2-Amino-5-methyl­pyridinium 4-carb­oxy­butano­ate

Madhukar Hemamalini; Hoong-Kun Fun

doi:10.1107/S1600536810024451

. 2010 Jun 26;66(Pt 7):o1841–o1842. doi: 10.1107/S1600536810024451

2-Amino-5-methylpyridinium 4-carboxybutanoate

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

PMCID: PMC3006734 PMID: 21588042

Abstract

In the title salt, C₆H₉N₂ ⁺·C₅H₇O₄ ⁻, the 2-amino-5-methylpyridinium cation is essentially planar, with a maximum deviation of 0.008 (1) Å. In the crystal, the protonated N atom and the 2-amino group are hydrogen bonded to the carboxylate O atoms via a pair of N—H⋯O hydrogen bonds, forming an R ₂ ²(8) ring motif. The 4-carboxybutanoate anions are linked via O—H⋯O hydrogen bonds. The crystal structure is further stabilized by weak C—H⋯O interactions.

Related literature

For background to the chemistry of substituted pyridines, see: Pozharski et al. (1997 ▶); Katritzky et al. (1996 ▶). For applications of glutaric acid, see: Windholz (1976 ▶); Saraswathi et al. (2001 ▶). For details of hydrogen bonding, see: Jeffrey & Saenger (1991 ▶); Jeffrey (1997 ▶); Scheiner (1997 ▶). For related structures, see: Hemamalini & Fun (2010a ▶,b ▶); Fun et al. (2010 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For bond-length data, see: Allen et al. (1987 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₆H₉N₂ ⁺·C₅H₇O₄ ⁻
M _r = 240.26
Orthorhombic,
a = 5.3159 (10) Å
b = 14.383 (3) Å
c = 15.625 (3) Å
V = 1194.7 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 100 K
0.29 × 0.17 × 0.10 mm

Data collection

Bruker APEXII DUO CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.971, T _max = 0.990
7996 measured reflections
2028 independent reflections
1752 reflections with I > 2σ(I)
R _int = 0.037

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.109
S = 1.05
2028 reflections
156 parameters
H-atom parameters constrained
Δρ_max = 0.23 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/S1600536810024451/bv2141sup1.cif

e-66-o1841-sup1.cif^{(16.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810024451/bv2141Isup2.hkl

e-66-o1841-Isup2.hkl^{(97.7KB, 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—H1⋯O1ⁱ	0.86	1.82	2.672 (2)	170
N2—H2A⋯O2ⁱ	0.86	2.00	2.853 (3)	174
N2—H2B⋯O2	0.86	2.08	2.854 (2)	149
O4—H4⋯O1ⁱⁱ	0.82	1.76	2.5729 (19)	169
C2—H2⋯O3ⁱⁱⁱ	0.93	2.59	3.441 (2)	152
C5—H5⋯O3^iv	0.93	2.50	3.379 (2)	158

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

Acknowledgments

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

supplementary crystallographic information

Comment

Pyridine and its derivatives play an important role 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). Glutaric acid (pentanedioic acid) is a dicarboxylic acid with five carbon atoms, occurring in plant and animal tissues. Glutaric acid is found in the blood and urine. It is used in the synthesis of pharmaceuticals, surfactants and metal finishing compounds. Alpha-ketoglutaric acid is used in dietary supplements to improve protein synthesis (Windholz, 1976). We have recently reported the crystal structures of 2-amino-5-methylpyridinium 4-nitrobenzoate (Hemamalini & Fun, 2010a), 2-amino-5-methylpyridinium nicotinate (Fun et al., 2010) and 2-amino-5-methylpyridinium 3-aminobenzoate (Hemamalini & Fun, 2010b). In continuation of our studies of pyridinium derivatives, the crystal structure determination of the title compound has been undertaken.

The asymmetric unit (Fig. 1) contains a 2-amino-5-methylpyridinium cation and a 4-carboxybutanoate anion. The 2-amino-5-methylpyridinium cation is essentially planar, with a maximum deviation of 0.008 (1) Å for atom N1. In the 2-amino-5-methylpyridinium cation, a wide angle (123.09 (16)°) is subtended at the protonated N1 atom. The backbone conformation of the 4-carboxybutanoate anion can be described by the two torsion angles C11-C10-C9-C8 of -179.18 (14)° and C10-C9-C8-C7 of -72.74 (19)°. As evident from the torsion angles, the backbone is in a fully extended conformation (Saraswathi et al., 2001) of the two carboxyl groups, one is deprotonated while the other is not. The bond lengths (Allen et al., 1987) and angles are within normal ranges.

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—H1···O1 and N2—H2A···O2 hydrogen bonds forming a ring motif R₂²(8) (Bernstein et al., 1995). The 4-carboxybutanoate anions self-assemble via O4—H4···O1 hydrogen bonds. The crystal structure is further stabilized by weak C2—H2···O3 and C5—H5···O3 (Table 1) hydrogen bonds.

Experimental

A hot methanol solution (20 ml) of 2-amino-5-methylpyridine (27 mg, Aldrich) and glutaric acid (33 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.