organic compounds
1-(4-Hydroxyphenyl)-3-(3,4,5-trimethoxyphenyl)thiourea
aDepartment of Chemistry, Chungnam National University, Daejeon 305-764, Republic of Korea, and bDepartment of Food Science and Technology, Chungnam National University, Daejeon 305-764, Republic of Korea
*Correspondence e-mail: skkang@cnu.ac.kr
In the title compound, C16H18N2O4S, the dihedral angle between the hydroxyphenyl ring and the plane of the thiourea moiety is 54.53 (8)°. The H atoms of the NH groups of thiourea are positioned anti to each other. In the crystal, intermolecular N—H⋯S, N—H⋯O, and O—H⋯S hydrogen bonds link the molecules into a three-dimensional network.
Related literature
For general background to tyrosinase, see: Ha et al. (2007); Kubo et al. (2000). For the development of tyrosinase inhibitors, see: Kojima et al. (1995); Cabanes et al. (1994); Casanola-Martin et al. (2006); Son et al. (2000); Iida et al. (1995). For thiourea derivatives, see: Thanigaimalai et al. (2010); Klabunde et al. (1998); Criton (2006); Daniel (2006); Yi et al. (2009); Liu et al. (2009).
Experimental
Crystal data
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Data collection
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Refinement
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Data collection: SMART (Bruker, 2002); cell SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2010); software used to prepare material for publication: WinGX (Farrugia, 1999).
Supporting information
https://doi.org/10.1107/S160053681004866X/bt5417sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S160053681004866X/bt5417Isup2.hkl
The 3,4,5-trimethoxyphenyl thiocyanate and 4-aminophenol were purchased from Sigma Chemical Co. Solvents used for organic synthesis were redistilled before use. All other chemicals and solvents were of analytical grade and were used without further purification. The title compound, (I), was prepared from the reaction of 3,4,5-trimethoxyphenyl isothiocyanate (0.20 g, 0.89 mmol) with 4-aminophenol (0.10 g, 1.10 mmol) in acetonitrile (6 ml). The reaction was completed within 30 min at room temperature. The reaction mixture was filtered rapidly and washed with n-hexane. Removal of the solvent gave a white solid (66% m.p. 499 K). Single crystals were obtained by slow evaporation of the ethanol at room temperature.
The H atoms of the NH and OH groups were located in a difference Fourier map and refined freely. The remaining H atoms were positioned geometrically and refined using a riding model with C—H = 0.93–0.96 Å, and with Uiso(H) = 1.2Ueq (C) for aromatic and 1.5Ueq(C) for methyl H atoms.
Melanin production is primary responsible for the skin color, and melanin plays a key role in protecting human skin from the harmful UV-induced skin damages. Tyrosinase is the key enzyme (Ha et al., 2007; Kubo et al., 2000)) that converts tyrosine to melanin and its inhibitors are the target molecules to develop and research anti-pigmentation agents for the application to skin care. Numerous potential tyrosinase inhibitors have been discovered from natural and synthetic sources, such as ascorbic acid (Kojima et al., 1995), kojic acid (Cabanes et al., 1994), arbutin (Casanola-Martin et al., 2006) and tropolone (Son et al., 2000; Iida et al., 1995). Some thiourea derivatives, such as phenylthiourea (Thanigaimalai et al., 2010; Klabunde et al., 1998; Criton, 2006), alkylthiourea (Daniel, 2006), thiosemicarbazone (Yi et al., 2009) and thiosemicarbazide (Liu et al., 2009) have been also reported. During our works on developing potent whitening agents preventing the inadequacies of current whitening agents (poor skin penetration and toxicity) and minimizing the inhibitory effects of melanin creation, we have synthesized the title compound from the reaction of 3,4,5-trimethoxyphenyl isothiocyanate and 4-aminophenol under ambient condition.
The 3,4,5-trimethoxyphenyl moiety is almost planar with r.m.s. deviation of 0.050 Å from the corresponding least-squares plane defined by the ten constituent atoms. The dihedral angle between the phenyl ring and the plane of thiourea moiety is 54.53 (8) °. In the crystal, intermolecular N—H···S, N—H···O, and O—H···S hydrogen bonds link the molecules into a three-dimensional network (Fig. 2, Table 1). The H atoms of the NH groups of thiourea are positioned anti to each other.
For general background to tyrosinase, see: Ha et al. (2007); Kubo et al. (2000). For the development of tyrosinase inhibitors, see: Kojima et al. (1995); Cabanes et al. (1994); Casanola-Martin et al. (2006); Son et al. (2000); Iida et al. (1995). For thiourea derivatives, see: Thanigaimalai et al. (2010); Klabunde et al. (1998); Criton (2006); Daniel (2006); Yi et al. (2009); Liu et al. (2009).
Data collection: SMART (Bruker, 2002); cell
SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2010); software used to prepare material for publication: WinGX (Farrugia, 1999).C16H18N2O4S | F(000) = 704 |
Mr = 334.38 | Dx = 1.338 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 2485 reflections |
a = 10.5705 (5) Å | θ = 2.5–24.0° |
b = 12.8195 (7) Å | µ = 0.22 mm−1 |
c = 12.4157 (7) Å | T = 296 K |
β = 99.434 (3)° | Plate, colourless |
V = 1659.68 (15) Å3 | 0.15 × 0.08 × 0.03 mm |
Z = 4 |
Bruker SMART CCD area-detector diffractometer | Rint = 0.050 |
φ and ω scans | θmax = 26°, θmin = 2.0° |
12193 measured reflections | h = −13→8 |
3166 independent reflections | k = −15→8 |
1723 reflections with I > 2σ(I) | l = −12→15 |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.045 | w = 1/[σ2(Fo2) + (0.0578P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.121 | (Δ/σ)max < 0.001 |
S = 0.94 | Δρmax = 0.50 e Å−3 |
3166 reflections | Δρmin = −0.27 e Å−3 |
219 parameters |
C16H18N2O4S | V = 1659.68 (15) Å3 |
Mr = 334.38 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 10.5705 (5) Å | µ = 0.22 mm−1 |
b = 12.8195 (7) Å | T = 296 K |
c = 12.4157 (7) Å | 0.15 × 0.08 × 0.03 mm |
β = 99.434 (3)° |
Bruker SMART CCD area-detector diffractometer | 1723 reflections with I > 2σ(I) |
12193 measured reflections | Rint = 0.050 |
3166 independent reflections |
R[F2 > 2σ(F2)] = 0.045 | 0 restraints |
wR(F2) = 0.121 | H atoms treated by a mixture of independent and constrained refinement |
S = 0.94 | Δρmax = 0.50 e Å−3 |
3166 reflections | Δρmin = −0.27 e Å−3 |
219 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.2918 (2) | 0.0884 (2) | 0.50738 (19) | 0.0393 (6) | |
C2 | 0.3504 (2) | 0.1779 (2) | 0.4769 (2) | 0.0418 (6) | |
H2 | 0.3075 | 0.2214 | 0.4229 | 0.05* | |
C3 | 0.4737 (2) | 0.2018 (2) | 0.5278 (2) | 0.0433 (7) | |
C4 | 0.5374 (2) | 0.1378 (2) | 0.6101 (2) | 0.0460 (7) | |
C5 | 0.4764 (2) | 0.04838 (19) | 0.63858 (19) | 0.0373 (6) | |
C6 | 0.3541 (2) | 0.0237 (2) | 0.5875 (2) | 0.0397 (6) | |
H6 | 0.314 | −0.0364 | 0.6071 | 0.048* | |
N7 | 0.1622 (2) | 0.06459 (18) | 0.4621 (2) | 0.0459 (6) | |
H7 | 0.119 (2) | 0.045 (2) | 0.507 (2) | 0.055 (9)* | |
C8 | 0.1061 (2) | 0.06515 (19) | 0.3571 (2) | 0.0410 (6) | |
S9 | −0.05561 (6) | 0.05352 (6) | 0.32614 (6) | 0.0539 (3) | |
N10 | 0.1831 (2) | 0.0730 (2) | 0.28268 (18) | 0.0489 (7) | |
H10 | 0.259 (2) | 0.0614 (19) | 0.302 (2) | 0.051 (8)* | |
C11 | 0.1464 (2) | 0.0882 (2) | 0.1678 (2) | 0.0420 (7) | |
C12 | 0.1835 (2) | 0.0159 (2) | 0.0971 (2) | 0.0486 (7) | |
H12 | 0.2269 | −0.0441 | 0.1241 | 0.058* | |
C13 | 0.1559 (2) | 0.0330 (2) | −0.0148 (2) | 0.0492 (7) | |
H13 | 0.1821 | −0.015 | −0.0629 | 0.059* | |
C14 | 0.0900 (3) | 0.1207 (2) | −0.0543 (2) | 0.0505 (7) | |
C15 | 0.0518 (3) | 0.1923 (2) | 0.0164 (2) | 0.0548 (8) | |
H15 | 0.006 | 0.2512 | −0.0107 | 0.066* | |
C16 | 0.0815 (2) | 0.1766 (2) | 0.1278 (2) | 0.0501 (7) | |
H16 | 0.0577 | 0.2259 | 0.1757 | 0.06* | |
O17 | 0.0601 (2) | 0.14204 (17) | −0.16395 (17) | 0.0751 (7) | |
H17 | 0.067 (3) | 0.083 (3) | −0.211 (3) | 0.113* | |
O18 | 0.53853 (18) | 0.28931 (15) | 0.50440 (16) | 0.0652 (6) | |
C19 | 0.4781 (3) | 0.3585 (2) | 0.4229 (3) | 0.0756 (10) | |
H19A | 0.5348 | 0.4155 | 0.4151 | 0.113* | |
H19B | 0.4006 | 0.3849 | 0.4437 | 0.113* | |
H19C | 0.458 | 0.322 | 0.3547 | 0.113* | |
O20 | 0.6530 (2) | 0.1626 (2) | 0.67179 (19) | 0.0943 (8) | |
C21 | 0.7566 (3) | 0.1977 (3) | 0.6305 (4) | 0.1032 (14) | |
H21A | 0.8255 | 0.2117 | 0.6892 | 0.155* | |
H21B | 0.7343 | 0.2606 | 0.5898 | 0.155* | |
H21C | 0.783 | 0.1457 | 0.5832 | 0.155* | |
O22 | 0.54582 (15) | −0.01140 (14) | 0.71848 (14) | 0.0501 (5) | |
C23 | 0.4836 (3) | −0.0992 (2) | 0.7567 (2) | 0.0669 (9) | |
H23A | 0.5424 | −0.1348 | 0.8117 | 0.1* | |
H23B | 0.456 | −0.1458 | 0.6969 | 0.1* | |
H23C | 0.4106 | −0.0761 | 0.7871 | 0.1* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0324 (13) | 0.0531 (16) | 0.0315 (16) | −0.0018 (13) | 0.0026 (12) | −0.0023 (13) |
C2 | 0.0410 (15) | 0.0485 (16) | 0.0356 (16) | 0.0011 (14) | 0.0058 (13) | 0.0035 (12) |
C3 | 0.0436 (15) | 0.0451 (16) | 0.0428 (17) | −0.0060 (14) | 0.0114 (14) | −0.0013 (14) |
C4 | 0.0330 (14) | 0.0615 (18) | 0.0408 (17) | −0.0099 (14) | −0.0024 (13) | −0.0017 (14) |
C5 | 0.0342 (13) | 0.0489 (16) | 0.0289 (15) | 0.0021 (13) | 0.0054 (12) | 0.0002 (12) |
C6 | 0.0350 (14) | 0.0475 (15) | 0.0368 (16) | −0.0040 (13) | 0.0061 (12) | 0.0015 (12) |
N7 | 0.0326 (12) | 0.0695 (17) | 0.0347 (15) | −0.0071 (12) | 0.0027 (12) | 0.0069 (12) |
C8 | 0.0348 (13) | 0.0508 (16) | 0.0358 (17) | −0.0001 (13) | 0.0008 (13) | 0.0021 (13) |
S9 | 0.0326 (4) | 0.0859 (6) | 0.0421 (5) | −0.0061 (4) | 0.0031 (3) | 0.0022 (4) |
N10 | 0.0282 (12) | 0.0802 (18) | 0.0378 (16) | 0.0027 (13) | 0.0036 (11) | 0.0030 (12) |
C11 | 0.0302 (13) | 0.0629 (18) | 0.0328 (17) | −0.0070 (13) | 0.0050 (12) | 0.0018 (14) |
C12 | 0.0377 (15) | 0.0613 (18) | 0.0468 (19) | 0.0016 (14) | 0.0074 (14) | 0.0023 (15) |
C13 | 0.0494 (16) | 0.0583 (18) | 0.0414 (19) | −0.0069 (15) | 0.0120 (14) | −0.0037 (14) |
C14 | 0.0537 (17) | 0.0601 (19) | 0.0368 (18) | −0.0173 (16) | 0.0043 (15) | 0.0055 (15) |
C15 | 0.0609 (18) | 0.0531 (18) | 0.050 (2) | −0.0024 (15) | 0.0070 (16) | 0.0067 (15) |
C16 | 0.0483 (16) | 0.0567 (18) | 0.045 (2) | −0.0036 (15) | 0.0070 (14) | −0.0031 (14) |
O17 | 0.1081 (19) | 0.0753 (15) | 0.0396 (14) | −0.0098 (14) | 0.0056 (13) | 0.0103 (11) |
O18 | 0.0618 (13) | 0.0624 (13) | 0.0684 (14) | −0.0216 (11) | 0.0022 (11) | 0.0138 (11) |
C19 | 0.087 (2) | 0.0554 (19) | 0.086 (3) | −0.0068 (18) | 0.020 (2) | 0.0201 (19) |
O20 | 0.0543 (14) | 0.133 (2) | 0.0873 (18) | −0.0382 (14) | −0.0146 (13) | 0.0378 (15) |
C21 | 0.049 (2) | 0.092 (3) | 0.163 (4) | −0.006 (2) | 0.001 (2) | 0.020 (3) |
O22 | 0.0386 (10) | 0.0654 (12) | 0.0443 (12) | 0.0019 (9) | 0.0011 (9) | 0.0128 (10) |
C23 | 0.0617 (19) | 0.078 (2) | 0.060 (2) | 0.0053 (18) | 0.0080 (17) | 0.0287 (17) |
C1—C6 | 1.377 (3) | C12—H12 | 0.93 |
C1—C2 | 1.386 (3) | C13—C14 | 1.371 (4) |
C1—N7 | 1.426 (3) | C13—H13 | 0.93 |
C2—C3 | 1.387 (3) | C14—O17 | 1.374 (3) |
C2—H2 | 0.93 | C14—C15 | 1.376 (4) |
C3—O18 | 1.371 (3) | C15—C16 | 1.381 (4) |
C3—C4 | 1.394 (3) | C15—H15 | 0.93 |
C4—O20 | 1.370 (3) | C16—H16 | 0.93 |
C4—C5 | 1.389 (3) | O17—H17 | 0.97 (3) |
C5—O22 | 1.368 (3) | O18—C19 | 1.416 (3) |
C5—C6 | 1.380 (3) | C19—H19A | 0.96 |
C6—H6 | 0.93 | C19—H19B | 0.96 |
N7—C8 | 1.341 (3) | C19—H19C | 0.96 |
N7—H7 | 0.81 (3) | O20—C21 | 1.360 (4) |
C8—N10 | 1.331 (3) | C21—H21A | 0.96 |
C8—S9 | 1.696 (2) | C21—H21B | 0.96 |
N10—C11 | 1.429 (3) | C21—H21C | 0.96 |
N10—H10 | 0.81 (2) | O22—C23 | 1.423 (3) |
C11—C16 | 1.375 (3) | C23—H23A | 0.96 |
C11—C12 | 1.377 (3) | C23—H23B | 0.96 |
C12—C13 | 1.389 (3) | C23—H23C | 0.96 |
C6—C1—C2 | 120.9 (2) | C14—C13—H13 | 120.1 |
C6—C1—N7 | 118.1 (2) | C12—C13—H13 | 120.1 |
C2—C1—N7 | 120.9 (2) | C13—C14—O17 | 122.6 (3) |
C1—C2—C3 | 119.1 (2) | C13—C14—C15 | 120.3 (3) |
C1—C2—H2 | 120.4 | O17—C14—C15 | 117.1 (3) |
C3—C2—H2 | 120.4 | C14—C15—C16 | 120.0 (3) |
O18—C3—C2 | 123.3 (2) | C14—C15—H15 | 120 |
O18—C3—C4 | 116.0 (2) | C16—C15—H15 | 120 |
C2—C3—C4 | 120.6 (2) | C11—C16—C15 | 120.0 (3) |
O20—C4—C5 | 117.2 (2) | C11—C16—H16 | 120 |
O20—C4—C3 | 123.5 (2) | C15—C16—H16 | 120 |
C5—C4—C3 | 118.9 (2) | C14—O17—H17 | 115 (2) |
O22—C5—C6 | 123.7 (2) | C3—O18—C19 | 118.8 (2) |
O22—C5—C4 | 115.5 (2) | O18—C19—H19A | 109.5 |
C6—C5—C4 | 120.7 (2) | O18—C19—H19B | 109.5 |
C1—C6—C5 | 119.7 (2) | H19A—C19—H19B | 109.5 |
C1—C6—H6 | 120.2 | O18—C19—H19C | 109.5 |
C5—C6—H6 | 120.2 | H19A—C19—H19C | 109.5 |
C8—N7—C1 | 128.7 (2) | H19B—C19—H19C | 109.5 |
C8—N7—H7 | 117.2 (19) | C21—O20—C4 | 124.5 (3) |
C1—N7—H7 | 113.9 (18) | O20—C21—H21A | 109.5 |
N10—C8—N7 | 116.9 (2) | O20—C21—H21B | 109.5 |
N10—C8—S9 | 123.9 (2) | H21A—C21—H21B | 109.5 |
N7—C8—S9 | 119.23 (19) | O20—C21—H21C | 109.5 |
C8—N10—C11 | 127.3 (2) | H21A—C21—H21C | 109.5 |
C8—N10—H10 | 117.7 (18) | H21B—C21—H21C | 109.5 |
C11—N10—H10 | 114.6 (18) | C5—O22—C23 | 117.54 (19) |
C16—C11—C12 | 120.1 (2) | O22—C23—H23A | 109.5 |
C16—C11—N10 | 120.7 (2) | O22—C23—H23B | 109.5 |
C12—C11—N10 | 119.1 (2) | H23A—C23—H23B | 109.5 |
C11—C12—C13 | 119.8 (3) | O22—C23—H23C | 109.5 |
C11—C12—H12 | 120.1 | H23A—C23—H23C | 109.5 |
C13—C12—H12 | 120.1 | H23B—C23—H23C | 109.5 |
C14—C13—C12 | 119.8 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H7···S9i | 0.81 (3) | 2.61 (3) | 3.383 (3) | 160 (2) |
N10—H10···O22ii | 0.81 (2) | 2.22 (3) | 2.975 (3) | 156 (2) |
O17—H17···S9iii | 0.97 (3) | 2.25 (4) | 3.211 (2) | 173 (3) |
Symmetry codes: (i) −x, −y, −z+1; (ii) −x+1, −y, −z+1; (iii) −x, −y, −z. |
Experimental details
Crystal data | |
Chemical formula | C16H18N2O4S |
Mr | 334.38 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 296 |
a, b, c (Å) | 10.5705 (5), 12.8195 (7), 12.4157 (7) |
β (°) | 99.434 (3) |
V (Å3) | 1659.68 (15) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.22 |
Crystal size (mm) | 0.15 × 0.08 × 0.03 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 12193, 3166, 1723 |
Rint | 0.050 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.121, 0.94 |
No. of reflections | 3166 |
No. of parameters | 219 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.50, −0.27 |
Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2010), WinGX (Farrugia, 1999).
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H7···S9i | 0.81 (3) | 2.61 (3) | 3.383 (3) | 160 (2) |
N10—H10···O22ii | 0.81 (2) | 2.22 (3) | 2.975 (3) | 156 (2) |
O17—H17···S9iii | 0.97 (3) | 2.25 (4) | 3.211 (2) | 173 (3) |
Symmetry codes: (i) −x, −y, −z+1; (ii) −x+1, −y, −z+1; (iii) −x, −y, −z. |
Acknowledgements
This work is the result of a study performed under the "Human Resource Development Center for Economic Region Leading Industry" Project, supported by the Ministry of Education, Science & Technology(MEST) and the National Research Foundation of Korea (NRF).
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Melanin production is primary responsible for the skin color, and melanin plays a key role in protecting human skin from the harmful UV-induced skin damages. Tyrosinase is the key enzyme (Ha et al., 2007; Kubo et al., 2000)) that converts tyrosine to melanin and its inhibitors are the target molecules to develop and research anti-pigmentation agents for the application to skin care. Numerous potential tyrosinase inhibitors have been discovered from natural and synthetic sources, such as ascorbic acid (Kojima et al., 1995), kojic acid (Cabanes et al., 1994), arbutin (Casanola-Martin et al., 2006) and tropolone (Son et al., 2000; Iida et al., 1995). Some thiourea derivatives, such as phenylthiourea (Thanigaimalai et al., 2010; Klabunde et al., 1998; Criton, 2006), alkylthiourea (Daniel, 2006), thiosemicarbazone (Yi et al., 2009) and thiosemicarbazide (Liu et al., 2009) have been also reported. During our works on developing potent whitening agents preventing the inadequacies of current whitening agents (poor skin penetration and toxicity) and minimizing the inhibitory effects of melanin creation, we have synthesized the title compound from the reaction of 3,4,5-trimethoxyphenyl isothiocyanate and 4-aminophenol under ambient condition.
The 3,4,5-trimethoxyphenyl moiety is almost planar with r.m.s. deviation of 0.050 Å from the corresponding least-squares plane defined by the ten constituent atoms. The dihedral angle between the phenyl ring and the plane of thiourea moiety is 54.53 (8) °. In the crystal, intermolecular N—H···S, N—H···O, and O—H···S hydrogen bonds link the molecules into a three-dimensional network (Fig. 2, Table 1). The H atoms of the NH groups of thiourea are positioned anti to each other.