organic compounds
3-Ethyl-3-hydroxy-8-methoxyquinoline-2,4(1H,3H)-dione monohydrate
aDepartment of Chemistry, Faculty of Technology, Tomas Bata University in Zlin, Zlin 76272, Czech Republic, and bFaculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia
*Correspondence e-mail: andrej.pevec@fkkt.uni-lj.si
In the title hydrate, C12H13NO4·H2O, the piperidine ring that is fused to the benzene ring is in a sofa conformation with the chiral C atom lying 0.4084 (18) Å out of the plane of the nine fused-ring atoms. In the crystal, O—H⋯O and N—H⋯O hydrogen bonds link the organic molecules and water molecules into chains running along the b-axis direction. The chains are further connected into layers parallel to the bc plane by π–π interactions between inversion-related benzene rings [centroid–centroid distance = 3.8846 (9) Å].
Related literature
For methods of preparation of 3-alkyl- or 3-aryl-3-hydroxyquinoline-2,4-diones by oxidation of the corresponding 3-alkyl- or 3-arylquinolin-2-ones, see: Stadlbauer & Kappe (1982); Stadlbauer et al. (1992). For naturally occurring 3-hydroxyquinoline-2,4-diones, see: Neuenhaus & Budzikiewicz (1979); Luo et al. (2009). For the biological activity of 3-hydroxyquinoline-2,4-diones, see: Prisyazhnyuk et al. (1984); Luo et al. (2009). For a related structure, see: Kafka et al. (2012).
Experimental
Crystal data
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Refinement
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Data collection: COLLECT (Nonius, 1998); cell DENZO and SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999).
Supporting information
10.1107/S1600536812043280/tk5162sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812043280/tk5162Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812043280/tk5162Isup3.cml
To a solution of 3-ethyl-4-hydroxy-8-methoxyquinolin-2(1H)-one (4.38 g, 20.0 mmol) in 0.5 M sodium hydroxide (120 ml), 30% peroxyacetic acid in acetic acid (6.7 ml, 30 mmol) was added drop-wise within 30 min under stirring at room temperature. After several minutes a precipitate started to form. The reaction mixture was stirred for additional 30 min and then left at 10 °C overnight. The solid phase was filtered off under suction, dispersed in 5% aqueous sodium bicarbonate solution (25 ml), filtered off and washed with water (3 x 20 ml). Crystallization of the above air-dried solid from toluene afforded 3.92 g (83%) of the final product (I), M.pt 371–372 K.
The N-bonded hydrogen atom was located in a difference map and refined with the using distance restraint with N—H = 0.86±0.02 Å and with Uiso(H) = 1.2Ueq(N). Water H atoms were located in a difference map and refined with Uiso(H) = 1.2Ueq(O). The O—H distance of water were restrained to be 0.96±0.02 Å. All other H atoms were included in the model at geometrically calculated positions and refined using a riding model, with C—H bond lengths constrained to 0.93 Å (aromatic H), 0.96 Å (methyl H), 0.97 Å (methylene H) and O—H = 0.82 Å, and with Uiso(H) values of 1.2Ueq(C) [for aromatic and methylene H] or 1.5Ueq(C) [for oxygen and methyl H].
Data collection: COLLECT (Nonius, 1998); cell
DENZO and SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999).C12H13NO4·H2O | Dx = 1.388 Mg m−3 |
Mr = 253.25 | Melting point = 371–372 K |
Orthorhombic, Pbca | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2ab | Cell parameters from 3161 reflections |
a = 16.5055 (4) Å | θ = 1.0–27.5° |
b = 8.8068 (2) Å | µ = 0.11 mm−1 |
c = 16.6690 (4) Å | T = 293 K |
V = 2423.02 (10) Å3 | Prism, yellow |
Z = 8 | 0.50 × 0.25 × 0.20 mm |
F(000) = 1072 |
Nonius KappaCCD area-detector diffractometer | 2779 independent reflections |
Radiation source: fine-focus sealed tube | 1963 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.019 |
ϕ scans + ω scans | θmax = 27.5°, θmin = 3.4° |
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997) | h = −21→21 |
Tmin = 0.948, Tmax = 0.979 | k = −11→11 |
5200 measured reflections | l = −21→21 |
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)] = 0.044 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.127 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0662P)2 + 0.4669P] where P = (Fo2 + 2Fc2)/3 |
2779 reflections | (Δ/σ)max = 0.0001 |
175 parameters | Δρmax = 0.26 e Å−3 |
3 restraints | Δρmin = −0.23 e Å−3 |
C12H13NO4·H2O | V = 2423.02 (10) Å3 |
Mr = 253.25 | Z = 8 |
Orthorhombic, Pbca | Mo Kα radiation |
a = 16.5055 (4) Å | µ = 0.11 mm−1 |
b = 8.8068 (2) Å | T = 293 K |
c = 16.6690 (4) Å | 0.50 × 0.25 × 0.20 mm |
Nonius KappaCCD area-detector diffractometer | 2779 independent reflections |
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997) | 1963 reflections with I > 2σ(I) |
Tmin = 0.948, Tmax = 0.979 | Rint = 0.019 |
5200 measured reflections |
R[F2 > 2σ(F2)] = 0.044 | 3 restraints |
wR(F2) = 0.127 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.26 e Å−3 |
2779 reflections | Δρmin = −0.23 e Å−3 |
175 parameters |
Experimental. 211 frames in 4 sets of ϕ scans + ω scans. Rotation/frame = 2 °. Crystal-detector distance = 31 mm. Measuring time = 20 s/°. |
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. |
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 > 2σ(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 | 0.08014 (8) | 0.56475 (12) | 0.75104 (6) | 0.0505 (3) | |
O2 | 0.04557 (8) | 0.18242 (13) | 0.56925 (8) | 0.0576 (4) | |
O3 | 0.05871 (8) | 0.26982 (13) | 0.72594 (7) | 0.0527 (3) | |
H3 | 0.0359 | 0.1965 | 0.7058 | 0.079* | |
O4 | 0.14902 (8) | 0.81485 (13) | 0.51080 (7) | 0.0542 (3) | |
N1 | 0.11348 (8) | 0.61105 (15) | 0.62211 (7) | 0.0395 (3) | |
H1N | 0.1065 (10) | 0.7068 (16) | 0.6299 (11) | 0.047* | |
C1 | 0.09586 (9) | 0.51728 (17) | 0.68405 (8) | 0.0374 (3) | |
C2 | 0.10269 (9) | 0.34757 (17) | 0.66669 (9) | 0.0392 (4) | |
C3 | 0.07607 (9) | 0.30617 (16) | 0.58203 (10) | 0.0408 (4) | |
C4 | 0.09477 (9) | 0.41692 (17) | 0.51912 (9) | 0.0381 (3) | |
C5 | 0.09051 (10) | 0.3782 (2) | 0.43780 (10) | 0.0481 (4) | |
H5 | 0.0777 | 0.2795 | 0.4227 | 0.058* | |
C6 | 0.10534 (11) | 0.4863 (2) | 0.38047 (10) | 0.0527 (4) | |
H6 | 0.1023 | 0.4608 | 0.3264 | 0.063* | |
C7 | 0.12485 (10) | 0.6336 (2) | 0.40285 (9) | 0.0492 (4) | |
H7 | 0.1344 | 0.7062 | 0.3634 | 0.059* | |
C8 | 0.13022 (9) | 0.67423 (18) | 0.48253 (9) | 0.0410 (4) | |
C9 | 0.11398 (9) | 0.56549 (17) | 0.54186 (8) | 0.0358 (3) | |
C10 | 0.19372 (10) | 0.3023 (2) | 0.67026 (10) | 0.0523 (4) | |
H10A | 0.1986 | 0.1950 | 0.6581 | 0.063* | |
H10B | 0.2228 | 0.3579 | 0.6291 | 0.063* | |
C11 | 0.23315 (12) | 0.3326 (3) | 0.74990 (11) | 0.0683 (6) | |
H11A | 0.2035 | 0.2817 | 0.7915 | 0.102* | |
H11B | 0.2333 | 0.4399 | 0.7602 | 0.102* | |
H11C | 0.2879 | 0.2957 | 0.7490 | 0.102* | |
C12 | 0.16490 (14) | 0.9320 (2) | 0.45424 (12) | 0.0670 (6) | |
H12A | 0.1179 | 0.9477 | 0.4214 | 0.101* | |
H12B | 0.2099 | 0.9033 | 0.4210 | 0.101* | |
H12C | 0.1777 | 1.0243 | 0.4822 | 0.101* | |
O1W | 0.06321 (11) | 0.90745 (16) | 0.66799 (10) | 0.0752 (5) | |
H1W | 0.0478 (14) | 0.978 (3) | 0.6301 (13) | 0.090* | |
H2W | 0.0132 (11) | 0.900 (3) | 0.6914 (14) | 0.090* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0709 (8) | 0.0477 (7) | 0.0329 (6) | 0.0008 (5) | 0.0073 (5) | −0.0009 (5) |
O2 | 0.0692 (8) | 0.0379 (6) | 0.0657 (8) | −0.0052 (5) | −0.0121 (6) | −0.0034 (5) |
O3 | 0.0674 (8) | 0.0436 (6) | 0.0472 (7) | −0.0100 (6) | 0.0055 (6) | 0.0084 (5) |
O4 | 0.0786 (9) | 0.0454 (6) | 0.0386 (6) | −0.0116 (6) | 0.0060 (6) | 0.0066 (5) |
N1 | 0.0543 (8) | 0.0341 (6) | 0.0301 (6) | −0.0024 (5) | 0.0009 (5) | −0.0008 (5) |
C1 | 0.0403 (8) | 0.0402 (8) | 0.0318 (7) | 0.0000 (6) | 0.0002 (6) | 0.0013 (6) |
C2 | 0.0440 (8) | 0.0380 (8) | 0.0357 (8) | 0.0022 (6) | 0.0002 (6) | 0.0046 (6) |
C3 | 0.0398 (8) | 0.0368 (8) | 0.0457 (9) | 0.0065 (6) | −0.0034 (7) | −0.0034 (6) |
C4 | 0.0369 (7) | 0.0427 (8) | 0.0346 (7) | 0.0054 (6) | −0.0030 (6) | −0.0040 (6) |
C5 | 0.0512 (9) | 0.0533 (10) | 0.0399 (9) | 0.0082 (8) | −0.0058 (7) | −0.0118 (7) |
C6 | 0.0588 (10) | 0.0682 (11) | 0.0312 (8) | 0.0108 (9) | −0.0013 (7) | −0.0079 (8) |
C7 | 0.0531 (9) | 0.0626 (11) | 0.0319 (8) | 0.0079 (8) | 0.0049 (7) | 0.0053 (7) |
C8 | 0.0429 (8) | 0.0451 (9) | 0.0349 (8) | 0.0033 (6) | 0.0040 (6) | 0.0024 (7) |
C9 | 0.0360 (7) | 0.0418 (8) | 0.0295 (7) | 0.0037 (6) | −0.0001 (6) | 0.0000 (6) |
C10 | 0.0496 (9) | 0.0584 (10) | 0.0490 (10) | 0.0130 (8) | −0.0069 (8) | 0.0009 (8) |
C11 | 0.0583 (11) | 0.0913 (16) | 0.0553 (11) | 0.0106 (11) | −0.0155 (9) | −0.0012 (10) |
C12 | 0.0872 (15) | 0.0552 (11) | 0.0587 (12) | −0.0077 (10) | 0.0127 (10) | 0.0164 (9) |
O1W | 0.0992 (11) | 0.0548 (8) | 0.0715 (10) | 0.0047 (8) | 0.0365 (9) | 0.0061 (7) |
O1—C1 | 1.2202 (17) | C6—C7 | 1.388 (3) |
O2—C3 | 1.2193 (19) | C6—H6 | 0.9300 |
O3—C2 | 1.4040 (18) | C7—C8 | 1.378 (2) |
O3—H3 | 0.8200 | C7—H7 | 0.9300 |
O4—C8 | 1.361 (2) | C8—C9 | 1.402 (2) |
O4—C12 | 1.422 (2) | C10—C11 | 1.502 (2) |
N1—C1 | 1.3537 (19) | C10—H10A | 0.9700 |
N1—C9 | 1.3966 (18) | C10—H10B | 0.9700 |
N1—H1N | 0.861 (14) | C11—H11A | 0.9600 |
C1—C2 | 1.527 (2) | C11—H11B | 0.9600 |
C2—C3 | 1.522 (2) | C11—H11C | 0.9600 |
C2—C10 | 1.555 (2) | C12—H12A | 0.9600 |
C3—C4 | 1.465 (2) | C12—H12B | 0.9600 |
C4—C9 | 1.399 (2) | C12—H12C | 0.9600 |
C4—C5 | 1.399 (2) | O1W—H1W | 0.923 (16) |
C5—C6 | 1.371 (3) | O1W—H2W | 0.916 (16) |
C5—H5 | 0.9300 | ||
C2—O3—H3 | 109.5 | C8—C7—H7 | 119.5 |
C8—O4—C12 | 118.23 (14) | C6—C7—H7 | 119.5 |
C1—N1—C9 | 123.82 (13) | O4—C8—C7 | 125.75 (15) |
C1—N1—H1N | 117.0 (12) | O4—C8—C9 | 114.89 (13) |
C9—N1—H1N | 115.2 (12) | C7—C8—C9 | 119.34 (15) |
O1—C1—N1 | 122.32 (14) | N1—C9—C4 | 121.80 (13) |
O1—C1—C2 | 121.64 (13) | N1—C9—C8 | 118.71 (13) |
N1—C1—C2 | 115.90 (12) | C4—C9—C8 | 119.41 (13) |
O3—C2—C3 | 112.71 (13) | C11—C10—C2 | 114.01 (15) |
O3—C2—C1 | 107.81 (12) | C11—C10—H10A | 108.8 |
C3—C2—C1 | 112.89 (12) | C2—C10—H10A | 108.8 |
O3—C2—C10 | 110.35 (13) | C11—C10—H10B | 108.8 |
C3—C2—C10 | 104.65 (12) | C2—C10—H10B | 108.8 |
C1—C2—C10 | 108.35 (13) | H10A—C10—H10B | 107.6 |
O2—C3—C4 | 123.84 (15) | C10—C11—H11A | 109.5 |
O2—C3—C2 | 119.69 (14) | C10—C11—H11B | 109.5 |
C4—C3—C2 | 116.32 (13) | H11A—C11—H11B | 109.5 |
C9—C4—C5 | 120.10 (14) | C10—C11—H11C | 109.5 |
C9—C4—C3 | 118.46 (13) | H11A—C11—H11C | 109.5 |
C5—C4—C3 | 121.38 (14) | H11B—C11—H11C | 109.5 |
C6—C5—C4 | 119.83 (16) | O4—C12—H12A | 109.5 |
C6—C5—H5 | 120.1 | O4—C12—H12B | 109.5 |
C4—C5—H5 | 120.1 | H12A—C12—H12B | 109.5 |
C5—C6—C7 | 120.20 (15) | O4—C12—H12C | 109.5 |
C5—C6—H6 | 119.9 | H12A—C12—H12C | 109.5 |
C7—C6—H6 | 119.9 | H12B—C12—H12C | 109.5 |
C8—C7—C6 | 121.09 (16) | H1W—O1W—H2W | 95 (2) |
C9—N1—C1—O1 | −165.15 (15) | C4—C5—C6—C7 | 0.2 (2) |
C9—N1—C1—C2 | 19.1 (2) | C5—C6—C7—C8 | 0.4 (3) |
O1—C1—C2—O3 | 22.8 (2) | C12—O4—C8—C7 | −0.1 (3) |
N1—C1—C2—O3 | −161.35 (13) | C12—O4—C8—C9 | −178.93 (16) |
O1—C1—C2—C3 | 147.98 (15) | C6—C7—C8—O4 | 179.85 (16) |
N1—C1—C2—C3 | −36.19 (18) | C6—C7—C8—C9 | −1.4 (2) |
O1—C1—C2—C10 | −96.60 (17) | C1—N1—C9—C4 | 0.9 (2) |
N1—C1—C2—C10 | 79.22 (16) | C1—N1—C9—C8 | 177.65 (14) |
O3—C2—C3—O2 | −26.4 (2) | C5—C4—C9—N1 | 175.61 (14) |
C1—C2—C3—O2 | −148.87 (14) | C3—C4—C9—N1 | −1.8 (2) |
C10—C2—C3—O2 | 93.51 (17) | C5—C4—C9—C8 | −1.1 (2) |
O3—C2—C3—C4 | 157.87 (13) | C3—C4—C9—C8 | −178.52 (14) |
C1—C2—C3—C4 | 35.42 (18) | O4—C8—C9—N1 | 3.8 (2) |
C10—C2—C3—C4 | −82.20 (16) | C7—C8—C9—N1 | −175.08 (14) |
O2—C3—C4—C9 | 167.10 (15) | O4—C8—C9—C4 | −179.40 (14) |
C2—C3—C4—C9 | −17.4 (2) | C7—C8—C9—C4 | 1.7 (2) |
O2—C3—C4—C5 | −10.3 (2) | O3—C2—C10—C11 | −58.1 (2) |
C2—C3—C4—C5 | 165.20 (14) | C3—C2—C10—C11 | −179.62 (16) |
C9—C4—C5—C6 | 0.1 (2) | C1—C2—C10—C11 | 59.70 (19) |
C3—C4—C5—C6 | 177.47 (15) |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3···O1i | 0.82 | 2.35 | 2.9430 (17) | 130 |
N1—H1N···O1W | 0.86 (1) | 2.01 (2) | 2.8438 (19) | 163 (2) |
O1W—H1W···O2ii | 0.92 (2) | 2.07 (2) | 2.9425 (19) | 158 (2) |
O1W—H2W···O3iii | 0.92 (2) | 2.15 (2) | 2.9401 (19) | 144 (2) |
Symmetry codes: (i) −x, y−1/2, −z+3/2; (ii) x, y+1, z; (iii) −x, y+1/2, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | C12H13NO4·H2O |
Mr | 253.25 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 293 |
a, b, c (Å) | 16.5055 (4), 8.8068 (2), 16.6690 (4) |
V (Å3) | 2423.02 (10) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.11 |
Crystal size (mm) | 0.50 × 0.25 × 0.20 |
Data collection | |
Diffractometer | Nonius KappaCCD area-detector diffractometer |
Absorption correction | Multi-scan (SCALEPACK; Otwinowski & Minor, 1997) |
Tmin, Tmax | 0.948, 0.979 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5200, 2779, 1963 |
Rint | 0.019 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.044, 0.127, 1.03 |
No. of reflections | 2779 |
No. of parameters | 175 |
No. of restraints | 3 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.26, −0.23 |
Computer programs: COLLECT (Nonius, 1998), DENZO and SCALEPACK (Otwinowski & Minor, 1997), SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009) and DIAMOND (Brandenburg, 1999), WinGX (Farrugia, 1999).
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3···O1i | 0.82 | 2.35 | 2.9430 (17) | 130 |
N1—H1N···O1W | 0.861 (14) | 2.009 (15) | 2.8438 (19) | 163.1 (17) |
O1W—H1W···O2ii | 0.923 (16) | 2.065 (19) | 2.9425 (19) | 158 (2) |
O1W—H2W···O3iii | 0.916 (16) | 2.15 (2) | 2.9401 (19) | 144 (2) |
Symmetry codes: (i) −x, y−1/2, −z+3/2; (ii) x, y+1, z; (iii) −x, y+1/2, −z+3/2. |
Acknowledgements
This study was supported by the internal grant of TBU in Zlin (No. IGA/FT/2012/043), funded from the resources of specific university research, and the Slovenian Research Agency (Project P1–0230–0103 and Joint Project BI–CZ/07–08–018). This work was also partly supported through the infrastructure of the EN-FIST Centre of Excellence, Ljubljana.
References
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3-Alkyl- and 3-aryl-3-hydroxyquinoline-2,4-diones have been prepared by oxidation of the corresponding 3-alkyl- or 3-arylquinolin-2-ones by means of oxygen under UV irradiation (Stadlbauer & Kappe, 1982), m-chloroperoxybenzoic acid (Stadlbauer & Kappe, 1982), hydrogen peroxide (Stadlbauer & Kappe, 1982), nitric acid (Stadlbauer et al., 1992), or peracetic acid (Stadlbauer et al., 1992). Several 3-hydroxyquinoline-2,4-diones were isolated from bacteria Pseudomonas aeruginosa (Neuenhaus & Budzikiewicz, 1979) and from stem bark of Micromelum falcatum (Luo et al., 2009). Biological activity of several 3-hydroxyquinoline-2,4-diones has been investigated (Prisyazhnyuk et al., 1984; Luo et al., 2009). 3-Alkyl- and 3-aryl-3-hydroxyquinoline-2,4-diones are important synthetic intermediates for the preparation of new types of heterocyclic compounds.
The asymmetric unit of the title compound (I) consists of a single 3-ethyl-3-hydroxy-8-methoxyquinoline-2,4(1H,3H)-dione molecule and solvated water molecule (Fig. 1). The piperidine ring that is fused to the benzene ring has a sofa shape with chiral carbon center 0.4084 (18) Å out of the plane for 9 ring atoms. In the crystal packing organic molecules and solvated water molecules are connected by two intermolecular O—H···O and one N—H···O hydrogen bonds. These connections altogether with additional O—H···O hydrogen bonding between hydroxyl and carbonyl groups (Table 1) form linear chain running along the b axis. Non–covalent π–π interactions occur between inversion–related benzene rings [centroid–centroid distance = 3.8846 (9) Å], which stabilize the crystal packing and connect the chains into a two-dimensional supramolecular layer parallel to the bc plane (Fig. 2).