2-Amino-5-methyl­pyridinium nicotinate

Madhukar Hemamalini; Hoong-Kun Fun

doi:10.1107/S1600536810005970

. 2010 Feb 20;66(Pt 3):o662. doi: 10.1107/S1600536810005970

2-Amino-5-methylpyridinium nicotinate

Madhukar Hemamalini ^a, Hoong-Kun Fun ^a,^*,^‡

PMCID: PMC2983647 PMID: 21580410

Abstract

In the title compound, C₆H₉N₂ ⁺·C₆H₄NO₂ ⁻, the 2-amino-5-methylpyridinium cation is essentially planar, with a maximum deviation of 0.023 (2) Å. In the crystal, the cations and anions are linked via strong N—H⋯O hydrogen bonds, forming a two dimensional network parallel to (100). In addition, π⋯π interactions involving the pyridinium and pyridine rings, with centroid–centroid distances of 3.6383 (8) Å, are observed.

Related literature

For background to the chemistry of substituted pyridines, see: Pozharski et al. (1997 ▶); Katritzky et al. (1996 ▶). For nicotinic acid, see: Athimoolam & Rajaram (2005 ▶); Lorenzen et al. (2001 ▶); Gielen et al. (1992 ▶); Kim et al. (2004 ▶). For a related structure, see: Nahringbauer & Kvick (1977 ▶). For details of hydrogen bonding, see: Jeffrey & Saenger (1991 ▶); Jeffrey (1997 ▶); Scheiner (1997 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₆H₉N₂ ⁺·C₆H₄NO₂ ⁻
M _r = 231.25
Monoclinic,
a = 9.4877 (3) Å
b = 11.1403 (3) Å
c = 11.7611 (3) Å
β = 110.113 (2)°
V = 1167.29 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 296 K
0.63 × 0.11 × 0.11 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.944, T _max = 0.990
14482 measured reflections
3870 independent reflections
2240 reflections with I > 2σ(I)
R _int = 0.026

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.144
S = 1.05
3870 reflections
195 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810005970/sj2728sup1.cif

e-66-0o662-sup1.cif^{(16.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810005970/sj2728Isup2.hkl

e-66-0o662-Isup2.hkl^{(185.9KB, 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
N1—H1N1⋯O2ⁱ	0.988 (16)	1.703 (16)	2.6899 (15)	176.8 (16)
N2—H1N2⋯O2ⁱⁱ	0.883 (16)	1.999 (16)	2.8756 (17)	171.7 (15)
N2—H2N2⋯O1ⁱ	0.936 (18)	1.878 (18)	2.8122 (17)	176.6 (17)

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

MH and HKF thank the Malaysian Government and Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012. MH thanks Universiti Sains Malaysia for a post-doctoral research fellowship.

supplementary crystallographic information

Comment

Pyridine and its derivatives play important roles in heterocyclic chemistry (Pozharski et al., 1997; Katritzky et al., 1996). They are often involved in hydrogen-bond interactions (Jeffrey & Saenger, 1991; Jeffrey, 1997; Scheiner, 1997). Nicotinic acid (vitamin B3), known as niacin, is a lipid lowering agent widely used to treat hypertriglyceridemia by the inhibition of lipolysis in adipose tissue (Athimoolam & Rajaram, 2005). The nicotinic acid complex 5-methylpyrazine-2-carboxylic acid-4-oxide is a commonly used drug for the treatment of hypercholesterolemia (Lorenzen et al., 2001). Coordination complexes of nicotinic acid with metals such as Sn possess antitumour activity greater than the well known cisplatin or doxorubicin (Gielen et al., 1992). The enzyme nicotinic acid mononucleotide adenyltransferase is essential for the synthesis of nicotinamide adenine dinucleotide in all living cells and is a potential target for antibiotics (Kim et al., 2004). Since our aim is to study some interesting hydrogen bonding interactions, the crystal structure of the title compound is presented here.

The asymmetric unit (Fig. 1) contains one 2-amino-5-methylpyridinium cation and one nicotinate anion. The proton transfer from the carboxyl group to atom N1 of 2-amino-5-methylpyridine resulted in the widening of C1—N1—C5 angle of the pyridinium ring to 122.61 (11)°, compared to the corresponding angle of 117.4° in neutral 2-amino-5-methylpyridine (Nahringbauer & Kvick, 1977). The 2-amino-5-methylpyridinium cation is essentially planar, with a maximum deviation of 0.023 (2)Å for atom C6. The bond lengths are normal (Allen et al., 1987).

In the crystal packing (Fig. 2), the protonated N1 atom and the 2-amino group (N2) is hydrogen-bonded to the carboxylate oxygen atoms (O1 and O2) via a pair of intermolecular N1—H1N1···O2 and N2—H2N2···O1 hydrogen bonds forming an R₂²(8) ring motif (Bernstein et al., 1995). The intermolecular N2—H1N2···O2 hydrogen bonds connect these molecules into 2-dimensional networks parallel to the (100)-plane (see Table 1). The crystal structure is further stabilized by π···π interactions involving the pyridine (C7–C11/N3) and pyridinium (C1–C5/N1) rings, with centroid to centroid distance of 3.6383 (8)Å [symmetry code: 1-x, 1-y, 1-z].

Experimental

A hot methanol solution (20 ml) of 2-amino-5-methylpyridine (54 mg, Aldrich) and nicotinic acid (62 mg, Merck) were mixed and warmed over a heating magnetic stirrer for a few minutes. The resulting solution was allowed to cool slowly at room temperature and crystals of the title compound appeared after a few days.