2-Amino-4,6-dimethyl­pyrimidine–4-hydroxy­benzoic acid (1/1)

Balasubramani, K.; Muthiah, P.T.; Lynch, D.E.

doi:10.1107/S1600536806022239

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 62| Part 7| July 2006| Pages o2907-o2909

https://doi.org/10.1107/S1600536806022239

2-Amino-4,6-dimethylpyrimidine–4-hydroxybenzoic acid (1/1)

Kasthuri Balasubramani,^a Packianathan Thomas Muthiah ^a ^* and Daniel E. Lynch ^b

^aSchool of Chemistry, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India, and ^bFaculty of Health and Life Sciences, Coventry University, Coventry CV1 5FB, England
^*Correspondence e-mail: tommtrichy@yahoo.co.in

(Received 23 May 2006; accepted 10 June 2006; online 21 June 2006)

In the title compound, C₆H₉N₃·C₇H₆O₃, the 2-amino-4,6-dimethylpyrimidine and 4-hydroxybenzoic acid molecules link together via N—H⋯O and O—H⋯N hydrogen bonds to form an eight-membered R₂²(8) ring. Further hydrogen bonds and C—H⋯O interactions result in the formation of a three-dimensional network.

Comment

The crystal structures of various aminopyrimidine carboxylates (Hu et al., 2002 ) and cocrystals (Chinnakali et al., 1999 ) have been described. From our laboratory, the crystal structures of 2-amino-4,6-dimethylpyrimidinium bromide 2-amino-4,6-dimethylpyrimidine monohydrate (Panneerselvam et al., 2004 ) and 2-amino-4,6-dimethylpyrimidine cinnamic acid (1/2) (Balasubramani et al., 2005 ) have been reported. In this paper, the hydrogen-bonding patterns in the title compound, (I), are described.

The asymmetric unit of (I) contains a 2-amino-4,6-dimethylpyrimidine (AMPY) molecule and a 4-hydroxybenzoic (4-HBZ) acid molecule (Fig. 1). Both species are neutral, thus (I) is an adduct rather than a molecular salt. Atoms O2 and the –N2H₂ group act as hydrogen-bond donors to atoms N1 and O3, respectively, to form an eight-membered ring, which has the graph-set notation R₂²(8) (Etter, 1990 ; Bernstein et al., 1995 ). This type of interaction has been observed in the crystal structures of other 2-aminopyrimidine–carboxylic acid adducts (Lynch & Jones, 2004 ).

The second H atom of the 2-amino group links to an O2 atom in an adjacent molecule via an N—H⋯O bond, and one of the C atoms (C11) of 4-HBZ is hydrogen bonded to O3 via a C—H⋯O interaction to form a ring having graph-set notation R₂³(8), leading to the supramolecular chain shown in Fig. 2. Hence, O3 acts as a bifurcated acceptor. The 4-HBZ hydroxy (O1) group is hydrogen bonded to pyrimidine atom N3 via an O—H⋯N interaction, to form a chain as shown in Fig. 3.

Aromatic π–π interactions between the pyrimidine ring of AMPY and the benzene ring of 4-HBZ are also observed in (I). The perpendicular separation is 3.552 Å, and the centroid-to-centroid distance is 3.660 (9) Å. The slip angle (the angle between the centroid-to-centroid vector and the normal to the plane) is 19.86°. These values are typical for aromatic π–π stacking interactions (Hunter, 1994 ).

Figure 1
ORTEPII (Johnson, 1976

) view of the asymmetric unit of (I)

, showing 50% probability displacement ellipsoids. Dashed lines indicate hydrogen bonds.

Figure 2
A view of the supramolecular chain in (I)

. Dashed lines indicate hydrogen bonds and H atoms not involved in hydrogen bonding have been omitted. [Symmetry codes: (ii) x, −y, $[{1\over 2}]$ + z; (iii) x, −y, z − $[{1\over 2}]$ .]

Figure 3
A view of the hydrogen-bonding patterns in (I)

. Dashed lines indicate hydrogen bonds and H atoms not involved in hydrogen bonding have been omitted. [Symmetry code: (i) 1 + x, −y, z − $[{1\over 2}]$ .]

Experimental

Hot methanol solutions (20 ml) of 2-amino-4,6-dimethylpyrimidine (30 mg, Aldrich) and 4-hydroxybenzoic acid (32 mg, LOBA Chemie, India) were mixed and warmed over a water bath for a few minutes. The resulting solution was allowed to cool slowly at room temperature. Crystals of (I) appeared from the mother liquor after a few days.

Crystal data

C₆H₉N₃·C₇H₆O₃
M_r = 261.28
Monoclinic, C c
a = 9.0693 (3) Å
b = 11.1141 (4) Å
c = 12.6080 (5) Å
β = 102.916 (2)°
V = 1238.70 (8) Å³
Z = 4
D_x = 1.401 Mg m⁻³
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 120 (2) K
Cube, colourless
0.20 × 0.20 × 0.20 mm

Data collection

Bruker–Nonius KappaCCD diffractometer
φ and ω scans
Absorption correction: multi-scan (SORTAV; Blessing, 1995 ) T_min = 0.980, T_max = 0.980
4983 measured reflections
1419 independent reflections
1360 reflections with I > 2σ(I)
R_int = 0.023
θ_max = 27.5°

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.058
wR(F²) = 0.130
S = 1.34
1419 reflections
177 parameters
H-atom parameters constrained
w = 1/[σ²(F_o²) + (0.0826P)²] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max < 0.001
Δρ_max = 0.97 e Å⁻³
Δρ_min = −0.93 e Å⁻³
Extinction correction: SHELXL97
Extinction coefficient: 0.171 (13)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯N3ⁱ	0.82	1.94	2.742 (3)	167
O2—H2⋯N1	0.82	1.90	2.711 (3)	173
N2—H2A⋯O3	0.86	2.00	2.843 (3)	168
N2—H2B⋯O2ⁱⁱ	0.86	2.56	3.229 (3)	135
C15—H15⋯O3ⁱⁱⁱ	0.93	2.55	3.181 (3)	126
Symmetry codes: (i) $[x+1, -y, z-{\script{1\over 2}}]$ ; (ii) $[x, -y, z+{\script{1\over 2}}]$ ; (iii) $[x, -y, z-{\script{1\over 2}}]$ .

In the absence of significant anomalous scattering effects, Friedel pairs were averaged. All the H atoms were positioned geometrically (C—H = 0.93–0.96 Å, N—H = 0.86 Å and O—H = 0.82 Å) and refined as riding, with U_iso(H) = 1.2U_eq(carrier).

Data collection: DENZO (Otwinowski & Minor, 1997 ) and COLLECT (Hooft, 1998 ); cell refinement: DENZO and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003 ) and ORTEPII (Johnson, 1976 ); software used to prepare material for publication: PLATON.

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536806022239/hb2063sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536806022239/hb2063Isup2.hkl

Computing details top

Data collection: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); cell refinement: DENZO and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003) and ORTEPII (Johnson, 1976); software used to prepare material for publication: PLATON.

2-Amino-4,6-dimethylpyrimidine–4-hydroxybenzoic acid (1/1) top

Crystal data top

C₆H₉N₃·C₇H₆O₃	F(000) = 552
M_r = 261.28	D_x = 1.401 Mg m⁻³
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C -2yc	Cell parameters from 25 reflections
a = 9.0693 (3) Å	θ = 2.9–26.0°
b = 11.1141 (4) Å	µ = 0.10 mm⁻¹
c = 12.6080 (5) Å	T = 120 K
β = 102.916 (2)°	Cube, colourless
V = 1238.70 (8) Å³	0.20 × 0.20 × 0.20 mm
Z = 4

Data collection top

Bruker Nonius KappaCCD diffractometer	1419 independent reflections
Radiation source: fine-focus sealed tube	1360 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.023
φ and ω scans	θ_max = 27.5°, θ_min = 3.3°
Absorption correction: multi-scan (SORTAV; Blessing, 1995)	h = −11→11
T_min = 0.980, T_max = 0.980	k = −14→14
4983 measured reflections	l = −13→16

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.058	H-atom parameters constrained
wR(F²) = 0.130	w = 1/[σ²(F_o²) + (0.0826P)²] where P = (F_o² + 2F_c²)/3
S = 1.34	(Δ/σ)_max < 0.001
1419 reflections	Δρ_max = 0.97 e Å⁻³
177 parameters	Δρ_min = −0.93 e Å⁻³
2 restraints	Extinction correction: SHELXL97, FC^*=KFC[1+0.001XFC²Λ³/SIN(2Θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.171 (13)

Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F² for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating -R-factor-obs etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

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

	x	y	z	U_iso*/U_eq
N1	0.8055 (2)	0.11658 (19)	0.07773 (16)	0.0171 (5)
N2	0.9130 (2)	0.0797 (2)	0.25815 (18)	0.0236 (6)
N3	0.6766 (2)	0.1679 (2)	0.21803 (17)	0.0187 (6)
C2	0.7952 (3)	0.1219 (2)	0.1826 (2)	0.0176 (7)
C4	0.6897 (3)	0.1626 (2)	0.0032 (2)	0.0183 (7)
C5	0.5650 (3)	0.2122 (2)	0.0327 (2)	0.0198 (7)
C6	0.5633 (3)	0.2143 (2)	0.1422 (2)	0.0183 (7)
C7	0.4343 (3)	0.2693 (2)	0.1815 (2)	0.0232 (7)
C8	0.7040 (3)	0.1597 (2)	−0.1131 (2)	0.0219 (7)
O1	1.67254 (19)	−0.16175 (18)	−0.06525 (15)	0.0243 (5)
O2	1.0396 (2)	0.03521 (19)	−0.00365 (15)	0.0224 (5)
O3	1.1621 (2)	0.0095 (2)	0.16966 (16)	0.0278 (6)
C9	1.1602 (3)	0.0057 (2)	0.0723 (2)	0.0183 (7)
C10	1.2931 (3)	−0.0348 (2)	0.0317 (2)	0.0174 (7)
C11	1.4103 (3)	−0.0928 (2)	0.1046 (2)	0.0193 (7)
C12	1.5354 (3)	−0.1350 (2)	0.0711 (2)	0.0208 (7)
C13	1.5476 (3)	−0.1186 (2)	−0.0367 (2)	0.0189 (7)
C14	1.4314 (3)	−0.0591 (2)	−0.1096 (2)	0.0193 (6)
C15	1.3049 (3)	−0.0179 (2)	−0.0759 (2)	0.0188 (7)
H2A	0.99090	0.05080	0.23860	0.0280*
H2B	0.91050	0.08170	0.32590	0.0280*
H5	0.48480	0.24330	−0.01930	0.0240*
H7A	0.36070	0.20840	0.18560	0.0350*
H7B	0.38820	0.33100	0.13170	0.0350*
H7C	0.47120	0.30370	0.25230	0.0350*
H8A	0.79730	0.19730	−0.11870	0.0330*
H8B	0.62070	0.20230	−0.15770	0.0330*
H8C	0.70320	0.07770	−0.13720	0.0330*
H1	1.66190	−0.15700	−0.13140	0.0360*
H2	0.97110	0.05580	0.02520	0.0340*
H11	1.40370	−0.10310	0.17660	0.0230*
H12	1.61190	−0.17450	0.12020	0.0250*
H14	1.43910	−0.04720	−0.18120	0.0230*
H15	1.22790	0.02100	−0.12500	0.0230*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0146 (9)	0.0201 (9)	0.0169 (10)	−0.0011 (7)	0.0043 (7)	−0.0004 (7)
N2	0.0208 (10)	0.0349 (12)	0.0161 (10)	0.0077 (9)	0.0061 (8)	0.0016 (9)
N3	0.0174 (9)	0.0214 (11)	0.0190 (10)	−0.0002 (8)	0.0075 (8)	−0.0005 (8)
C2	0.0163 (11)	0.0185 (11)	0.0186 (12)	−0.0017 (9)	0.0050 (9)	−0.0008 (9)
C4	0.0184 (11)	0.0181 (11)	0.0192 (12)	−0.0037 (9)	0.0056 (9)	−0.0012 (8)
C5	0.0168 (11)	0.0223 (12)	0.0201 (12)	0.0003 (9)	0.0038 (8)	0.0018 (9)
C6	0.0156 (11)	0.0178 (11)	0.0229 (12)	−0.0003 (9)	0.0071 (9)	0.0005 (9)
C7	0.0182 (11)	0.0271 (13)	0.0264 (13)	0.0044 (10)	0.0094 (10)	0.0015 (10)
C8	0.0228 (12)	0.0248 (12)	0.0185 (12)	0.0005 (10)	0.0055 (9)	0.0018 (9)
O1	0.0176 (9)	0.0367 (10)	0.0198 (9)	0.0058 (7)	0.0068 (7)	0.0003 (8)
O2	0.0161 (8)	0.0334 (10)	0.0181 (9)	0.0063 (7)	0.0049 (7)	−0.0015 (7)
O3	0.0190 (8)	0.0474 (12)	0.0180 (9)	0.0063 (8)	0.0062 (7)	−0.0025 (8)
C9	0.0171 (11)	0.0209 (11)	0.0174 (12)	−0.0014 (9)	0.0051 (9)	−0.0023 (9)
C10	0.0128 (11)	0.0207 (12)	0.0189 (12)	−0.0012 (9)	0.0042 (9)	−0.0020 (9)
C11	0.0191 (11)	0.0252 (12)	0.0145 (11)	−0.0013 (10)	0.0059 (9)	−0.0008 (9)
C12	0.0163 (11)	0.0264 (12)	0.0185 (12)	0.0023 (9)	0.0016 (9)	0.0004 (10)
C13	0.0162 (12)	0.0212 (12)	0.0203 (12)	−0.0008 (9)	0.0060 (9)	−0.0011 (9)
C14	0.0202 (11)	0.0234 (11)	0.0154 (11)	−0.0017 (9)	0.0065 (9)	−0.0019 (9)
C15	0.0167 (11)	0.0205 (11)	0.0184 (13)	−0.0013 (9)	0.0025 (9)	0.0002 (9)

Geometric parameters (Å, º) top

O1—C13	1.351 (3)	C7—H7A	0.9601
O2—C9	1.324 (3)	C7—H7C	0.9599
O3—C9	1.225 (3)	C7—H7B	0.9602
O1—H1	0.8196	C8—H8B	0.9598
O2—H2	0.8195	C8—H8C	0.9602
N1—C4	1.344 (3)	C8—H8A	0.9604
N1—C2	1.347 (3)	C9—C10	1.481 (4)
N2—C2	1.347 (3)	C10—C15	1.397 (4)
N3—C2	1.354 (3)	C10—C11	1.398 (4)
N3—C6	1.340 (3)	C11—C12	1.378 (4)
N2—H2B	0.8598	C12—C13	1.400 (4)
N2—H2A	0.8608	C13—C14	1.400 (4)
C4—C5	1.382 (4)	C14—C15	1.387 (4)
C4—C8	1.501 (4)	C11—H11	0.9301
C5—C6	1.384 (4)	C12—H12	0.9302
C6—C7	1.499 (4)	C14—H14	0.9303
C5—H5	0.9301	C15—H15	0.9298

C13—O1—H1	109.46	H8A—C8—H8B	109.47
C9—O2—H2	109.50	C4—C8—H8B	109.46
C2—N1—C4	117.0 (2)	C4—C8—H8C	109.47
C2—N3—C6	116.7 (2)	H8B—C8—H8C	109.48
C2—N2—H2B	120.05	H8A—C8—H8C	109.52
C2—N2—H2A	119.97	O2—C9—C10	115.5 (2)
H2A—N2—H2B	119.98	O3—C9—C10	121.8 (2)
N1—C2—N3	125.1 (2)	O2—C9—O3	122.7 (2)
N1—C2—N2	117.4 (2)	C11—C10—C15	119.2 (2)
N2—C2—N3	117.5 (2)	C9—C10—C11	118.1 (2)
N1—C4—C5	121.5 (2)	C9—C10—C15	122.7 (2)
N1—C4—C8	116.8 (2)	C10—C11—C12	120.8 (2)
C5—C4—C8	121.7 (2)	C11—C12—C13	120.2 (2)
C4—C5—C6	117.9 (2)	O1—C13—C14	123.1 (2)
N3—C6—C7	116.8 (2)	O1—C13—C12	117.7 (2)
N3—C6—C5	121.8 (2)	C12—C13—C14	119.2 (2)
C5—C6—C7	121.3 (2)	C13—C14—C15	120.5 (2)
C6—C5—H5	121.03	C10—C15—C14	120.1 (2)
C4—C5—H5	121.11	C10—C11—H11	119.55
C6—C7—H7C	109.52	C12—C11—H11	119.61
C6—C7—H7A	109.49	C11—C12—H12	119.95
C6—C7—H7B	109.45	C13—C12—H12	119.90
H7B—C7—H7C	109.51	C13—C14—H14	119.70
H7A—C7—H7B	109.41	C15—C14—H14	119.79
H7A—C7—H7C	109.44	C10—C15—H15	119.99
C4—C8—H8A	109.42	C14—C15—H15	119.94

C2—N1—C4—C8	178.2 (2)	O2—C9—C10—C11	−165.6 (2)
C4—N1—C2—N2	−177.8 (2)	O2—C9—C10—C15	14.0 (3)
C4—N1—C2—N3	1.2 (4)	O3—C9—C10—C11	13.3 (4)
C2—N1—C4—C5	−0.6 (3)	C15—C10—C11—C12	−1.1 (4)
C6—N3—C2—N2	177.2 (2)	C9—C10—C15—C14	−179.2 (2)
C2—N3—C6—C5	1.9 (3)	C9—C10—C11—C12	178.5 (2)
C2—N3—C6—C7	−177.9 (2)	C11—C10—C15—C14	0.4 (3)
C6—N3—C2—N1	−1.9 (4)	C10—C11—C12—C13	0.9 (4)
N1—C4—C5—C6	0.6 (4)	C11—C12—C13—O1	−180.0 (2)
C8—C4—C5—C6	−178.1 (2)	C11—C12—C13—C14	−0.1 (4)
C4—C5—C6—C7	178.4 (2)	C12—C13—C14—C15	−0.6 (4)
C4—C5—C6—N3	−1.3 (4)	O1—C13—C14—C15	179.3 (2)
O3—C9—C10—C15	−167.1 (2)	C13—C14—C15—C10	0.5 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N3ⁱ	0.82	1.94	2.742 (3)	167
O2—H2···N1	0.82	1.90	2.711 (3)	173
N2—H2A···O3	0.86	2.00	2.843 (3)	168
N2—H2B···O2ⁱⁱ	0.86	2.56	3.229 (3)	135
C15—H15···O3ⁱⁱⁱ	0.93	2.55	3.181 (3)	126

Symmetry codes: (i) x+1, −y, z−1/2; (ii) x, −y, z+1/2; (iii) x, −y, z−1/2.

Acknowledgements

DL thanks the EPSRC National Crystallography Service (Southampton, England) for the X-ray data collection.

References

Balasubramani, K., Muthiah, P. T., RajaRam, R. K. & Sridhar, B. (2005). Acta Cryst. E61, o4203–o4205. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Blessing, R. H. (1995). Acta Cryst. A51, 33–38. CrossRef CAS Web of Science IUCr Journals Google Scholar
Chinnakali, K., Fun, H.-K., Goswami, S., Mahapatra, A. K. & Nigam, G. D. (1999). Acta Cryst. C55, 399–401. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Etter, M. C. (1990). Acc. Chem. Res. 23, 120–126. CrossRef CAS Web of Science Google Scholar
Hooft, R. (1998). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
Hu, M.-L., Ye, M.-D., Zain, S. M. & Ng, S. W. (2002). Acta Cryst. E58, o1005–o1007. Web of Science CSD CrossRef IUCr Journals Google Scholar
Hunter, C. A. (1994). Chem. Soc. Rev. 23, 101–109. CrossRef CAS Web of Science Google Scholar
Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National Laboratory, Tennessee, USA. Google Scholar
Lynch, D. E. & Jones, G. D. (2004). Acta Cryst. B60, 748–754. Web of Science CrossRef CAS IUCr Journals Google Scholar
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology. Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press. Google Scholar
Panneerselvam, P., Muthiah, P. T. & Francis, S. (2004). Acta Cryst. E60, o747–o749. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany. Google Scholar
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13. Web of Science CrossRef CAS IUCr Journals Google Scholar

© International Union of Crystallography. Prior permission is not required to reproduce short quotations, tables and figures from this article, provided the original authors and source are cited. For more information, click here.