Ethyl 5-methyl-7-phenyl-1,2,4-triazolo[4,3-a]pyrimidine-6-carboxyl­ate

AboulWafa, O.M.; Farghaly, A.M.; Teleb, M.; Sinoussy, K.S.

doi:10.1107/S1600536814010113

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 70| Part 6| June 2014| Pages o672-o673

doi:10.1107/S1600536814010113

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access

Ethyl 5-methyl-7-phenyl-1,2,4-triazolo[4,3-a]pyrimidine-6-carboxylate

Omaima M. AboulWafa,^a ^* Ahmed M. Farghaly,^a Mohamed Teleb ^a and Khaled S. Sinoussy ^b

^aDepartment of Pharmaceutical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria 21521, Egypt, and ^bNational Institute of Oceanography and Fisheries, Alexandria University, Alexandria 21556, Egypt
^*Correspondence e-mail: omaimawafa@yahoo.com

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 8 April 2014; accepted 5 May 2014; online 17 May 2014)

In the title compound, C₁₅H₁₄N₄O₂, the triazolopyrimidine ring system is almost planar (r.m.s. deviation = 0.02 Å) and the phenyl ring is inclined to its mean plane by 42.45 (9)°. The carboxyl group is inclined to the triazolopyrimidine ring mean plane by 57.8 (3)°. In the molecule, there is a short C—H⋯O contact involving the carbonyl O atom and an H atom of the adjacent methyl substituent. In the crystal, neighbouring molecules are linked by C—H⋯O hydrogen bonds, forming chains propagating along [010]. There are also weak π–π interactions present involving the pyridine and phenyl rings of neighbouring chains [intercentroid distance = 3.8580 (16) Å].

CCDC reference: 1000732

Related literature

For information on annelated pyrimidine derivatives as promising vasodilating agents, see: Jeanneau-Nicolle et al. (1992 ); Ali et al. (2011 ). For details concerning triazolopyrimidines having antihypertensive and diuretic activity, see: Ali et al. (2011). For details of Biginelli dihydropyrimidine calcium channel blockers, see: Rovnyak et al. (1995 ); Triggle & Padmanabhan (1995 ); Ohno et al. (2002 ). For potential ex vivo calcium-channel-blocking activity, see: Farghaly et al. (2013 ).

Experimental

Crystal data

C₁₅H₁₄N₄O₂
M_r = 282.30
Monoclinic, P 2₁ /n
a = 10.322 (2) Å
b = 8.1678 (19) Å
c = 16.798 (4) Å
β = 92.111 (4)°
V = 1415.2 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 293 K
0.30 × 0.10 × 0.10 mm

Data collection

Rigaku SCXmini diffractometer
Absorption correction: multi-scan (REQAB; Jacobson, 1998 ) T_min = 0.610, T_max = 0.991
12066 measured reflections
2550 independent reflections
1742 reflections with I > 2σ(I)
R_int = 0.092

Refinement

R[F² > 2σ(F²)] = 0.076
wR(F²) = 0.182
S = 1.07
2550 reflections
193 parameters
H-atom parameters constrained
Δρ_max = 0.46 e Å⁻³
Δρ_min = −0.51 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C9—H9B⋯O2	0.96	2.58	3.127 (4)	116
C15—H15⋯O2ⁱ	0.93	2.57	3.246 (3)	129
Symmetry code: (i) x, y-1, z.

Data collection: PROCESS-AUTO (Rigaku, 1998 ); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku Americas and Rigaku, 2007 ); program(s) used to solve structure: SIR88 (Burla et al., 1989 ); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008 ); molecular graphics: PLATON (Spek, 2009 ) and CrystalStructure (Rigaku Americas and Rigaku, 2007); software used to prepare material for publication: SHELXL2013 and CrystalStructure.

Supporting information

CCDC reference: 1000732

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536814010113/su2724sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536814010113/su2724Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536814010113/su2724Isup3.cml

checkCIF report

Introduction top

Annelated pyrimidine derivatives have gained considerable interest as promising vasodilating agents (Jeanneau-Nicolle et al., 1992; Ali et al., 2011). Triazolopyrimidines in particular have shown antihypertensive as well as diuretic activities (Ali et al., 2011). The title compound has a triazolopyrimidine nucleus and was derivatized from the well known Biginelli dihydropyrimidine calcium channel blockers (Rovnyak et al., 1995; Triggle & Padmanabhan, 1995; Ohno et al., 2002). It has been shown to possess potential ex vivo calcium channel blocking activity (Farghaly et al., 2013). In the present investigation, the crystal structure of the title compound was obtained in an effort to gain information pertaining to the role of regiocontrol in the cyclization step as well as electronic induction in the conformation of such a molecule.

Discussion top

The stereochemistry of the title compound, Fig. 1, revealed that the product has retained its original stereochemistry, and that cyclization has occurred on N¹ as predicted from HMBC (Heteronuclear Multiple Bond Correlation experiment). A close contact between the ester moiety and the phenyl group is also evident.

In the title compound, the triazolopyrimidine ring system is planar [r.m.s. deviation 0.02 Å] and its mean plane is inclined to the phenyl ring (C10—C15) by 42.45 (9) °. The carboxyl group (COO) is inclined to the triazolopyrimidine ring mean plane by 57.8 (3) °. It occupies a cis position relative to C5═C6 double bond of the triazolopyrimidine ring system thus allowing potential stabilization of such a conformation. There is a short C—H···O contact involving atom O2 and an H atom of the adjacent methyl substituent (C9), see Table 1. The ester group is again oriented away from the phenyl ring substituent for steric considerations with a torsional angle C4—C5—C6—O1 = -56.1 (3)°.

In the crystal, neighbouring molecules are linked by C—H···O hydrogen bonds forming chains propagating along [010]; Table 1 and Fig. 2. There are also weak π-π interactions present involving the pyridine and phenyl rings of neighbouring chains [Cg2—Cg3ⁱ = 3.8580 (16) Å; Cg2 and Cg3 are the centroids of rings N1/N2/C2—C5 and C10—C15, respectively; symmetry code: (i) -x+3/2, y+1/2, -z+1/2].

Experimental top

Synthesis and crystallization top

A solution of ethyl 2-hydrazino-6-methyl-4-phenylpyrimidine-5-carboxylate (0.27 g, 1 mmole) in formic acid (5 ml) was heated under reflux for 27 h. The reaction mixture was concentrated to a small volume and diluted with ice-cold water. The precipitate was filtered, washed with water and dried. Colourless crystals of the title compound were obtained by slow evaporation of a solution in aqueous ethanol.

Refinement top

The H atoms were included in calculated positions and treated as riding atoms: C—H = 0.93 - 0.98 Å with U_iso(H) = 1.5U_eq(C-methyl) and = 1.2U_eq(C) for other H atoms.

Related literature top

For information on annelated pyrimidine derivatives as promising vasodilating agents, see: Jeanneau-Nicolle et al. (1992); Ali et al. (2011). For details concerning triazolopyrimidines having antihypertensive and diuretic activity, see: Ali et al. (2011). For details of Biginelli dihydropyrimidine calcium channel blockers, see: Rovnyak et al. (1995); Triggle & Padmanabhan (1995); Ohno et al. (2002). For potential ex vivo calcium-channel-blocking activity, see: Farghaly et al. (2013).

Computing details top

Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO (Rigaku, 1998); data reduction: CrystalStructure (Rigaku Americas and Rigaku, 2007); program(s) used to solve structure: SIR88 (Burla et al., 1989); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009) and CrystalStructure (Rigaku Americas and Rigaku, 2007); software used to prepare material for publication: SHELXL2013 (Sheldrick, 2008) and CrystalStructure (Rigaku Americas and Rigaku, 2007).

Figures top

	Fig. 1. A view of the molecular structure of the title molecule, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level. The intramolecular C—H···O hydrogen bond is shown as a dashed line (see Table 1 for details).
	Fig. 2. A view along the a axis of the crystal packing of the title compound. The C—H···O hydrogen bonds are shown as a dashed line (see Table 1 for details).

Ethyl 5-methyl-7-phenyl-1,2,4-triazolo[4,3-a]pyrimidine-6-carboxylate top

Crystal data top

C₁₅H₁₄N₄O₂	F(000) = 592
M_r = 282.30	D_x = 1.325 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71075 Å
a = 10.322 (2) Å	Cell parameters from 10163 reflections
b = 8.1678 (19) Å	θ = 3.1–27.6°
c = 16.798 (4) Å	µ = 0.09 mm⁻¹
β = 92.111 (4)°	T = 293 K
V = 1415.2 (5) Å³	Prism, colourless
Z = 4	0.30 × 0.10 × 0.10 mm

Data collection top

Rigaku SCXmini diffractometer	1742 reflections with I > 2σ(I)
ω scans	R_int = 0.092
Absorption correction: multi-scan (REQAB; Jacobson, 1998)	θ_max = 25.3°, θ_min = 3.2°
T_min = 0.610, T_max = 0.991	h = −12→12
12066 measured reflections	k = −9→9
2550 independent reflections	l = −20→20

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.076	w = 1/[σ²(F_o²) + (0.1047P)²] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.182	(Δ/σ)_max < 0.001
S = 1.07	Δρ_max = 0.46 e Å⁻³
2550 reflections	Δρ_min = −0.51 e Å⁻³
193 parameters	Extinction correction: SHELXL2013 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.118 (11)

Crystal data top

C₁₅H₁₄N₄O₂	V = 1415.2 (5) Å³
M_r = 282.30	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 10.322 (2) Å	µ = 0.09 mm⁻¹
b = 8.1678 (19) Å	T = 293 K
c = 16.798 (4) Å	0.30 × 0.10 × 0.10 mm
β = 92.111 (4)°

Data collection top

Rigaku SCXmini diffractometer	2550 independent reflections
Absorption correction: multi-scan (REQAB; Jacobson, 1998)	1742 reflections with I > 2σ(I)
T_min = 0.610, T_max = 0.991	R_int = 0.092
12066 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.076	0 restraints
wR(F²) = 0.182	H-atom parameters constrained
S = 1.07	Δρ_max = 0.46 e Å⁻³
2550 reflections	Δρ_min = −0.51 e Å⁻³
193 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.

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

	x	y	z	U_iso*/U_eq
O1	0.39205 (15)	0.6185 (2)	0.24879 (9)	0.0632 (5)
O2	0.51731 (19)	0.8413 (2)	0.24434 (12)	0.0817 (6)
N1	0.68299 (18)	0.3481 (2)	0.14373 (12)	0.0619 (6)
N2	0.65225 (18)	0.5557 (3)	0.04523 (11)	0.0602 (6)
N3	0.7530 (2)	0.3301 (3)	0.00856 (15)	0.0811 (7)
N4	0.6793 (2)	0.5809 (3)	−0.03304 (12)	0.0763 (7)
C1	0.7390 (3)	0.4421 (4)	−0.04963 (18)	0.0844 (9)
H1A	0.7702	0.4229	−0.1000	0.101*
C2	0.5898 (2)	0.6607 (3)	0.09427 (14)	0.0571 (6)
C3	0.6971 (2)	0.4037 (3)	0.06930 (15)	0.0631 (7)
C4	0.6228 (2)	0.4455 (3)	0.19354 (13)	0.0514 (6)
C5	0.5725 (2)	0.6021 (3)	0.16969 (13)	0.0512 (6)
C6	0.4935 (2)	0.7029 (3)	0.22516 (14)	0.0557 (6)
C7	0.3199 (3)	0.6916 (4)	0.31288 (18)	0.0855 (9)
H7A	0.3792	0.7412	0.3520	0.103*
H7B	0.2621	0.7759	0.2917	0.103*
C8	0.2453 (3)	0.5624 (4)	0.3499 (2)	0.1047 (11)
H8A	0.1806	0.5220	0.3123	0.157*
H8B	0.2040	0.6054	0.3957	0.157*
H8C	0.3023	0.4746	0.3660	0.157*
C9	0.5465 (3)	0.8207 (3)	0.06000 (17)	0.0752 (8)
H9A	0.6189	0.8944	0.0591	0.113*
H9B	0.4806	0.8665	0.0921	0.113*
H9C	0.5122	0.8044	0.0067	0.113*
C10	0.6102 (2)	0.3845 (3)	0.27599 (13)	0.0518 (6)
C11	0.6315 (2)	0.4852 (3)	0.34188 (15)	0.0604 (7)
H11	0.6588	0.5925	0.3347	0.073*
C12	0.6127 (2)	0.4282 (3)	0.41738 (16)	0.0716 (8)
H12	0.6269	0.4969	0.4609	0.086*
C13	0.5726 (3)	0.2680 (4)	0.42890 (17)	0.0764 (8)
H13	0.5570	0.2304	0.4799	0.092*
C14	0.5560 (2)	0.1660 (3)	0.36494 (18)	0.0735 (8)
H14	0.5313	0.0579	0.3728	0.088*
C15	0.5757 (2)	0.2217 (3)	0.28853 (15)	0.0594 (7)
H15	0.5659	0.1505	0.2455	0.071*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0658 (10)	0.0599 (10)	0.0652 (11)	−0.0005 (8)	0.0222 (8)	−0.0063 (8)
O2	0.0989 (14)	0.0453 (11)	0.1024 (15)	0.0022 (9)	0.0206 (11)	−0.0087 (9)
N1	0.0677 (12)	0.0523 (12)	0.0665 (14)	0.0044 (10)	0.0151 (10)	−0.0045 (10)
N2	0.0599 (12)	0.0686 (14)	0.0527 (12)	−0.0042 (10)	0.0113 (9)	0.0021 (10)
N3	0.0879 (16)	0.0836 (17)	0.0737 (16)	−0.0003 (13)	0.0294 (12)	−0.0176 (13)
N4	0.0772 (14)	0.0967 (18)	0.0560 (14)	−0.0106 (13)	0.0176 (11)	0.0007 (13)
C1	0.088 (2)	0.100 (2)	0.0668 (19)	−0.0110 (18)	0.0246 (15)	−0.0165 (18)
C2	0.0522 (13)	0.0566 (15)	0.0629 (16)	−0.0033 (11)	0.0078 (11)	0.0020 (12)
C3	0.0631 (15)	0.0613 (16)	0.0658 (17)	−0.0007 (12)	0.0139 (12)	−0.0080 (13)
C4	0.0514 (12)	0.0438 (13)	0.0594 (15)	−0.0020 (10)	0.0069 (10)	−0.0040 (11)
C5	0.0534 (13)	0.0459 (13)	0.0549 (14)	−0.0033 (10)	0.0091 (10)	0.0008 (10)
C6	0.0640 (14)	0.0447 (14)	0.0588 (14)	0.0064 (11)	0.0079 (11)	0.0044 (11)
C7	0.092 (2)	0.082 (2)	0.085 (2)	0.0076 (16)	0.0389 (16)	−0.0107 (16)
C8	0.110 (2)	0.115 (3)	0.092 (2)	−0.026 (2)	0.0457 (19)	−0.0211 (19)
C9	0.0748 (16)	0.0750 (19)	0.0764 (19)	0.0108 (14)	0.0102 (13)	0.0226 (14)
C10	0.0540 (13)	0.0447 (13)	0.0571 (14)	0.0039 (10)	0.0076 (10)	0.0006 (11)
C11	0.0666 (15)	0.0505 (14)	0.0639 (16)	−0.0002 (11)	−0.0017 (12)	−0.0025 (12)
C12	0.0791 (17)	0.0751 (18)	0.0602 (17)	0.0074 (14)	−0.0033 (13)	−0.0020 (14)
C13	0.0807 (18)	0.084 (2)	0.0649 (17)	0.0115 (16)	0.0091 (13)	0.0192 (16)
C14	0.0725 (17)	0.0602 (17)	0.089 (2)	0.0006 (13)	0.0147 (15)	0.0154 (15)
C15	0.0653 (14)	0.0440 (13)	0.0696 (16)	0.0002 (11)	0.0109 (12)	0.0017 (12)

Geometric parameters (Å, º) top

O1—C6	1.327 (3)	C7—H7B	0.9700
O1—C7	1.459 (3)	C8—H8A	0.9600
O2—C6	1.198 (3)	C8—H8B	0.9600
N1—C4	1.325 (3)	C8—H8C	0.9600
N1—C3	1.343 (3)	C9—H9A	0.9600
N2—C2	1.367 (3)	C9—H9B	0.9600
N2—N4	1.370 (3)	C9—H9C	0.9600
N2—C3	1.380 (3)	C10—C11	1.390 (3)
N3—C3	1.334 (3)	C10—C15	1.395 (3)
N3—C1	1.343 (4)	C11—C12	1.372 (3)
N4—C1	1.325 (4)	C11—H11	0.9300
C1—H1A	0.9300	C12—C13	1.388 (4)
C2—C5	1.372 (3)	C12—H12	0.9300
C2—C9	1.490 (3)	C13—C14	1.365 (4)
C4—C5	1.432 (3)	C13—H13	0.9300
C4—C10	1.482 (3)	C14—C15	1.384 (3)
C5—C6	1.506 (3)	C14—H14	0.9300
C7—C8	1.459 (4)	C15—H15	0.9300
C7—H7A	0.9700

C6—O1—C7	116.0 (2)	C7—C8—H8A	109.5
C4—N1—C3	117.0 (2)	C7—C8—H8B	109.5
C2—N2—N4	127.0 (2)	H8A—C8—H8B	109.5
C2—N2—C3	123.3 (2)	C7—C8—H8C	109.5
N4—N2—C3	109.8 (2)	H8A—C8—H8C	109.5
C3—N3—C1	102.2 (3)	H8B—C8—H8C	109.5
C1—N4—N2	100.7 (2)	C2—C9—H9A	109.5
N4—C1—N3	117.9 (3)	C2—C9—H9B	109.5
N4—C1—H1A	121.0	H9A—C9—H9B	109.5
N3—C1—H1A	121.0	C2—C9—H9C	109.5
N2—C2—C5	114.7 (2)	H9A—C9—H9C	109.5
N2—C2—C9	117.3 (2)	H9B—C9—H9C	109.5
C5—C2—C9	128.0 (2)	C11—C10—C15	118.5 (2)
N3—C3—N1	128.6 (3)	C11—C10—C4	121.9 (2)
N3—C3—N2	109.4 (2)	C15—C10—C4	119.6 (2)
N1—C3—N2	122.0 (2)	C12—C11—C10	120.8 (2)
N1—C4—C5	122.2 (2)	C12—C11—H11	119.6
N1—C4—C10	116.6 (2)	C10—C11—H11	119.6
C5—C4—C10	121.20 (18)	C11—C12—C13	120.1 (3)
C2—C5—C4	120.8 (2)	C11—C12—H12	119.9
C2—C5—C6	118.2 (2)	C13—C12—H12	119.9
C4—C5—C6	120.97 (19)	C14—C13—C12	119.7 (3)
O2—C6—O1	124.5 (2)	C14—C13—H13	120.2
O2—C6—C5	124.9 (2)	C12—C13—H13	120.2
O1—C6—C5	110.6 (2)	C13—C14—C15	120.7 (3)
C8—C7—O1	108.1 (2)	C13—C14—H14	119.6
C8—C7—H7A	110.1	C15—C14—H14	119.6
O1—C7—H7A	110.1	C14—C15—C10	120.0 (2)
C8—C7—H7B	110.1	C14—C15—H15	120.0
O1—C7—H7B	110.1	C10—C15—H15	120.0
H7A—C7—H7B	108.4

C2—N2—N4—C1	−179.8 (2)	C10—C4—C5—C2	177.0 (2)
C3—N2—N4—C1	−0.3 (2)	N1—C4—C5—C6	174.1 (2)
N2—N4—C1—N3	0.3 (3)	C10—C4—C5—C6	−6.1 (3)
C3—N3—C1—N4	−0.2 (3)	C7—O1—C6—O2	−11.1 (3)
N4—N2—C2—C5	178.28 (19)	C7—O1—C6—C5	170.1 (2)
C3—N2—C2—C5	−1.2 (3)	C2—C5—C6—O2	−58.0 (3)
N4—N2—C2—C9	−0.4 (3)	C4—C5—C6—O2	125.1 (3)
C3—N2—C2—C9	−179.9 (2)	C2—C5—C6—O1	120.8 (2)
C1—N3—C3—N1	−179.8 (3)	C4—C5—C6—O1	−56.1 (3)
C1—N3—C3—N2	0.0 (3)	C6—O1—C7—C8	−159.8 (2)
C4—N1—C3—N3	−179.8 (2)	N1—C4—C10—C11	137.2 (2)
C4—N1—C3—N2	0.5 (3)	C5—C4—C10—C11	−42.6 (3)
C2—N2—C3—N3	179.8 (2)	N1—C4—C10—C15	−42.9 (3)
N4—N2—C3—N3	0.2 (3)	C5—C4—C10—C15	137.3 (2)
C2—N2—C3—N1	−0.4 (4)	C15—C10—C11—C12	−3.2 (3)
N4—N2—C3—N1	−180.0 (2)	C4—C10—C11—C12	176.6 (2)
C3—N1—C4—C5	1.1 (3)	C10—C11—C12—C13	0.3 (4)
C3—N1—C4—C10	−178.75 (19)	C11—C12—C13—C14	2.2 (4)
N2—C2—C5—C4	2.6 (3)	C12—C13—C14—C15	−1.7 (4)
C9—C2—C5—C4	−178.8 (2)	C13—C14—C15—C10	−1.3 (4)
N2—C2—C5—C6	−174.28 (19)	C11—C10—C15—C14	3.7 (3)
C9—C2—C5—C6	4.3 (4)	C4—C10—C15—C14	−176.1 (2)
N1—C4—C5—C2	−2.8 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C9—H9B···O2	0.96	2.58	3.127 (4)	116
C15—H15···O2ⁱ	0.93	2.57	3.246 (3)	129

Symmetry code: (i) x, y−1, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C9—H9B···O2	0.96	2.58	3.127 (4)	116
C15—H15···O2ⁱ	0.93	2.57	3.246 (3)	129

Symmetry code: (i) x, y−1, z.

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Volume 70| Part 6| June 2014| Pages o672-o673

doi:10.1107/S1600536814010113

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