research communications
of 4-benzylcarbamoyl-1-methylpyridin-1-ium iodide: an efficient multimodal antiviral drug
aInstitute of Solid State Chemistry and Mechanochemistry, SB RAS, ul. Kutateladze 18, Novosibirsk 630128, Russian Federation, bNovosibirsk State University, ul. Pirogova 2, Novosibirsk 630090, Russian Federation, and cInstitute for the Problems of the Technology of Energetic Materials, SB RAS, ul. Socialisticheskaia 1, Biisk 659322, Russian Federation
*Correspondence e-mail: tanya@xray.nsu.ru
In the title compound, [MeC5H4NCONHCH2C6H5]I or C14H15N2O+·I−, a cation and an anion form an ionic pair linked by a strong N—H⋯I hydrogen bond. In the crystal, ionic pairs linked by weak C—H⋯I hydrogen bonds form infinite ribbons along the crystallographic a axis. screening varying crystallization solvents (water, acetone 90%–water, ethanol 90%–water, 2-propanol 90%–water, DMF, DMSO, methanol, acetonitrile) and conditions (solution temperature, heating and cooling protocols) did not reveal any other polymorphs than the one reported in this work.
Keywords: crystal structure; drug; polymorphism.
CCDC reference: 1553547
1. Chemical context
4-Benzylcarbamoyl-1-methylpyridin-1-ium iodide, [MeC5H4NCONHCH2C6H5]I, is a multimodal antiviral drug (Buhtiarova et al., 2003; Frolov et al., 2004). For pharmaceutical applications, it is of utmost importance to identify possible polymorphs (Bernstein, 2002; Brittain, 1999; Hilfiker, 2006), see also https://www.fda.gov/downloads/Drugs/Guidances/UCM072866.pdf; https://newdrugapprovals.org/2014/02/12/fda-guidance-on-polymorphic-compounds-in-generic-drugs/. screening varying crystallization solvents (water, acetone 90%–water, ethanol 90%–water, isopropanol 90%–water, DMF, DMSO, MeOH, CH3CN) and conditions (solution temperature, heating and cooling protocols) did not reveal any other polymorphs than the one reported in this work as has been confirmed by DSC (METTLER TOLEDO DSC 822e, 5° min−1 in N2, samples 1/6–3/5 mg), IR spectroscopy (IR–FT spectrometer FT–801, spectroscopic resolution 0.5 cm−1 and systematic error ±0,05 cm−1; samples studied in KBr discs, 1.0 mg of substance in 200 mg of KBr; 4000–600 cm−1, and FTIR ATR spectrometer DigiLab Excalibur 3100, Varian spectrometer equipped with a MIRacle ATR accessory in the range 4000–600 cm−1 with resolution of 2 cm−1 without addition of KBr) and X-ray powder diffraction (STOE STADI MP diffractometer, CuKα1 radiation, curved Ge monochromator, transmission mode). The same thermal effect at the DSC curves related to sample melting at 464 K has been observed for all the samples. The position and relative intensities of the bands in the IR spectra were also the same (see section 5, Fig. 1). There were no differences between the IR spectra recorded with and without addition of KBr. The X-ray diffraction patterns were also the same for all the samples (Fig. 2) and matched the pattern calculated for the structural model based on single-crystal diffraction data (see next sections). WinXPOW (Stoe & Cie, 2011) was used to analyze the diffraction patterns.
2. Structural commentary
The MeC5H4NCONHCH2C6H5]+ cation and an I− anion (Fig. 3). All the bond lengths and angles are within normal ranges. A cation and an anion form an ionic pair linked by a strong N2—H2⋯I1 hydrogen bond (Table 1). The central part of the molecule (N2/C8/O1) and the pyridyl ring are located practically in the same plane [the average deviation of the atoms from the N1/N2/O1/C8–C13 plane is 0.015 (3) Å and the maximum deviation is 0.025 (3) Å]. The I− anion is also close to this plane [at a distance of 0.504 (3) Å]. The dihedral angle between the pyridyl and benzene rings is 62.8 (1)°.
of the title compound contains a [3. Supramolecular features
In addition to the strong NH⋯I hydrogen bond, two weak C—H⋯I hydrogen bonds are present in the , Fig. 4). Ionic pairs linked by these hydrogen bonds form infinite ribbons along the crystallographic a axis (Fig. 4). No hydrogen bonds link the ribbons with each other.
(Table 14. Database survey
No crystal structures containing the [MeC5H4NCONHCH2C6H5]+ cation could be found in the Cambridge Structural Database (CSD, Version 5.38, update November 2016; Groom et al., 2016). A of 4-benzoylamino-1-methylpyridinium iodide (CSD refcode ESESUS; Navarro et al., 2016) is also formed by ionic pairs linked by a strong N—H⋯I hydrogen bond [the donor–acceptor distance is 3.675 (1) Å]. Similarly to the compound studied in this work, the organic cation of ESESUS also contains a benzene and an N-methylpyridine ring, with the N atom forming an N—H⋯I hydrogen bond in the centre of the cation (Fig. 5). Since the central part of the cation in the case of ESESUS is shorter than that of the title compound, the molecular conformation is very different, as is the molecular packing (Fig. 5).
5. Synthesis and crystallization
The title compound can be synthesized from N-benzylamide 4-pyridinecarboxylic acid C5H4NCONHCH2C6H5 and methyl iodide MeI in a 1:2 (Trinus et al., 1994) or 1:1.2 (Buhtiarova et al., 1997) molar ratio. N-Benzylamide 4-pyridinecarboxylic acid, in turn, was synthesized by the condensation of isonicotinic acid C5H4NCOOH with benzylamine C6H5CH2NH2 taken in a 1:2 molar ratio (Trinus et al., 1994).
12.31 g (0.1 mol) of isonicotinic acid were added with constant stirring over a period of one hour to 12.86 g (0.12 mol) of benzylamine heated to 413 K. After all of the isonicotinic acid had been added, the mixture was heated steadily to 493–503 K. After water and the excess of benzamine had been distilled, the residue was cooled to 373–383 K and added on stirring to 100 ml of toluene. The hot solution was filtered and cooled to 288 K. After cooling, the precipitate was filtered, washed on the filter with 20 ml of toluene and dried in the air at ambient temperature. The yield was 18.57 g (0.0875 mol; 87.5%) (Sysoljatin et al., 2011).
18.57 g (0.0875 mol) of N-benzylamide 4-pyridinecarboxylic acid were added to 110 ml of acetone with stirring. After the dissolution was complete, 14.9 g (0.105 mol) of methyl iodide MeI were added and the reaction mixture kept at 323 K for five h after which it was cooled to 283–288 K and filtered. The precipitate was washed on the filter with 50 ml of acetone and dried in the air. The yield was 24.65 g (0.0696 mol; 79.5%) (Sysoljatin et al., 2011).
Calculated for C14H15N2OI: C, 47.46; H, 4.21: N, 7.91; O, 4.52. Found: C, 47.31; H, 4.13: N, 7.62; O, 4.35. Tmelt. 464 K. IR spectrum (cm−1): 611.27, 631.44, 703.72, 777.41, 759.32, 860.4, 920.77, 960.85, 1020.8, 1078.2, 1147.6, 1187.8, 1218.8, 1285.4, 1329.8, 1416.4, 1452.5, 1505.1, 1541.1, 1571.6, 1663.7, 1641.4, 1828.1, 1950.9, 2828.6, 2936.6, 3040.4, 3237.6. 1H NMR (400 MHz, DMSO-d6, p.p.m.): δ = 4.40 (s, 3H, CH3), 4.55 (d, 2H, CH2), 7.22–7.45 (m, 5H, Ar), 8.44 (d, 2H, Py), 9.19 (d, 2H, Py), 9.78 (s, H, NH). 13C–1H NMR (100 MHz, DMSO-d6, p.p.m.): δ = 43.89 (CH2), 49.00 (CH3), 125.95, 147.06, 148.20 (Py), 127.65, 128.01, 128.92, 139.18 (Ar), 162.63 (C=O).
The pharmaceutical substance was obtained by recrystallization from an aqueous solution with et al., 2011). 5.0 g (0.014 mol) of N-methyl-4-benzylcarbamidopyridinium iodide were dissolved in 6 ml of water at 363 K and 0.15 g (3.0%) of added. After the complete dissolution of the compound, the was removed by filtering, and the solution was cooled to 283 K. After stirring for one hour, the precipitate formed was filtered through a paper filter (white band), washed with 10 ml of acetone and dried at 373 K. Yield 4.71 g (0.0133 mol; 94.3%).
(Sysoljatin6. Refinement
Crystal data, data collection and structure . The amine hydrogen atom bound to N2 was located in the difference maps and refined isotropically. All other hydrogen atoms were positioned geometrically and refined with a riding model [C—H = 0.93–0.97 Å; Uiso(H) = 1.2–1.5Ueq(C)].
details are summarized in Table 2Supporting information
CCDC reference: 1553547
https://doi.org/10.1107/S2056989017008155/rk2435sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989017008155/rk2435Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2056989017008155/rk2435Isup3.cml
Data collection: CrysAlis PRO (Rigaku OD, 2015); cell
CrysAlis PRO (Rigaku OD, 2015); data reduction: CrysAlis PRO (Rigaku OD, 2015); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: WinGX (Farrugia, 2012) and publCIF (Westrip, 2010).C14H15N2O+·I− | Dx = 1.629 Mg m−3 |
Mr = 354.18 | Melting point: 464(2) K |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
a = 9.2867 (2) Å | Cell parameters from 9574 reflections |
b = 10.8741 (2) Å | θ = 2.4–26.3° |
c = 14.3038 (3) Å | µ = 2.21 mm−1 |
V = 1444.46 (5) Å3 | T = 295 K |
Z = 4 | Block, yellow |
F(000) = 696 | 0.25 × 0.17 × 0.07 mm |
Rigaku OD Xcalibur, Ruby, Gemini ultra diffractometer | 3388 independent reflections |
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source | 3115 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.033 |
Detector resolution: 10.3457 pixels mm-1 | θmax = 28.3°, θmin = 2.4° |
ω scans | h = −12→12 |
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2015) | k = −14→13 |
Tmin = 0.910, Tmax = 1.000 | l = −18→18 |
18978 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: mixed |
R[F2 > 2σ(F2)] = 0.024 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.053 | w = 1/[σ2(Fo2) + (0.0267P)2 + 0.0479P] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max < 0.001 |
3388 reflections | Δρmax = 0.53 e Å−3 |
168 parameters | Δρmin = −0.35 e Å−3 |
0 restraints | Absolute structure: Flack x determined using 1207 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013) |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.033 (11) |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.1886 (4) | 0.0803 (3) | 0.9728 (2) | 0.0423 (8) | |
C2 | 0.2939 (4) | 0.0665 (4) | 1.0407 (3) | 0.0475 (9) | |
H1 | 0.3631 | 0.0054 | 1.0338 | 0.057* | |
C3 | 0.2982 (5) | 0.1404 (4) | 1.1172 (3) | 0.0583 (11) | |
H3 | 0.3702 | 0.1296 | 1.1617 | 0.070* | |
C4 | 0.1975 (6) | 0.2307 (5) | 1.1293 (3) | 0.0739 (13) | |
H4 | 0.2012 | 0.2817 | 1.1814 | 0.089* | |
C5 | 0.0909 (6) | 0.2452 (5) | 1.0639 (4) | 0.0805 (16) | |
H5 | 0.0210 | 0.3054 | 1.0723 | 0.097* | |
C6 | 0.0869 (5) | 0.1713 (4) | 0.9858 (3) | 0.0654 (12) | |
H6 | 0.0149 | 0.1827 | 0.9414 | 0.078* | |
C7 | 0.1838 (5) | −0.0028 (4) | 0.8892 (3) | 0.0555 (10) | |
H7A | 0.2008 | −0.0868 | 0.9093 | 0.067* | |
H7B | 0.0882 | 0.0006 | 0.8619 | 0.067* | |
C8 | 0.4168 (4) | −0.0275 (3) | 0.8098 (3) | 0.0456 (8) | |
C9 | 0.5104 (4) | 0.0078 (3) | 0.7283 (3) | 0.0407 (8) | |
C10 | 0.4765 (4) | 0.0948 (4) | 0.6614 (3) | 0.0477 (9) | |
H10 | 0.3906 | 0.1385 | 0.6656 | 0.057* | |
C11 | 0.5694 (5) | 0.1168 (4) | 0.5888 (3) | 0.0504 (9) | |
H11 | 0.5455 | 0.1751 | 0.5439 | 0.060* | |
C12 | 0.7303 (5) | −0.0274 (5) | 0.6477 (3) | 0.0677 (13) | |
H12 | 0.8177 | −0.0686 | 0.6432 | 0.081* | |
C13 | 0.6423 (5) | −0.0514 (5) | 0.7198 (3) | 0.0627 (12) | |
H13 | 0.6700 | −0.1084 | 0.7648 | 0.075* | |
C14 | 0.7913 (5) | 0.0782 (5) | 0.5020 (3) | 0.0705 (13) | |
H14A | 0.7477 | 0.1364 | 0.4602 | 0.106* | |
H14B | 0.8087 | 0.0025 | 0.4694 | 0.106* | |
H14C | 0.8810 | 0.1107 | 0.5246 | 0.106* | |
N1 | 0.6942 (4) | 0.0555 (3) | 0.5815 (2) | 0.0494 (8) | |
N2 | 0.2902 (3) | 0.0295 (3) | 0.8172 (2) | 0.0475 (7) | |
H2 | 0.262 (7) | 0.085 (6) | 0.766 (4) | 0.12 (2)* | |
O1 | 0.4598 (4) | −0.1053 (3) | 0.86557 (19) | 0.0634 (8) | |
I1 | 0.06127 (3) | 0.22276 (3) | 0.68164 (2) | 0.05375 (9) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0396 (19) | 0.0438 (18) | 0.0435 (18) | −0.0051 (15) | 0.0082 (17) | 0.0088 (16) |
C2 | 0.0350 (19) | 0.057 (2) | 0.050 (2) | 0.0010 (16) | 0.0021 (18) | 0.0085 (19) |
C3 | 0.055 (3) | 0.075 (3) | 0.044 (2) | −0.014 (2) | 0.002 (2) | 0.003 (2) |
C4 | 0.103 (4) | 0.069 (3) | 0.050 (2) | −0.011 (3) | 0.018 (3) | −0.011 (2) |
C5 | 0.096 (4) | 0.069 (3) | 0.076 (3) | 0.033 (3) | 0.016 (3) | 0.000 (2) |
C6 | 0.059 (3) | 0.078 (3) | 0.059 (3) | 0.023 (2) | −0.002 (2) | 0.015 (2) |
C7 | 0.052 (2) | 0.063 (3) | 0.051 (2) | −0.015 (2) | 0.002 (2) | −0.0028 (19) |
C8 | 0.051 (2) | 0.0456 (19) | 0.0401 (18) | −0.0024 (16) | −0.011 (2) | −0.0033 (16) |
C9 | 0.0420 (19) | 0.042 (2) | 0.0382 (19) | −0.0002 (15) | −0.0065 (16) | −0.0043 (15) |
C10 | 0.048 (2) | 0.047 (2) | 0.048 (2) | 0.0084 (16) | −0.0015 (17) | −0.0013 (16) |
C11 | 0.054 (2) | 0.048 (2) | 0.049 (2) | 0.002 (2) | −0.004 (2) | 0.0057 (16) |
C12 | 0.046 (3) | 0.087 (4) | 0.070 (3) | 0.020 (2) | 0.002 (2) | 0.012 (3) |
C13 | 0.056 (3) | 0.076 (3) | 0.055 (2) | 0.021 (2) | −0.002 (2) | 0.018 (2) |
C14 | 0.058 (3) | 0.097 (4) | 0.057 (3) | −0.001 (3) | 0.010 (2) | 0.004 (3) |
N1 | 0.0408 (17) | 0.061 (2) | 0.0463 (17) | −0.0012 (15) | −0.0045 (15) | −0.0002 (15) |
N2 | 0.0472 (18) | 0.0553 (19) | 0.0400 (16) | 0.0010 (14) | 0.0006 (18) | −0.0012 (17) |
O1 | 0.068 (2) | 0.0664 (18) | 0.0562 (15) | 0.0077 (17) | −0.0044 (16) | 0.0181 (15) |
I1 | 0.05146 (14) | 0.05593 (15) | 0.05386 (14) | 0.01142 (12) | −0.00363 (13) | −0.00252 (12) |
C1—C6 | 1.381 (6) | C8—C9 | 1.504 (5) |
C1—C2 | 1.387 (5) | C9—C10 | 1.383 (5) |
C1—C7 | 1.500 (5) | C9—C13 | 1.389 (6) |
C2—C3 | 1.358 (6) | C10—C11 | 1.371 (5) |
C2—H1 | 0.9300 | C10—H10 | 0.9300 |
C3—C4 | 1.367 (7) | C11—N1 | 1.341 (5) |
C3—H3 | 0.9300 | C11—H11 | 0.9300 |
C4—C5 | 1.371 (7) | C12—C13 | 1.342 (6) |
C4—H4 | 0.9300 | C12—N1 | 1.349 (5) |
C5—C6 | 1.376 (7) | C12—H12 | 0.9300 |
C5—H5 | 0.9300 | C13—H13 | 0.9300 |
C6—H6 | 0.9300 | C14—N1 | 1.472 (5) |
C7—N2 | 1.469 (5) | C14—H14A | 0.9600 |
C7—H7A | 0.9700 | C14—H14B | 0.9600 |
C7—H7B | 0.9700 | C14—H14C | 0.9600 |
C8—O1 | 1.229 (4) | N2—H2 | 0.98 (6) |
C8—N2 | 1.334 (5) | ||
C6—C1—C2 | 117.7 (4) | C10—C9—C13 | 117.2 (4) |
C6—C1—C7 | 121.3 (4) | C10—C9—C8 | 125.5 (3) |
C2—C1—C7 | 121.0 (4) | C13—C9—C8 | 117.3 (4) |
C3—C2—C1 | 121.4 (4) | C11—C10—C9 | 120.0 (4) |
C3—C2—H1 | 119.3 | C11—C10—H10 | 120.0 |
C1—C2—H1 | 119.3 | C9—C10—H10 | 120.0 |
C2—C3—C4 | 120.4 (4) | N1—C11—C10 | 121.1 (4) |
C2—C3—H3 | 119.8 | N1—C11—H11 | 119.4 |
C4—C3—H3 | 119.8 | C10—C11—H11 | 119.4 |
C3—C4—C5 | 119.4 (4) | C13—C12—N1 | 121.2 (4) |
C3—C4—H4 | 120.3 | C13—C12—H12 | 119.4 |
C5—C4—H4 | 120.3 | N1—C12—H12 | 119.4 |
C4—C5—C6 | 120.4 (4) | C12—C13—C9 | 120.9 (4) |
C4—C5—H5 | 119.8 | C12—C13—H13 | 119.5 |
C6—C5—H5 | 119.8 | C9—C13—H13 | 119.5 |
C5—C6—C1 | 120.6 (4) | N1—C14—H14A | 109.5 |
C5—C6—H6 | 119.7 | N1—C14—H14B | 109.5 |
C1—C6—H6 | 119.7 | H14A—C14—H14B | 109.5 |
N2—C7—C1 | 113.2 (3) | N1—C14—H14C | 109.5 |
N2—C7—H7A | 108.9 | H14A—C14—H14C | 109.5 |
C1—C7—H7A | 108.9 | H14B—C14—H14C | 109.5 |
N2—C7—H7B | 108.9 | C11—N1—C12 | 119.4 (4) |
C1—C7—H7B | 108.9 | C11—N1—C14 | 120.4 (3) |
H7A—C7—H7B | 107.8 | C12—N1—C14 | 120.2 (4) |
O1—C8—N2 | 123.7 (4) | C8—N2—C7 | 122.5 (4) |
O1—C8—C9 | 119.4 (4) | C8—N2—H2 | 118 (4) |
N2—C8—C9 | 116.9 (3) | C7—N2—H2 | 119 (4) |
C6—C1—C2—C3 | −0.6 (6) | C13—C9—C10—C11 | 2.1 (6) |
C7—C1—C2—C3 | −179.3 (4) | C8—C9—C10—C11 | −178.4 (3) |
C1—C2—C3—C4 | 0.3 (6) | C9—C10—C11—N1 | −0.4 (6) |
C2—C3—C4—C5 | 0.6 (7) | N1—C12—C13—C9 | 0.5 (8) |
C3—C4—C5—C6 | −1.2 (8) | C10—C9—C13—C12 | −2.2 (7) |
C4—C5—C6—C1 | 0.9 (8) | C8—C9—C13—C12 | 178.2 (4) |
C2—C1—C6—C5 | 0.0 (6) | C10—C11—N1—C12 | −1.4 (6) |
C7—C1—C6—C5 | 178.7 (4) | C10—C11—N1—C14 | 178.7 (4) |
C6—C1—C7—N2 | 103.1 (4) | C13—C12—N1—C11 | 1.3 (7) |
C2—C1—C7—N2 | −78.2 (5) | C13—C12—N1—C14 | −178.7 (5) |
O1—C8—C9—C10 | −179.0 (4) | O1—C8—N2—C7 | −5.2 (6) |
N2—C8—C9—C10 | 0.6 (5) | C9—C8—N2—C7 | 175.1 (3) |
O1—C8—C9—C13 | 0.5 (5) | C1—C7—N2—C8 | 97.8 (4) |
N2—C8—C9—C13 | −179.8 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2···I1 | 0.98 (6) | 2.68 (6) | 3.563 (3) | 150 (5) |
C14—H14A···I1i | 0.96 | 3.08 | 4.018 (5) | 168 |
C14—H14C···I1ii | 0.96 | 3.06 | 3.919 (5) | 150 |
Symmetry codes: (i) x+1/2, −y+1/2, −z+1; (ii) x+1, y, z. |
Acknowledgements
We thank Dr E. A. Losev for recording the FT–IR ATR spectra.
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