3A···N3ⁱ	0.97	2.52	3.489 (4)	174

Symmetry code: (i) x, −y+1, z+1/2.

Experimental details

Crystal data
Chemical formula	C₁₃H₁₅Cl₂N₃
M_r	284.18
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	297
a, b, c (Å)	25.083 (8), 10.763 (2), 11.206 (3)
β (°)	105.654 (3)
V (Å³)	2913.1 (13)
Z	8
Radiation type	Cu Kα
µ (mm⁻¹)	3.89
Crystal size (mm)	0.23 × 0.20 × 0.16

Data collection
Diffractometer	Siemens AED diffractometer
Absorption correction	Empirical (using intensity measurements) (DIFABS; Walker & Stuart, 1983)
T_min, T_max	0.432, 0.538
No. of measured, independent and observed [I > 2σ(I)] reflections	2737, 2611, 1183
R_int	0.060
(sin θ/λ)_max (Å⁻¹)	0.601

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.056, 0.127, 0.99
No. of reflections	2611
No. of parameters	163
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.34, −0.27

Computer programs: AED (Belletti et al., 1993), SHELXS97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and SCHAKAL (Keller, 1997), SHELXL97 (Sheldrick, 2008) and PARST95 (Nardelli, 1995).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3A···N3ⁱ	0.97	2.52	3.489 (4)	174

Symmetry code: (i) x, −y+1, z+1/2.

Acknowledgements

Financial support from the Universitá Politecnica delle Marche and the Universitá degli Studi di Parma is gratefully acknowledged.

References

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