Dimethyl 6-iodo-2-methyl-1,2-di­hydro­quinoline-2,4-di­carboxyl­ate

Gültekin, Z.; Frey, W.; Hökelek, T.

doi:10.1107/S1600536813023544

organic compounds

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ISSN: 2056-9890

Volume 69| Part 9| September 2013| Page o1476

doi:10.1107/S1600536813023544

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Dimethyl 6-iodo-2-methyl-1,2-dihydroquinoline-2,4-dicarboxylate

Zeynep Gültekin,^a Wolfgang Frey ^b and Tuncer Hökelek ^c ^*

^aDepartment of Chemistry, Çankırı Karatekin University, TR-18100 Çankırı, Turkey, ^bUniversität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany, and ^cDepartment of Physics, Hacettepe University, 06800 Beytepe, Ankara, Turkey
^*Correspondence e-mail: merzifon@hacettepe.edu.tr

(Received 30 July 2013; accepted 21 August 2013; online 31 August 2013)

In the title compound, C₁₄H₁₄INO₄, the dihydropyridine ring adopts a twist conformation. In the crystal, pairs of N—H⋯O and C—H⋯O hydrogen bonds link the molecules into inversion R₂²(10) and R₂²(18) dimers, forming infinite double chains running along the c axis.

Related literature

For the conversion of 1,2-dihydroquinoline derivatives to the syntheses of quinolines, see: Dauphinee & Forrest (1978 ). For the conversion of 1,2-dihydroquinoline derivatives to the syntheses of 1,2,3,4-tetrahydroquinolines, see: Katritzky et al. (1996 ). For literature methods for the preparation of 1,2-dihydroquinolines, see: Dauphinee & Forrest (1978); Durgadas et al. (2010 ); Gültekin & Frey (2012 ); Makino et al. (2003 ); Yadav et al. (2007 ); Waldmann et al. (2008 ). For related structures, see: Gültekin et al. (2010 , 2011a ,b , 2012a ,b ). For ring puckering parameters, see: Cremer & Pople (1975 ). For hydrogen-bond motifs, see: Bernstein et al. (1995 ).

Experimental

Crystal data

C₁₄H₁₄INO₄
M_r = 387.16
Triclinic, $[P \overline 1]$
a = 7.7994 (14) Å
b = 10.2797 (8) Å
c = 10.8056 (8) Å
α = 116.862 (3)°
β = 103.956 (4)°
γ = 96.780 (4)°
V = 723.80 (16) Å³
Z = 2
Mo Kα radiation
μ = 2.22 mm⁻¹
T = 100 K
0.76 × 0.65 × 0.48 mm

Data collection

Bruker Kappa APEXII DUO diffractometer
Absorption correction: numerical (Blessing, 1995 ) T_min = 0.283, T_max = 0.415
43287 measured reflections
7044 independent reflections
6902 reflections with I > 2σ(I)
R_int = 0.032

Refinement

R[F² > 2σ(F²)] = 0.027
wR(F²) = 0.073
S = 1.24
7044 reflections
190 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 1.88 e Å⁻³
Δρ_min = −1.54 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O3ⁱ	0.82 (2)	2.17 (2)	2.9795 (19)	169 (2)
C5—H5⋯O1	0.95	2.22	2.866 (2)	125
C12—H12C⋯O1ⁱⁱ	0.98	2.46	3.132 (2)	126
Symmetry codes: (i) -x+1, -y+2, -z+2; (ii) -x+1, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2008 ); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; 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, 2012 ); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536813023544/gw2137sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536813023544/gw2137Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536813023544/gw2137Isup3.cml

checkCIF report

Comment top

1,2-Dihydroquinoline derivatives are important for the preparation of pharmaceuticals and other biologically active compounds, and they are versatile intermediates in organic chemistry. They are converted to the syntheses of quinolines (Dauphinee & Forrest, 1978) and 1,2,3,4-tetrahydroquinolines (Katritzky et al., 1996). Several methods have been described for the syntheses of 1,2-dihydroquinolines (Durgadas et al., 2010; Makino et al., 2003; Yadav et al., 2007; Dauphinee & Forrest, 1978; Waldmann et al., 2008).

The structures of some 1,2-dihydroquinoline derivatives, C₁₆H₁₉NO₄ (Gültekin et al., 2010), C₁₄H₁₅NO₄ (Gültekin et al., 2011a), C₁₇H₂₁NO₇ (Gültekin et al., 2011b), C₁₆H₁₇NO₅ (Gültekin et al., 2012a) and C₁₄H₁₄BrNO₄ (Gültekin et al., 2012b) have also been determined.

In the title compound (Fig. 1), the ring A (C1-C4/C9/C10/N1) is not planar, but adopting a twisted conformation with puckering parameters (Cremer & Pople, 1975) Q_T = 0.332 (1)Å, ϕ = 35.3 (3)° and θ = 66.0 (2)°. Ring A has a pseudo two-fold axis running through the midpoints of the N1—C1 and C3—C4 bonds.

In the crystal structure, intermolecular N—H···O and C—H···O hydrogen bonds (Table 1) link the molecules into centrosymmetric R₂²(10) and R₂²(18) dimers, respectively (Bernstein et al., 1995) (Fig. 2), to form infinite double chains running along the c-axis.

Related literature top

For the conversion of 1,2-dihydroquinoline derivatives to the syntheses of quinolines, see: Dauphinee & Forrest (1978). For the conversion of 1,2-dihydroquinoline derivatives to the syntheses of 1,2,3,4-tetrahydroquinolines, see: Katritzky et al. (1996). For literature methods for the preparation of 1,2-dihydroquinolines, see: Dauphinee & Forrest (1978); Durgadas et al. (2010); Gültekin & Frey (2012); Makino et al. (2003); Yadav et al. (2007); Waldmann et al. (2008). For related structures, see: Gültekin et al. (2010, 2011a,b, 2012a,b) For ring puckering parameters, see: Cremer & Pople (1975). For hydrogen-bond motifs, see: Bernstein et al. (1995).

Experimental top

The title compound was synthesized by the literature method (Gültekin & Frey, 2012; Waldmann et al., 2008). p-iodo aniline (100 mg, 1 eq) was dissolved in acetonitrile (1.5 ml), and then Bi(OTf)₃ (5 mol%, 0.05 eq) and methyl pyruvate (2.2 eq) were added to the mixture. The mixture was heated by microwave irradiation for 7 h until the starting material was completely consumed as monitored by TLC. The resultant residue was directly purified by flash chromatography on silica (EtOAc:Cylohexane 1:2). Recrystallization over pentane and ethyl acetate (70:30) gave a yellow crystalline solid (yield: 34%), R_f 0.56 (2:1 Cyclohexane/EtOAc) m.p.: 393 K.

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); 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, 2012); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009).

Figures top

	Fig. 1. The molecular structure of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bond is shown as dashed line.
	Fig. 2. A partial packing diagram. Hydrogen bonds are shown as dashed lines. Hydrogen atoms not involved in hydrogen bonding have been omitted for clarity.

Dimethyl 6-iodo-2-methyl-1,2-dihydroquinoline-2,4-dicarboxylate top

Crystal data top

C₁₄H₁₄INO₄	Z = 2
M_r = 387.16	F(000) = 380
Triclinic, P1	D_x = 1.776 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.7994 (14) Å	Cell parameters from 6892 reflections
b = 10.2797 (8) Å	θ = 2.3–36.5°
c = 10.8056 (8) Å	µ = 2.22 mm⁻¹
α = 116.862 (3)°	T = 100 K
β = 103.956 (4)°	Block, yellow
γ = 96.780 (4)°	0.76 × 0.65 × 0.48 mm
V = 723.80 (16) Å³

Data collection top

Bruker Kappa APEXII DUO diffractometer	7044 independent reflections
Radiation source: fine-focus sealed tube	6902 reflections with I > 2σ(I)
Triumph monochromator	R_int = 0.032
ϕ and ω scans	θ_max = 36.5°, θ_min = 2.3°
Absorption correction: numerical (Blessing, 1995)	h = −13→13
T_min = 0.283, T_max = 0.415	k = −17→17
43287 measured reflections	l = −18→18

Refinement top

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)] = 0.027	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.073	w = 1/[σ²(F_o²) + (0.0263P)² + 0.7072P] where P = (F_o² + 2F_c²)/3
S = 1.24	(Δ/σ)_max < 0.001
7044 reflections	Δρ_max = 1.88 e Å⁻³
190 parameters	Δρ_min = −1.54 e Å⁻³
1 restraint	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0715 (18)

Crystal data top

C₁₄H₁₄INO₄	γ = 96.780 (4)°
M_r = 387.16	V = 723.80 (16) Å³
Triclinic, P1	Z = 2
a = 7.7994 (14) Å	Mo Kα radiation
b = 10.2797 (8) Å	µ = 2.22 mm⁻¹
c = 10.8056 (8) Å	T = 100 K
α = 116.862 (3)°	0.76 × 0.65 × 0.48 mm
β = 103.956 (4)°

Data collection top

Bruker Kappa APEXII DUO diffractometer	7044 independent reflections
Absorption correction: numerical (Blessing, 1995)	6902 reflections with I > 2σ(I)
T_min = 0.283, T_max = 0.415	R_int = 0.032
43287 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.027	1 restraint
wR(F²) = 0.073	H atoms treated by a mixture of independent and constrained refinement
S = 1.24	Δρ_max = 1.88 e Å⁻³
7044 reflections	Δρ_min = −1.54 e Å⁻³
190 parameters

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
I1	0.017285 (15)	0.670510 (12)	0.215800 (11)	0.02370 (4)
O1	0.28824 (19)	0.31504 (13)	0.37768 (13)	0.0217 (2)
O2	0.34912 (17)	0.25624 (12)	0.55598 (13)	0.01879 (18)
O3	0.69165 (15)	0.92071 (11)	0.93569 (13)	0.01678 (17)
O4	0.78140 (13)	0.71616 (12)	0.92154 (12)	0.01509 (16)
N1	0.32777 (15)	0.77436 (13)	0.85280 (12)	0.01270 (17)
H1	0.335 (4)	0.858 (2)	0.920 (2)	0.020 (6)*
C1	0.46679 (16)	0.70426 (14)	0.88944 (13)	0.01127 (17)
C2	0.42693 (16)	0.54604 (14)	0.76450 (14)	0.01201 (18)
H2	0.472 (3)	0.475 (3)	0.787 (3)	0.013 (5)*
C3	0.33684 (16)	0.50661 (14)	0.62481 (14)	0.01130 (17)
C4	0.26466 (16)	0.61703 (14)	0.59074 (14)	0.01143 (17)
C5	0.19306 (18)	0.59520 (15)	0.44880 (15)	0.01460 (19)
H5	0.1942	0.5060	0.3664	0.018*
C6	0.12035 (19)	0.70379 (16)	0.42832 (15)	0.0157 (2)
C7	0.11561 (19)	0.83472 (16)	0.54662 (16)	0.0165 (2)
H7	0.0636	0.9073	0.5310	0.020*
C8	0.18759 (18)	0.85846 (15)	0.68790 (15)	0.0149 (2)
H8	0.1851	0.9481	0.7693	0.018*
C9	0.26382 (16)	0.75191 (14)	0.71195 (14)	0.01145 (17)
C10	0.47035 (19)	0.70673 (18)	1.03339 (15)	0.0169 (2)
H10A	0.4966	0.8115	1.1121	0.025*
H10B	0.5656	0.6607	1.0599	0.025*
H10C	0.3511	0.6496	1.0199	0.025*
C11	0.65818 (16)	0.79393 (14)	0.91643 (13)	0.01153 (17)
C12	0.96471 (18)	0.78904 (19)	0.94143 (18)	0.0191 (2)
H12A	1.0454	0.7234	0.9438	0.029*
H12B	1.0110	0.8854	1.0343	0.029*
H12C	0.9615	0.8076	0.8597	0.029*
C13	0.31983 (17)	0.35216 (14)	0.50561 (15)	0.01327 (19)
C14	0.3488 (3)	0.10914 (18)	0.4461 (2)	0.0252 (3)
H14A	0.3710	0.0458	0.4910	0.038*
H14B	0.4454	0.1193	0.4050	0.038*
H14C	0.2297	0.0621	0.3674	0.038*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
I1	0.02815 (6)	0.02630 (6)	0.01695 (5)	0.00288 (4)	0.00133 (4)	0.01504 (4)
O1	0.0310 (6)	0.0176 (4)	0.0144 (4)	0.0086 (4)	0.0071 (4)	0.0059 (4)
O2	0.0239 (5)	0.0128 (4)	0.0208 (5)	0.0062 (3)	0.0069 (4)	0.0093 (4)
O3	0.0174 (4)	0.0108 (4)	0.0201 (4)	0.0024 (3)	0.0085 (3)	0.0053 (3)
O4	0.0096 (3)	0.0185 (4)	0.0204 (4)	0.0040 (3)	0.0045 (3)	0.0124 (4)
N1	0.0118 (4)	0.0151 (4)	0.0112 (4)	0.0057 (3)	0.0040 (3)	0.0060 (3)
C1	0.0095 (4)	0.0137 (4)	0.0106 (4)	0.0023 (3)	0.0028 (3)	0.0065 (4)
C2	0.0111 (4)	0.0128 (4)	0.0128 (4)	0.0024 (3)	0.0030 (3)	0.0076 (4)
C3	0.0104 (4)	0.0116 (4)	0.0119 (4)	0.0021 (3)	0.0031 (3)	0.0063 (4)
C4	0.0106 (4)	0.0121 (4)	0.0117 (4)	0.0024 (3)	0.0028 (3)	0.0066 (4)
C5	0.0158 (5)	0.0150 (5)	0.0125 (5)	0.0025 (4)	0.0028 (4)	0.0078 (4)
C6	0.0162 (5)	0.0177 (5)	0.0149 (5)	0.0033 (4)	0.0025 (4)	0.0109 (4)
C7	0.0163 (5)	0.0184 (5)	0.0186 (5)	0.0068 (4)	0.0048 (4)	0.0123 (5)
C8	0.0149 (5)	0.0159 (5)	0.0163 (5)	0.0071 (4)	0.0056 (4)	0.0090 (4)
C9	0.0097 (4)	0.0134 (4)	0.0119 (4)	0.0033 (3)	0.0036 (3)	0.0068 (4)
C10	0.0163 (5)	0.0237 (6)	0.0134 (5)	0.0042 (4)	0.0055 (4)	0.0114 (5)
C11	0.0108 (4)	0.0129 (4)	0.0098 (4)	0.0025 (3)	0.0035 (3)	0.0049 (4)
C12	0.0099 (4)	0.0269 (6)	0.0230 (6)	0.0032 (4)	0.0048 (4)	0.0149 (5)
C13	0.0123 (4)	0.0122 (4)	0.0143 (5)	0.0025 (3)	0.0039 (4)	0.0062 (4)
C14	0.0297 (7)	0.0140 (5)	0.0318 (8)	0.0092 (5)	0.0120 (6)	0.0095 (5)

Geometric parameters (Å, º) top

I1—C6	2.0908 (14)	C4—C9	1.4154 (17)
N1—C1	1.4447 (17)	C5—C6	1.3888 (19)
N1—C9	1.3812 (17)	C5—H5	0.9500
N1—H1	0.821 (17)	C6—C7	1.388 (2)
O1—C13	1.2059 (17)	C7—C8	1.387 (2)
O2—C13	1.3412 (17)	C7—H7	0.9500
O2—C14	1.439 (2)	C8—C9	1.3989 (18)
O3—C11	1.2075 (16)	C8—H8	0.9500
O4—C11	1.3273 (16)	C10—H10A	0.9800
O4—C12	1.4508 (17)	C10—H10B	0.9800
C1—C2	1.5028 (18)	C10—H10C	0.9800
C1—C10	1.5376 (18)	C12—H12A	0.9800
C1—C11	1.5444 (17)	C12—H12B	0.9800
C2—C3	1.3435 (18)	C12—H12C	0.9800
C2—H2	0.94 (2)	C14—H14A	0.9800
C3—C4	1.4728 (17)	C14—H14B	0.9800
C3—C13	1.4890 (18)	C14—H14C	0.9800
C4—C5	1.4002 (18)

C13—O2—C14	114.26 (13)	C7—C8—H8	119.6
C11—O4—C12	115.43 (11)	C9—C8—H8	119.6
C1—N1—H1	115 (2)	N1—C9—C4	120.20 (11)
C9—N1—C1	120.03 (10)	N1—C9—C8	119.93 (11)
C9—N1—H1	116 (2)	C8—C9—C4	119.75 (11)
N1—C1—C2	109.26 (10)	C1—C10—H10A	109.5
N1—C1—C10	108.89 (10)	C1—C10—H10B	109.5
N1—C1—C11	110.73 (10)	C1—C10—H10C	109.5
C2—C1—C10	111.83 (11)	H10A—C10—H10B	109.5
C2—C1—C11	108.91 (10)	H10A—C10—H10C	109.5
C10—C1—C11	107.20 (10)	H10B—C10—H10C	109.5
C1—C2—H2	117.7 (15)	O3—C11—O4	124.68 (12)
C3—C2—C1	121.91 (11)	O3—C11—C1	123.96 (11)
C3—C2—H2	120.4 (15)	O4—C11—C1	111.31 (11)
C2—C3—C4	120.28 (11)	O4—C12—H12A	109.5
C2—C3—C13	118.60 (11)	O4—C12—H12B	109.5
C4—C3—C13	121.05 (11)	O4—C12—H12C	109.5
C5—C4—C3	124.75 (11)	H12A—C12—H12B	109.5
C5—C4—C9	118.89 (11)	H12A—C12—H12C	109.5
C9—C4—C3	116.33 (11)	H12B—C12—H12C	109.5
C4—C5—H5	119.9	O1—C13—O2	122.31 (13)
C6—C5—C4	120.11 (12)	O1—C13—C3	125.09 (12)
C6—C5—H5	119.9	O2—C13—C3	112.57 (11)
C5—C6—I1	119.55 (10)	O2—C14—H14A	109.5
C7—C6—I1	119.26 (10)	O2—C14—H14B	109.5
C7—C6—C5	121.19 (12)	O2—C14—H14C	109.5
C6—C7—H7	120.3	H14A—C14—H14B	109.5
C8—C7—C6	119.31 (12)	H14A—C14—H14C	109.5
C8—C7—H7	120.3	H14B—C14—H14C	109.5
C7—C8—C9	120.73 (12)

C14—O2—C13—O1	3.0 (2)	C2—C3—C4—C9	−11.93 (17)
C14—O2—C13—C3	−175.15 (12)	C13—C3—C4—C5	−6.82 (18)
C12—O4—C11—O3	−4.60 (19)	C13—C3—C4—C9	171.05 (11)
C12—O4—C11—C1	177.95 (11)	C2—C3—C13—O1	−159.19 (14)
C9—N1—C1—C2	−40.61 (15)	C2—C3—C13—O2	18.92 (16)
C9—N1—C1—C10	−163.02 (11)	C4—C3—C13—O1	17.9 (2)
C9—N1—C1—C11	79.35 (14)	C4—C3—C13—O2	−164.00 (11)
C1—N1—C9—C4	28.53 (17)	C3—C4—C5—C6	176.90 (12)
C1—N1—C9—C8	−155.41 (12)	C9—C4—C5—C6	−0.92 (19)
N1—C1—C2—C3	28.17 (16)	C3—C4—C9—N1	−0.21 (17)
C10—C1—C2—C3	148.81 (12)	C3—C4—C9—C8	−176.28 (11)
C11—C1—C2—C3	−92.90 (14)	C5—C4—C9—N1	177.79 (11)
N1—C1—C11—O3	14.82 (17)	C5—C4—C9—C8	1.72 (18)
N1—C1—C11—O4	−167.70 (10)	C4—C5—C6—I1	179.18 (9)
C2—C1—C11—O3	134.99 (13)	C4—C5—C6—C7	−0.5 (2)
C2—C1—C11—O4	−47.53 (14)	I1—C6—C7—C8	−178.59 (10)
C10—C1—C11—O3	−103.84 (15)	C5—C6—C7—C8	1.1 (2)
C10—C1—C11—O4	73.64 (13)	C6—C7—C8—C9	−0.2 (2)
C1—C2—C3—C4	−3.42 (18)	C7—C8—C9—N1	−177.23 (12)
C1—C2—C3—C13	173.68 (11)	C7—C8—C9—C4	−1.15 (19)
C2—C3—C4—C5	170.20 (12)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O3ⁱ	0.82 (2)	2.17 (2)	2.9795 (19)	169 (2)
C5—H5···O1	0.95	2.22	2.866 (2)	125
C12—H12C···O1ⁱⁱ	0.98	2.46	3.132 (2)	126

Symmetry codes: (i) −x+1, −y+2, −z+2; (ii) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O3ⁱ	0.82 (2)	2.17 (2)	2.9795 (19)	169 (2)
C5—H5···O1	0.95	2.22	2.866 (2)	125
C12—H12C···O1ⁱⁱ	0.98	2.46	3.132 (2)	126

Symmetry codes: (i) −x+1, −y+2, −z+2; (ii) −x+1, −y+1, −z+1.

Acknowledgements

The title compound was synthesized at RWTH Aachen University, Germany. The authors thank Professor Magnus Rueping of RWTH Aachen University for helpful discussions.

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