2-Amino-5-methyl­pyridinium 6-oxo-1,6-dihydro­pyridine-2-carboxyl­ate

Kaliyaperumal Thanigaimani; Abbas Farhadikoutenaei; Nuridayanti Che Khalib; Suhana Arshad; Ibrahim Abdul Razak

doi:10.1107/S1600536812041359

. 2012 Oct 20;68(Pt 11):o3151–o3152. doi: 10.1107/S1600536812041359

2-Amino-5-methylpyridinium 6-oxo-1,6-dihydropyridine-2-carboxylate

Kaliyaperumal Thanigaimani ^a, Abbas Farhadikoutenaei ^a, Nuridayanti Che Khalib ^a, Suhana Arshad ^a, Ibrahim Abdul Razak ^a,^*,^‡

PMCID: PMC3515249 PMID: 23284469

Abstract

The anion of the title salt, C₆H₉N₂ ⁺·C₆H₄NO₃ ⁻, undergoes an enol-to-keto tautomerism during the crystallization. In the crystal structure, the cation and anion are held together by a relatively short N—H⋯O hydrogen bond, and the two anions are further connected to each other by a pair of N—H⋯O hydrogen bonds with an R ₂ ²(8) ring motif, thus forming a centrosymmetric 2 + 2 aggregate. The aggregates are further linked through weak N—H⋯O and C—H⋯O hydrogen bonds, resulting a three-dimensional network.

Related literature

For details of 2-aminopyridine and its derivatives, see: Banerjee & Murugavel (2004 ▶); Bis & Zaworotko (2005 ▶); Bis et al. (2006 ▶). For details of 6-hydroxypicolinic acid, see: Sun et al. (2004 ▶); Soares-Santos et al. (2003 ▶). For a related structure, see: Sawada & Ohashi (1998 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For bond-length data, see: Allen et al. (1987 ▶). For stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₆H₉N₂ ⁺·C₆H₄NO₃ ⁻
M _r = 247.25
Monoclinic,
a = 11.7093 (6) Å
b = 10.4594 (6) Å
c = 11.4590 (6) Å
β = 119.203 (1)°
V = 1225.03 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 100 K
0.45 × 0.35 × 0.23 mm

Data collection

Bruker SMART APEXII DUO CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.957, T _max = 0.978
15984 measured reflections
4430 independent reflections
3745 reflections with I > 2σ(I)
R _int = 0.027

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.116
S = 1.02
4430 reflections
180 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.43 e Å⁻³
Δρ_min = −0.21 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

Click here for additional data file.^{(22.4KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812041359/is5197sup1.cif

e-68-o3151-sup1.cif^{(22.4KB, cif)}

Click here for additional data file.^{(217.1KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812041359/is5197Isup2.hkl

e-68-o3151-Isup2.hkl^{(217.1KB, hkl)}

Click here for additional data file.^{(4.9KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536812041359/is5197Isup3.cml

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⋯O1ⁱ	0.899 (15)	2.011 (15)	2.8922 (10)	166.0 (16)
N3—H2N3⋯O1	0.900 (16)	2.245 (19)	3.0373 (12)	146.7 (15)
N3—H2N3⋯O3ⁱ	0.900 (16)	2.408 (16)	3.0916 (11)	133.0 (15)
N3—H1N3⋯O2ⁱⁱ	0.938 (15)	1.884 (16)	2.8071 (12)	167.7 (15)
N2—H1N2⋯O3ⁱ	0.954 (16)	1.686 (18)	2.6206 (11)	165.7 (17)
C3—H3A⋯O1ⁱⁱⁱ	0.95	2.33	3.2598 (11)	166
C9—H9A⋯O1^iv	0.95	2.54	3.3750 (12)	146

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

Acknowledgments

The authors thank the Malaysian Government and Universiti Sains Malaysia (USM) for research facilities and the Fundamental Research Grant Scheme (FRGS) No. 203/PFIZIK/6711171 to conduct this work. KT thanks The Academy of Sciences for the Developing World and USM for a TWAS–USM fellowship.

supplementary crystallographic information

Comment

2-Aminopyridine and its derivatives are some of the most frequently used synthons in supramolecular chemistry based on hydrogen bonds (Banerjee & Murugavel, 2004; Bis & Zaworotko, 2005; Bis et al., 2006). 6-Hydroxypicolinic acid has interesting characteristics: firstly, it was characterized by a similar enol-keto tautomerism due to the labile hydrogen atom of –OH group in α-position migrating easily to the basic pyridine N atom; secondly, the multiple coordination sites such as the carbonyl oxygen, the amide nitrogen and carboxylate oxygen atoms are able to coordinate with various metal ions (Sun et al., 2004; Soares-Santos et al., 2003). In order to study some interesting hydrogen bonding interactions of this compound, the synthesis and structure of the title salt is presented here.

The asymmetric unit of the title compound contains a 2-amino-5-methylpyridinium cation and a 6-oxo-1,6-dihydropyridine-2-carboxylate anion (Fig. 1). The 2-amino-5-methylpyridinium cation is planar, with a maximum deviation of 0.004 (1) Å for atoms N2 and C9. In the cation, a wider than normal angle [C11—N2—C12 = 122.96 (8)°] is subtended at the protonated N2 atom. The bond lengths (Allen et al., 1987) and angles are normal. The anion exists in the keto-enol tautomerism of the –CONH moiety. Similar form was also observed in the crystal structure of 2-oxo-1,2-dihydropyridine-6-carboxylic acid (Sawada & Ohashi, 1998).

In the crystal (Fig. 2), the 6-oxo-1,6-dihydropyridine-2-carboxylate anion are centrosymmetrically paired through a pair of N1—H1N1···O1ⁱ hydrogen bonds (symmetry code in Table 1) to form an R₂²(8) (Bernstein et al., 1995) ring motif. These motifs are further self-organized through N—H···O hydrogen bonds to generate an array of four hydrogen bonds, resulting in the rings with R₂²(8), sandwiched by two R₂²(7). One of the O atoms of the carboxylate group acts as an acceptors of bifurcated N2—H1N2···O3ⁱ and N3—H2N3···O3ⁱ hydrogen bonds (symmetry code in Table 1) with the protonated pyridine and amine N atoms of the cation, forming an R₂¹(6) ring motif. The crystal structure are further stabilized by strong N3—H1N3···O2ⁱⁱ and weak C3—H3A···O1ⁱⁱⁱ and C9—H9A···O1^iv hydrogen bonds (symmetry codes in Table 1), resulting a three-dimensional network.

Experimental

Hot methanol solutions (20 ml) of 2-amino5-methylpyridine (54 mg, Aldrich) and 6-Hydroxypicolinic acid (69 mg, Merck) were mixed and warmed over a heating magnetic stirrer hotplate for a few minutes. The resulting solution was allowed to cool slowly at room temperature and crystals of the title compound (I) appeared after a few days.