N,N′-(4,5-Dimethyl-1,2-phenyl­ene)bis­(pyridine-2-carboxamide)

Phillipus C W Van der Berg; Hendrik G Visser; Andreas Roodt; Theunis J Muller

doi:10.1107/S1600536812035064

. 2012 Aug 23;68(Pt 9):o2739. doi: 10.1107/S1600536812035064

N,N′-(4,5-Dimethyl-1,2-phenylene)bis(pyridine-2-carboxamide)

Phillipus C W Van der Berg ^a,^*, Hendrik G Visser ^a, Andreas Roodt ^a, Theunis J Muller ^a

PMCID: PMC3435751 PMID: 22969622

Abstract

In the title compound, C₂₀H₁₈N₄O₂, the dihedral angles between the central benzene ring and the pyridine rings are 57.55 (6) and 22.05 (8)°. The molecular conformation is stabilized by intramolecular N—H⋯N interactions and in the crystal structure an intermolecular asymmetric cyclic hydrogen-bonding association involving both amide N—H donors and a common amide O-atom acceptor gives a chain extending along the c axis.

Related literature

For related structures, see: Jain et al. (2004 ▶); Lin et al. (2001 ▶); Roodt et al. (2011 ▶); Schutte et al. (2011 ▶); Van der Berg et al. (2011 ▶).

Experimental

Crystal data

C₂₀H₁₈N₄O₂
M _r = 346.38
Monoclinic,
a = 12.1299 (8) Å
b = 18.9418 (8) Å
c = 7.7549 (4) Å
β = 100.375 (4)°
V = 1752.65 (17) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 K
0.78 × 0.08 × 0.07 mm

Data collection

Bruker X8 APEXII KappaCCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ▶) T _min = 0.990, T _max = 0.994
15674 measured reflections
3860 independent reflections
3529 reflections with I > 2σ(I)
R _int = 0.031

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.090
S = 1.04
3860 reflections
237 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Data collection: APEX2 (Bruker, 2010 ▶); cell refinement: SAINT-Plus (Bruker, 2004 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812035064/zs2225sup1.cif

e-68-o2739-sup1.cif^{(19.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812035064/zs2225Isup2.hkl

e-68-o2739-Isup2.hkl^{(185.4KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2′⋯N1	0.86 (2)	2.20 (2)	2.6698 (19)	114.2 (16)
N2—H2′⋯N3	0.86 (2)	2.48 (2)	2.777 (2)	101.2 (15)
N2—H2′⋯O2ⁱ	0.86 (2)	2.60 (2)	3.2112 (19)	129.0 (17)
N3—H3′⋯O2ⁱ	0.86 (2)	2.05 (2)	2.8508 (19)	155.5 (18)
N3—H3′⋯N4	0.86 (2)	2.28 (2)	2.6670 (19)	107.8 (15)

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors would like to thank the Department of Chemistry of the University of the Free State, the NRF, NTeMBI, THRIP and Sasol Ltd for funding.

supplementary crystallographic information

Comment

The title compound C₂₀H₁₈N₄O₂ was synthesized as a ligand for potential use in medical and radiopharmaceutical applications. In this compound, which has one molecule in the asymmetric unit (Fig. 1), the dihedral angles between the central benzene ring and the pyridine rings are 57.55 (6) and 22.05 (8)°. The molecular conformation is stabilized by intramolecular N—H···N interactions and in the crystal structure an intermolecular asymmetric cyclic hydrogen-bonding association involving both amide N—H donors and a common amide O-atom acceptor (O2ⁱ) (Table 1), give a one-dimensional chain extending along c. The related structures from Roodt et al. (2011) and Schutte et al. (2011) also contribute to our studies in radiopharmaceutical design and reactivity.

Experimental

Under oxygen atmosphere, picolinic acid (5.73 g, 0.0465 mol) was added as a solid in one portion to a suspension of 4,5-dimethyl-1,2-phenylenediamine (3.00 g, 0.0220 mol) in pyridine (20 ml) and the mixture was stirred at 40 °C for 40 min. Triphenylphosphite (30 ml) was added dropwise over 10 minutes after which the temperature was increased to 90–100 °C and stirred for a further 24 h. On cooling the precipitate was filtered, washed with H₂O (50 ml) and then MeOH (50 ml). The precipitate was recrystallized in chloroform to giving colourless crystals after five days