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Chlordiazepoxide di­chloro­methane monosolvate

aDivision of Applied Physical Chemistry, School of Chemical Science and Engineering, 100 44 Stockholm, Sweden
*Correspondence e-mail: afischer@kth.se

(Received 4 March 2012; accepted 5 March 2012; online 10 March 2012)

In the title compound (systematic name: 7-chloro-2-methyl­amino-5-phenyl-3H-1,4-benzodiazepine 4-oxide dichloro­meth­ane monosolvate), C16H14ClN3O·CH2Cl2, the seven-membered ring adopts a boat conformation with the CH2 group as the prow and the two aromatic C atoms as the stern. The dihedral angle between the benzene rings is 75.25 (6)°. The crystal structure features centrosymmetric pairs of chlordiazepoxide mol­ecules linked by pairs of N—H⋯O hydrogen bonds, which generate R22(12) loops.

Related literature

For the synthesis of chlordiazepoxide, see: Sternbach et al. (1961[Sternbach, L. H., Reeder, E., Keller, O. & Metlesics, W. (1961). J. Org. Chem. 26, 4488-4497.]). For the structure of chlordiazepoxide, see: Bertolasi et al. (1982[Bertolasi, V., Sacerdoti, M., Gilli, G. & Borea, P. A. (1982). Acta Cryst. B38, 1768-1772.]). For the structure of a second polymorph of chlordiazepoxide, see: Singh et al. (1998[Singh, D., Marshall, P. V., Shields, L. & York, P. (1998). J. Pharm. Sci. 87, 655-662.]). For the structure of chlordiazepoxide hydro­chloride, see: Herrnstadt et al. (1979[Herrnstadt, C., Mootz, D., Wunderlich, H. & Möhrle, H. (1979). J. Chem. Soc. Perkin Trans. 2, pp. 735-740.]). For the early history of benzopdiazepines, see: Sternbach (1979[Sternbach, L. H. (1979). J. Med. Chem. 22, 1-7.]).

[Scheme 1]

Experimental

Crystal data
  • C16H14ClN3O·CH2Cl2

  • Mr = 384.69

  • Triclinic, [P \overline 1]

  • a = 7.8310 (12) Å

  • b = 9.461 (2) Å

  • c = 12.6947 (5) Å

  • α = 94.284 (11)°

  • β = 93.821 (9)°

  • γ = 108.499 (13)°

  • V = 885.4 (2) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.53 mm−1

  • T = 173 K

  • 0.60 × 0.33 × 0.04 mm

Data collection
  • Bruker–Nonius KappaCCD diffractometer

  • Absorption correction: multi-scan SADABS (Sheldrick, 2003[Sheldrick, G. M. (2003). SADABS. University of Göttingen, Germany.]) Tmin = 0.763, Tmax = 0.979

  • 20348 measured reflections

  • 4040 independent reflections

  • 3124 reflections with I > 2σ(I)

  • Rint = 0.034

Refinement
  • R[F2 > 2σ(F2)] = 0.040

  • wR(F2) = 0.104

  • S = 1.03

  • 4040 reflections

  • 221 parameters

  • 1 restraint

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.76 e Å−3

  • Δρmin = −0.52 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N3—H3A⋯O1i 0.85 (2) 2.08 (2) 2.916 (2) 166 (2)
Symmetry code: (i) -x+1, -y+1, -z+2.

Data collection: COLLECT (Nonius, 1999[Nonius (1999). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: DIRAX (Duisenberg, 1992[Duisenberg, A. J. M. (1992). J. Appl. Cryst. 25, 92-96.]); data reduction: EVALCCD (Duisenberg et al., 2003[Duisenberg, A. J. M., Kroon-Batenburg, L. M. J. & Schreurs, A. M. M. (2003). J. Appl. Cryst. 36, 220-229.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: DIAMOND (Brandenburg, 2007[Brandenburg, K. (2007). DIAMOND. Crystal Impact GbR, Bonn, Germany.]).; software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Comment top

Chlordiazepozide (7-chloro-2-methylamino-5-phenyl-3H-1,4-benzodiazepine 4-oxide) was the first benzodiazepine to enter the market as member of a new class of powerful tranquilizers. The crystal structure of the hydrochloride was determined in 1979 (Herrnstadt et al., 1979), the structure of the pure compound in 1982 (Bertolasi et al., 1982). The reason for the study of chlordiazepoxide salts was the presence of three potential protonation sites (Herrnstadt et al. 1979). In order to study a number of different chlordiazepoxide salts, we synthesized the compound according to the description by Sternbach et al. (1961). The final step in this synthesis is the crystallization from dichloromethane. It turned out that the crystallization product that forms initially is a chlordiazepoxide dichloromethane solvate, whose structure is described here. The title compound (Fig. 1) features pairs of chlordiazepoxide molecules, which are hydrogen-bonded via two symmetry-equivalent N–H···O bonds across an inversion centre (Fig. 2). The same pattern could be found in the hydrochloride (Herrnstadt et al., 1979). In the structure of pure chlordiazepoxide, pairs of molecules of the same chirality (due to the high energy barrier of ring inversion, benzodiazepines are chiral) were observed and it was argued that this arrangement might be more stable than dimers of two different enantiomers. However, this effect must be quite subtle since the only interactions between the chlordiazepoxide and dichloromethane molecules are due to van der Waals forces. The dihedral angle between the two phenyl groups is 75.25 (6)°.

Related literature top

For the synthesis of chlordiazepoxide, see: Sternbach et al. (1961). For the structure of chlordiazepoxide, see: Bertolasi et al. (1982). For the structure of a second polymorph of chlordiazepoxide, see: Singh et al. (1998). For the structure of chlordiazepoxide hydrochloride, see: Herrnstadt et al. (1979). For the early history of benzopdiazepines, see: Sternbach (1979).

Experimental top

Chlordiazepoxide was synthesized according to the procedure described by Sternbach et al.(1961), starting from commercial 2-amino-5-chlorobenzophenone. Slow evaporation of the solution of the final product in dichloromethane yielded colourless, block-shaped crystals of the title compound. Once removed from the mother liquor, the crystals decomposed slowly (within days), yielding solvent-free chlordiazepoxide.

Refinement top

All H atoms except that attached to N were placed at calculated positions and refined riding. The N–H atom was located from the Fourier map and refined with the N–H distance restrained to 0.88 (2) Å.

Structure description top

Chlordiazepozide (7-chloro-2-methylamino-5-phenyl-3H-1,4-benzodiazepine 4-oxide) was the first benzodiazepine to enter the market as member of a new class of powerful tranquilizers. The crystal structure of the hydrochloride was determined in 1979 (Herrnstadt et al., 1979), the structure of the pure compound in 1982 (Bertolasi et al., 1982). The reason for the study of chlordiazepoxide salts was the presence of three potential protonation sites (Herrnstadt et al. 1979). In order to study a number of different chlordiazepoxide salts, we synthesized the compound according to the description by Sternbach et al. (1961). The final step in this synthesis is the crystallization from dichloromethane. It turned out that the crystallization product that forms initially is a chlordiazepoxide dichloromethane solvate, whose structure is described here. The title compound (Fig. 1) features pairs of chlordiazepoxide molecules, which are hydrogen-bonded via two symmetry-equivalent N–H···O bonds across an inversion centre (Fig. 2). The same pattern could be found in the hydrochloride (Herrnstadt et al., 1979). In the structure of pure chlordiazepoxide, pairs of molecules of the same chirality (due to the high energy barrier of ring inversion, benzodiazepines are chiral) were observed and it was argued that this arrangement might be more stable than dimers of two different enantiomers. However, this effect must be quite subtle since the only interactions between the chlordiazepoxide and dichloromethane molecules are due to van der Waals forces. The dihedral angle between the two phenyl groups is 75.25 (6)°.

For the synthesis of chlordiazepoxide, see: Sternbach et al. (1961). For the structure of chlordiazepoxide, see: Bertolasi et al. (1982). For the structure of a second polymorph of chlordiazepoxide, see: Singh et al. (1998). For the structure of chlordiazepoxide hydrochloride, see: Herrnstadt et al. (1979). For the early history of benzopdiazepines, see: Sternbach (1979).

Computing details top

Data collection: COLLECT (Nonius, 1999); cell refinement: DIRAX (Duisenberg, 1992); data reduction: EVALCCD (Duisenberg et al., 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2007).; software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. The centrosymmetric chlordiazepoxide dimers in the title compound. The half-transparent moiety is generated by (i)–x+1, –y+1, –z+2.
7-chloro-2-methylamino-5-phenyl-3H-1,4-benzodiazepine 4-oxide dichloromethane monosolvate top
Crystal data top
C16H14ClN3O·CH2Cl2Z = 2
Mr = 384.69F(000) = 396
Triclinic, P1Dx = 1.443 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.8310 (12) ÅCell parameters from 38 reflections
b = 9.461 (2) Åθ = 8.7–19.5°
c = 12.6947 (5) ŵ = 0.53 mm1
α = 94.284 (11)°T = 173 K
β = 93.821 (9)°Plate, colourless
γ = 108.499 (13)°0.60 × 0.33 × 0.04 mm
V = 885.4 (2) Å3
Data collection top
Bruker–Nonius KappaCCD
diffractometer
4040 independent reflections
Radiation source: fine-focus sealed tube3124 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.034
φ&ω scansθmax = 27.5°, θmin = 4.5°
Absorption correction: multi-scan
SADABS (Sheldrick, 2003)
h = 1010
Tmin = 0.763, Tmax = 0.979k = 1212
20348 measured reflectionsl = 1516
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.104 w = 1/[σ2(Fo2) + (0.0409P)2 + 0.7625P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max < 0.001
4040 reflectionsΔρmax = 0.76 e Å3
221 parametersΔρmin = 0.52 e Å3
1 restraint
Crystal data top
C16H14ClN3O·CH2Cl2γ = 108.499 (13)°
Mr = 384.69V = 885.4 (2) Å3
Triclinic, P1Z = 2
a = 7.8310 (12) ÅMo Kα radiation
b = 9.461 (2) ŵ = 0.53 mm1
c = 12.6947 (5) ÅT = 173 K
α = 94.284 (11)°0.60 × 0.33 × 0.04 mm
β = 93.821 (9)°
Data collection top
Bruker–Nonius KappaCCD
diffractometer
4040 independent reflections
Absorption correction: multi-scan
SADABS (Sheldrick, 2003)
3124 reflections with I > 2σ(I)
Tmin = 0.763, Tmax = 0.979Rint = 0.034
20348 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0401 restraint
wR(F2) = 0.104H atoms treated by a mixture of independent and constrained refinement
S = 1.03Δρmax = 0.76 e Å3
4040 reflectionsΔρmin = 0.52 e Å3
221 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > 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
xyzUiso*/Ueq
C10.4054 (3)0.0142 (2)0.68015 (14)0.0228 (4)
C20.4147 (3)0.1283 (2)0.67919 (15)0.0233 (4)
C30.3620 (3)0.2137 (2)0.76314 (15)0.0229 (4)
C40.3110 (2)0.1489 (2)0.85106 (14)0.0219 (4)
C50.3146 (2)0.00119 (19)0.85985 (14)0.0183 (3)
C60.3543 (2)0.08072 (19)0.76981 (14)0.0188 (4)
C70.3392 (2)0.23116 (19)0.76213 (14)0.0193 (4)
C80.2418 (3)0.2605 (2)0.66676 (14)0.0213 (4)
C90.3090 (3)0.3890 (2)0.61483 (15)0.0251 (4)
C100.2113 (3)0.4097 (2)0.52552 (16)0.0335 (5)
C110.0461 (3)0.3048 (3)0.48835 (17)0.0375 (5)
C120.0217 (3)0.1780 (3)0.53961 (18)0.0374 (5)
C130.0762 (3)0.1547 (2)0.62793 (16)0.0300 (4)
C140.4974 (2)0.2983 (2)0.93612 (13)0.0189 (4)
C150.3509 (2)0.1940 (2)0.99178 (13)0.0186 (4)
C160.1763 (3)0.1635 (2)1.14472 (17)0.0334 (5)
C170.0152 (4)0.5580 (3)0.1687 (3)0.0561 (7)
Cl10.50033 (8)0.20239 (6)0.57295 (4)0.03756 (16)
Cl20.04988 (9)0.72192 (8)0.10404 (6)0.0542 (2)
Cl30.19167 (10)0.57040 (9)0.26233 (6)0.0620 (2)
O10.39853 (18)0.47104 (13)0.84472 (10)0.0218 (3)
N10.4092 (2)0.33547 (16)0.84073 (11)0.0176 (3)
N20.2700 (2)0.05504 (17)0.95575 (12)0.0203 (3)
N30.3075 (2)0.25397 (18)1.08078 (12)0.0227 (3)
H10.43360.06790.61990.027*
H30.36130.31450.75990.027*
H40.27200.20760.90780.026*
H90.42140.46210.64070.030*
H100.25810.49630.48960.040*
H110.02060.32020.42750.045*
H120.13570.10660.51440.045*
H130.03030.06620.66210.036*
H14A0.56170.39060.98360.023*
H14B0.58620.24900.91590.023*
H16A0.06130.11561.10110.050*
H16B0.15780.22741.20430.050*
H16C0.22110.08631.17200.050*
H17A0.09800.53800.20380.067*
H17B0.00010.47230.11510.067*
H3A0.379 (3)0.3395 (19)1.1074 (17)0.027*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0312 (10)0.0182 (9)0.0194 (9)0.0079 (8)0.0027 (7)0.0051 (7)
C20.0296 (10)0.0209 (9)0.0205 (9)0.0104 (8)0.0026 (7)0.0002 (7)
C30.0275 (10)0.0175 (9)0.0247 (9)0.0094 (8)0.0012 (8)0.0030 (7)
C40.0233 (9)0.0206 (9)0.0214 (9)0.0059 (7)0.0006 (7)0.0067 (7)
C50.0156 (8)0.0184 (8)0.0192 (8)0.0037 (7)0.0011 (7)0.0015 (6)
C60.0206 (9)0.0148 (8)0.0200 (9)0.0049 (7)0.0020 (7)0.0013 (6)
C70.0209 (9)0.0169 (8)0.0197 (9)0.0055 (7)0.0009 (7)0.0028 (6)
C80.0288 (10)0.0192 (9)0.0178 (9)0.0117 (8)0.0014 (7)0.0008 (7)
C90.0343 (11)0.0206 (9)0.0209 (9)0.0100 (8)0.0001 (8)0.0017 (7)
C100.0522 (14)0.0285 (10)0.0247 (10)0.0199 (10)0.0009 (9)0.0070 (8)
C110.0535 (15)0.0380 (12)0.0262 (11)0.0260 (11)0.0128 (10)0.0004 (9)
C120.0385 (13)0.0344 (12)0.0349 (12)0.0114 (10)0.0164 (10)0.0044 (9)
C130.0361 (12)0.0227 (10)0.0292 (10)0.0087 (9)0.0062 (9)0.0024 (8)
C140.0175 (9)0.0201 (9)0.0175 (8)0.0044 (7)0.0028 (7)0.0023 (7)
C150.0166 (8)0.0221 (9)0.0165 (8)0.0058 (7)0.0015 (7)0.0038 (7)
C160.0309 (11)0.0362 (11)0.0273 (11)0.0018 (9)0.0105 (9)0.0007 (8)
C170.0338 (14)0.0492 (15)0.085 (2)0.0101 (12)0.0003 (13)0.0207 (14)
Cl10.0618 (4)0.0276 (3)0.0305 (3)0.0216 (2)0.0185 (2)0.00376 (19)
Cl20.0412 (3)0.0717 (5)0.0646 (4)0.0315 (3)0.0154 (3)0.0322 (3)
Cl30.0553 (4)0.0777 (5)0.0559 (4)0.0205 (4)0.0033 (3)0.0317 (4)
O10.0268 (7)0.0131 (6)0.0243 (7)0.0060 (5)0.0019 (5)0.0003 (5)
N10.0189 (7)0.0153 (7)0.0183 (7)0.0051 (6)0.0001 (6)0.0026 (5)
N20.0203 (8)0.0206 (8)0.0185 (7)0.0048 (6)0.0013 (6)0.0018 (6)
N30.0214 (8)0.0231 (8)0.0203 (8)0.0036 (7)0.0013 (6)0.0015 (6)
Geometric parameters (Å, º) top
C1—C21.372 (3)C16—N31.451 (3)
C1—C61.402 (2)C17—Cl31.730 (3)
C2—C31.391 (3)C17—Cl21.762 (3)
C2—Cl11.7428 (19)O1—N11.3090 (18)
C3—C41.376 (3)C1—H10.9500
C4—C51.407 (2)C3—H30.9500
C5—N21.393 (2)C4—H40.9500
C5—C61.413 (2)C9—H90.9500
C6—C71.475 (2)C10—H100.9500
C7—N11.306 (2)C11—H110.9500
C7—C81.478 (2)C12—H120.9500
C8—C131.394 (3)C13—H130.9500
C8—C91.396 (3)C14—H14A0.9900
C9—C101.386 (3)C14—H14B0.9900
C10—C111.384 (3)C16—H16A0.9800
C11—C121.380 (3)C16—H16B0.9800
C12—C131.387 (3)C16—H16C0.9800
C14—N11.474 (2)C17—H17A0.9900
C14—C151.511 (2)C17—H17B0.9900
C15—N21.297 (2)N3—H3A0.854 (16)
C15—N31.338 (2)
C2—C1—C6120.20 (16)C6—C1—H1119.9
C1—C2—C3121.22 (17)C4—C3—H3120.7
C1—C2—Cl1119.68 (14)C2—C3—H3120.7
C3—C2—Cl1119.07 (14)C3—C4—H4118.8
C4—C3—C2118.55 (16)C5—C4—H4118.8
C3—C4—C5122.33 (16)C10—C9—H9120.1
N2—C5—C4116.32 (15)C8—C9—H9120.1
N2—C5—C6126.13 (16)C11—C10—H10119.8
C4—C5—C6117.48 (16)C9—C10—H10119.8
C1—C6—C5119.75 (16)C12—C11—H11120.0
C1—C6—C7116.61 (15)C10—C11—H11120.0
C5—C6—C7123.60 (16)C11—C12—H12120.0
N1—C7—C6119.34 (16)C13—C12—H12120.0
N1—C7—C8121.14 (15)C12—C13—H13119.8
C6—C7—C8119.51 (15)C8—C13—H13119.8
C13—C8—C9119.24 (17)N1—C14—H14A110.2
C13—C8—C7118.08 (16)C15—C14—H14A110.2
C9—C8—C7122.68 (17)N1—C14—H14B110.2
C10—C9—C8119.88 (19)C15—C14—H14B110.2
C11—C10—C9120.4 (2)H14A—C14—H14B108.5
C12—C11—C10120.04 (19)N3—C16—H16A109.5
C11—C12—C13120.1 (2)N3—C16—H16B109.5
C12—C13—C8120.31 (19)H16A—C16—H16B109.5
N1—C14—C15107.42 (14)N3—C16—H16C109.5
N2—C15—N3121.51 (16)H16A—C16—H16C109.5
N2—C15—C14122.57 (16)H16B—C16—H16C109.5
N3—C15—C14115.91 (16)Cl3—C17—H17A109.0
Cl3—C17—Cl2112.88 (15)Cl2—C17—H17A109.0
C7—N1—O1124.88 (15)Cl3—C17—H17B109.0
C7—N1—C14118.94 (14)Cl2—C17—H17B109.0
O1—N1—C14116.05 (13)H17A—C17—H17B107.8
C15—N2—C5118.83 (15)C15—N3—H3A117.0 (15)
C15—N3—C16121.24 (16)C16—N3—H3A119.7 (15)
C2—C1—H1119.9
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3A···O1i0.85 (2)2.08 (2)2.916 (2)166 (2)
Symmetry code: (i) x+1, y+1, z+2.

Experimental details

Crystal data
Chemical formulaC16H14ClN3O·CH2Cl2
Mr384.69
Crystal system, space groupTriclinic, P1
Temperature (K)173
a, b, c (Å)7.8310 (12), 9.461 (2), 12.6947 (5)
α, β, γ (°)94.284 (11), 93.821 (9), 108.499 (13)
V3)885.4 (2)
Z2
Radiation typeMo Kα
µ (mm1)0.53
Crystal size (mm)0.60 × 0.33 × 0.04
Data collection
DiffractometerBruker–Nonius KappaCCD
Absorption correctionMulti-scan
SADABS (Sheldrick, 2003)
Tmin, Tmax0.763, 0.979
No. of measured, independent and
observed [I > 2σ(I)] reflections
20348, 4040, 3124
Rint0.034
(sin θ/λ)max1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.040, 0.104, 1.03
No. of reflections4040
No. of parameters221
No. of restraints1
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.76, 0.52

Computer programs: COLLECT (Nonius, 1999), DIRAX (Duisenberg, 1992), EVALCCD (Duisenberg et al., 2003), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2007)., publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3A···O1i0.854 (16)2.080 (17)2.916 (2)166 (2)
Symmetry code: (i) x+1, y+1, z+2.
 

Acknowledgements

The Swedish Research Council is acknowledged for providing funding for the single-crystal diffractometer.

References

First citationBertolasi, V., Sacerdoti, M., Gilli, G. & Borea, P. A. (1982). Acta Cryst. B38, 1768–1772.  CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
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