organic compounds
4-Hydroxy-6-methylpyridin-2(1H)-one
aCentro de Graduados e Investigación del Instituto Tecnológico de Tijuana, Apdo. Postal 1166, 22500, Tijuana, B.C., Mexico
*Correspondence e-mail: dchavez@tectijuana.mx
In the 6H7NO2, N—H⋯O and O—H⋯O hydrogen bonds link the molecules, forming a zigzag array along [001] and a layer structure parallel to the ab plane.
of the title compound, CRelated literature
For the potential of related compounds in anti-HIV treatment, see: De Clercq (2005); Dollé et al. (1995); Medina-Franco et al. (2007).
Experimental
Crystal data
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Data collection: XSCANS (Siemens, 1996); cell XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S1600536813024240/im2437sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536813024240/im2437Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536813024240/im2437Isup3.cml
The synthesis of 4-hydroxy-6-methylpyridin-2(1H)-one includes reagents and reagent grade solvents, which were used without further purification. In a round bottom flask of 500 ml equipped with a magnetic stirrer was placed 10.0 g of ethyl 4-hydroxy-6-methyl-2-oxo-1,2-dihydropyridine-3-carboxylate (0.05 mol) in 350 ml of hydrochloric acid 1 N. The mixture was stirred at reflux for 72 h. 4-Hydroxy-6-methylpyridin-2(1H)-one precipitated as a white solid (6.2 g, 99%, m. p. 273–275 °C, for analytical data, see _exptl_special_details section). Crystals of the title compound suitable for Xray diffraction were obtained by dissolving 100 mg of 4-hydroxy-6-methyl-pyridine-2 (1H)-one in 10 ml of methanol-diethylether (1:1, v / v) and placing the solution in a glass vial. The solution was allowed to stand at room temperature for 7 days and the crystals formed were filtered.
All H atoms were positioned geometrically and refined using a riding model, with C—H = 0.93 Å for aryl and 0.96 Å for methyl H atoms. Isotropic thermal parameters were fixed to Uiso(H) = 1.2 Ueq(C) for aryl and Uiso(H) = 1.5 Ueq(C) for methyl H atoms.
Data collection: XSCANS (Siemens, 1996); cell
XSCANS (Siemens, 1996); data reduction: XSCANS (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C6H7NO2 | F(000) = 264 |
Mr = 125.13 | Dx = 1.430 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 51 reflections |
a = 4.7082 (5) Å | θ = 6.6–12.3° |
b = 12.2988 (8) Å | µ = 0.11 mm−1 |
c = 10.0418 (7) Å | T = 298 K |
β = 91.303 (7)° | Prismatic, colorless |
V = 581.32 (8) Å3 | 0.65 × 0.20 × 0.18 mm |
Z = 4 |
Bruker P4 diffractometer | 1269 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.026 |
Graphite monochromator | θmax = 30.0°, θmin = 2.6° |
2θ/ω scans | h = −1→6 |
Absorption correction: ψ scan (XSCANS; Siemens, 1996) | k = −1→17 |
Tmin = 0.216, Tmax = 0.259 | l = −14→14 |
2445 measured reflections | 3 standard reflections every 97 reflections |
1701 independent reflections | intensity decay: 9.4% |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.050 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.160 | H-atom parameters constrained |
S = 1.06 | w = 1/[σ2(Fo2) + (0.1P)2] where P = (Fo2 + 2Fc2)/3 |
1701 reflections | (Δ/σ)max < 0.001 |
82 parameters | Δρmax = 0.32 e Å−3 |
0 restraints | Δρmin = −0.25 e Å−3 |
C6H7NO2 | V = 581.32 (8) Å3 |
Mr = 125.13 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 4.7082 (5) Å | µ = 0.11 mm−1 |
b = 12.2988 (8) Å | T = 298 K |
c = 10.0418 (7) Å | 0.65 × 0.20 × 0.18 mm |
β = 91.303 (7)° |
Bruker P4 diffractometer | 1269 reflections with I > 2σ(I) |
Absorption correction: ψ scan (XSCANS; Siemens, 1996) | Rint = 0.026 |
Tmin = 0.216, Tmax = 0.259 | 3 standard reflections every 97 reflections |
2445 measured reflections | intensity decay: 9.4% |
1701 independent reflections |
R[F2 > 2σ(F2)] = 0.050 | 0 restraints |
wR(F2) = 0.160 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.32 e Å−3 |
1701 reflections | Δρmin = −0.25 e Å−3 |
82 parameters |
Experimental. IR: 3296, 3094, 2891, 1640 cm^-1. 1Ĥ NMR (CDCl~3~): δ 10.99 (s, NH-1), 10.40 (s, OH), 5.59 (s, H-3), 5.34 (s, H-5) 2.07 (s, 3H, CH~3~—C-6). ^13Ĉ NMR (CDCl~3~): δ 167.6, 164.8, 145.9, 98.2, 95.7, 18.5. MS m/e (int. rel): [M]^+^ 125 (100), 97 (16). |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) 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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.7844 (3) | 0.91089 (9) | 0.60053 (9) | 0.0364 (3) | |
O2 | 0.2045 (2) | 0.68616 (10) | 0.32761 (10) | 0.0396 (3) | |
H2B | 0.2292 | 0.6556 | 0.2562 | 0.059* | |
N1 | 0.7786 (3) | 0.93124 (10) | 0.37596 (11) | 0.0301 (3) | |
H1A | 0.9049 | 0.9813 | 0.3858 | 0.036* | |
C1 | 0.6811 (3) | 0.88072 (12) | 0.48782 (12) | 0.0288 (3) | |
C2 | 0.4786 (3) | 0.79830 (13) | 0.46911 (13) | 0.0326 (3) | |
H2A | 0.4026 | 0.7638 | 0.5426 | 0.039* | |
C3 | 0.3912 (3) | 0.76793 (12) | 0.34229 (13) | 0.0303 (3) | |
C4 | 0.4958 (3) | 0.82420 (12) | 0.23072 (14) | 0.0321 (3) | |
H4A | 0.4353 | 0.8053 | 0.1450 | 0.038* | |
C5 | 0.6858 (3) | 0.90624 (12) | 0.25012 (13) | 0.0293 (3) | |
C6 | 0.8049 (4) | 0.97389 (15) | 0.14088 (15) | 0.0403 (4) | |
H6D | 0.7267 | 0.9501 | 0.0567 | 0.060* | |
H6A | 1.0078 | 0.9662 | 0.1411 | 0.060* | |
H6B | 0.7566 | 1.0488 | 0.1548 | 0.060* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0491 (7) | 0.0370 (6) | 0.0227 (5) | −0.0064 (5) | −0.0062 (4) | 0.0009 (4) |
O2 | 0.0483 (7) | 0.0407 (6) | 0.0297 (5) | −0.0133 (5) | 0.0024 (5) | −0.0057 (4) |
N1 | 0.0360 (6) | 0.0315 (6) | 0.0227 (5) | −0.0037 (5) | −0.0032 (5) | 0.0022 (4) |
C1 | 0.0352 (7) | 0.0297 (7) | 0.0214 (6) | 0.0034 (6) | −0.0013 (5) | 0.0010 (5) |
C2 | 0.0399 (8) | 0.0340 (7) | 0.0238 (6) | −0.0026 (6) | 0.0015 (5) | 0.0009 (5) |
C3 | 0.0324 (7) | 0.0311 (7) | 0.0273 (6) | 0.0002 (6) | 0.0000 (5) | −0.0014 (5) |
C4 | 0.0380 (8) | 0.0357 (8) | 0.0224 (6) | 0.0007 (6) | −0.0021 (5) | −0.0023 (5) |
C5 | 0.0341 (7) | 0.0319 (7) | 0.0218 (6) | 0.0027 (6) | −0.0004 (5) | 0.0016 (5) |
C6 | 0.0534 (10) | 0.0420 (9) | 0.0255 (6) | −0.0049 (8) | 0.0007 (6) | 0.0068 (6) |
O1—C1 | 1.2768 (16) | C2—H2A | 0.9300 |
O2—C3 | 1.3418 (18) | C3—C4 | 1.415 (2) |
O2—H2B | 0.8200 | C4—C5 | 1.359 (2) |
N1—C5 | 1.3629 (17) | C4—H4A | 0.9300 |
N1—C1 | 1.3719 (17) | C5—C6 | 1.496 (2) |
N1—H1A | 0.8600 | C6—H6D | 0.9600 |
C1—C2 | 1.401 (2) | C6—H6A | 0.9600 |
C2—C3 | 1.3809 (19) | C6—H6B | 0.9600 |
C3—O2—H2B | 109.5 | C5—C4—C3 | 119.30 (13) |
C5—N1—C1 | 123.42 (13) | C5—C4—H4A | 120.4 |
C5—N1—H1A | 118.3 | C3—C4—H4A | 120.4 |
C1—N1—H1A | 118.3 | C4—C5—N1 | 119.76 (13) |
O1—C1—N1 | 117.79 (14) | C4—C5—C6 | 124.34 (13) |
O1—C1—C2 | 124.99 (13) | N1—C5—C6 | 115.90 (14) |
N1—C1—C2 | 117.21 (12) | C5—C6—H6D | 109.5 |
C3—C2—C1 | 120.46 (13) | C5—C6—H6A | 109.5 |
C3—C2—H2A | 119.8 | H6D—C6—H6A | 109.5 |
C1—C2—H2A | 119.8 | C5—C6—H6B | 109.5 |
O2—C3—C2 | 119.01 (13) | H6D—C6—H6B | 109.5 |
O2—C3—C4 | 121.24 (12) | H6A—C6—H6B | 109.5 |
C2—C3—C4 | 119.74 (14) | ||
C5—N1—C1—O1 | 179.84 (14) | O2—C3—C4—C5 | −179.71 (13) |
C5—N1—C1—C2 | 1.0 (2) | C2—C3—C4—C5 | 1.3 (2) |
O1—C1—C2—C3 | −176.62 (15) | C3—C4—C5—N1 | 1.8 (2) |
N1—C1—C2—C3 | 2.2 (2) | C3—C4—C5—C6 | −178.05 (15) |
C1—C2—C3—O2 | 177.69 (13) | C1—N1—C5—C4 | −3.0 (2) |
C1—C2—C3—C4 | −3.3 (2) | C1—N1—C5—C6 | 176.88 (14) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O1i | 0.86 | 1.98 | 2.835 (2) | 175 |
O2—H2B···O1ii | 0.82 | 1.79 | 2.609 (2) | 180 |
Symmetry codes: (i) −x+2, −y+2, −z+1; (ii) x−1/2, −y+3/2, z−1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O1i | 0.86 | 1.98 | 2.835 (2) | 175.4 |
O2—H2B···O1ii | 0.82 | 1.79 | 2.609 (2) | 179.8 |
Symmetry codes: (i) −x+2, −y+2, −z+1; (ii) x−1/2, −y+3/2, z−1/2. |
Acknowledgements
We gratefully acknowledge support for this project by the Dirección General de Educación Superior Tecnológica (DGEST grants 2535.09P and 3604.10-P).
References
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
The acquired immunodeficiency syndrome (AIDS) is a disease of people who are infected with human immunodeficiency virus (HIV). The use of drugs to fight HIV are called antiretroviral drugs and are characterized by inhibiting essential enzymes for virus replication, such as reverse transcriptase (De Clercq, 2005).
Pyridin-2 (1H)-one hybrids are a kind of compounds that inhibit the reverse transcription process and have been shown, by molecular modeling, their good performance as non-nucleoside inhibitors of HIV-1 reverse transcriptase. Recent design of the pyridin-2(1H)-one hybrids has generated active molecules against wild type and mutant strains of HIV, as in the case of second-generation hybrid pyridinone-UC781 (Medina-Franco et al.., 2007). In this work, and as part of our ongoing research, we have synthesized pyridin-2 (1H)-one hybrids (Dollé et al., 1995) of second generation with different polar groups at C-3 and also with different olefinic groups at C-4, similar to pyridinone-UC781. The compound 4-hydroxy-6-methylpyridin-2 (1H)-one is an intermediate in the synthesis of second-generation hybrids with a polar nitro group at C-3.
We have synthesized the title compound (I) and report its crystal structure here (Fig. 1). In the crystal structure adjacent networks are linked together via intermolecular hydrogen bond interactions (table 1) [N1—H1A···O1i (2.8349 Å), symmetry codes: (i) –x + 2, –y + 2, - z + 1] and [O2—H2B···O1ii (2.6086 Å), symmetry codes: (ii) x – 1/2, - y + 3/2, z – 1/2] to form a zigzag array along the [001] direction and molecules are forming a layer structure parallel to the ab plane (Fig. 2).