organic compounds
1-(2,5-Dimethoxyphenyl)-3-(2-hydroxyethyl)urea
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, C11H16N2O4, the 2,5-dimethoxyphenyl moiety is almost planar, with an r.m.s. deviation of 0.026 Å. The dihedral angle between the benzene ring and the plane of the urea moiety is 13.86 (5)°. The molecular structure is stabilized by a short intramolecular N—H⋯O hydrogen bond. In the crystal, intermolecular N—H⋯O and O—H⋯O hydrogen bonds link the molecules into a three-dimensional network.
Related literature
For general background, see: Francisco et al. (2006); Jimenez et al. (2001); Korner & Pawelek (1982); Urabe et al. (1998). For the development of potent inhibitory agents of tyrosinase and melanin formation as whitening agents, see: Battaini et al. (2000); Cabanes et al. (1994); Choi et al. (2010); Germanas et al. (2007); Hong et al. (2008); Kwak et al. (2010); Lemic-Stojcevic et al. (1995); Lee et al. (2007); Liangli (2003); Thanigaimalai et al. (2010); Yi et al. (2009, 2010).
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: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 2010); software used to prepare material for publication: WinGX (Farrugia, 1999).
Supporting information
https://doi.org/10.1107/S1600536810028436/jh2184sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810028436/jh2184Isup2.hkl
The ethanolamine and 2,5-dimethoxyphenyl isocyanate 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 ethanolamine (0.1 ml, 2 mmol) with 2,5-dimethoxyphenyl isocyanate (0.5 g, 3 mmol) in acetonitrile (6 ml). The reaction was completed within 10 min at room temperature. The reaction mixture was filtered rapidly with ether. Removal of the solvent gave a white solid (90% m.p. 419 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 = 0.93–0.97 Å, and with Uiso(H) = 1.2Ueq (C) for aromatic and metylene, and 1.5Ueq(C) for methyl H atoms.
The melanin production is primarily responsible for the skin color, and melanin plays a vital role in the absorption of free radicals formed in cytoplasm and in protecting human skin from the harmful UV-radiation and from scavenging chemicals (Francisco et al., 2006). Tyrosinase is a multi-functional copper-containing enzyme widely distributed in microorganisms, plants and animals (Jimenez et al., 2001), and it is a key enzyme that catalyzes two distinct reactions of melanin synthesis; the hydroxylation of tyrosine by monophenolase action and the oxidation of L-dopa to o-dopaquinone by diphenolase action (Korner & Pawelek, 1982). The increased production and accumulation of melanin characterizes a large number of dermatological disorders, which include acquired hyper-pigmentation, causing melasma, freckles, post-inflammatory melanoderma, and solar lentigo (Urabe et al., 1998). Therefore, treatments using potent inhibitory agents on tyrosinase and melanin formation may be cosmetically useful. In recent years, various inhibitors were obtained from natural and synthetic sources with their industrial importance such as azelaic acid (Lemic-Stojcevic et al., 1995), kojic acid (Battaini et al., 2000), albutin (Cabanes et al., 1994), (R)-HTCCA (Liangli, 2003) and N-phenylthiourea (Thanigaimalai et al., 2010). They contain aromatic, methoxy, hyroxyl (Hong et al., 2008; Lee et al., 2007), aldehyde (Yi et al., 2010), amide (Kwak et al., 2010; Choi et al., 2010), thiosemicarbazone (Yi et al., 2009) and thiazole (Germanas et al., 2007) groups in their structure, and act as a specific
to make the skin whiter by inhibiting the production of melanin. However, most of them are not potent enough to put into practical use due to their weak individual activities, poor skin penetration, low stability of formulations, toxicity and/or safety concerns. Consequently, much research is needed to develop novel tyrosinase inhibitors with better activities together with lower side effects. To complement the inadequacy of current whitening agents mentioned above and maximize the inhibition of melanin creation, we have synthesized the title compound, 1-(2,5-dimethoxyphenyl)-3-(2-hydroxyethyl)urea, (I), from the reaction of ethanolamine and 2,5-dimethoxyphenyl isocyanate under ambient condition.The 2,5-dimethoxyphenyl moiety is almost planar with r.m.s. deviation of 0.026 Å from the corresponding least-squares plane defined by the ten constituent atoms. The dihedral angle between the phenyl ring and the plane of urea moiety is 13.86 (5) °. The molecular structure is stabilized by a short intramolecular N7—H7···O14 hydrogen bond (Fig. 1). In the crystal, intermolecular N—H···O and O—H···O hydrogen bonds link the molecules into a three-dimensional network (Fig. 2).
For general background, see: Francisco et al. (2006); Jimenez et al. (2001); Korner & Pawelek (1982); Urabe et al. (1998). For the development of potent inhibitory agents of tyrosinase and melanin formation as whitening agents, see: Battaini et al. (2000); Cabanes et al. (1994); Choi et al. (2010); Germanas et al. (2007); Hong et al. (2008); Kwak et al. (2010); Lemic-Stojcevic et al. (1995); Lee et al. (2007); Liangli (2003); Thanigaimalai et al. (2010); Yi et al. (2009, 2010).
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: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 2010); software used to prepare material for publication: WinGX (Farrugia, 1999).C11H16N2O4 | F(000) = 512 |
Mr = 240.26 | Dx = 1.358 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 4246 reflections |
a = 10.8571 (9) Å | θ = 2.8–28.2° |
b = 11.5559 (10) Å | µ = 0.10 mm−1 |
c = 9.9337 (8) Å | T = 173 K |
β = 109.514 (4)° | Block, colourless |
V = 1174.73 (17) Å3 | 0.21 × 0.18 × 0.09 mm |
Z = 4 |
Bruker SMART CCD area-detector diffractometer | Rint = 0.062 |
φ and ω scans | θmax = 26.5°, θmin = 2.7° |
9411 measured reflections | h = −6→13 |
2352 independent reflections | k = −14→9 |
1982 reflections with I > 2σ(I) | l = −12→7 |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.034 | w = 1/[σ2(Fo2) + (0.0526P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.090 | (Δ/σ)max < 0.001 |
S = 1.07 | Δρmax = 0.19 e Å−3 |
2352 reflections | Δρmin = −0.25 e Å−3 |
168 parameters |
C11H16N2O4 | V = 1174.73 (17) Å3 |
Mr = 240.26 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 10.8571 (9) Å | µ = 0.10 mm−1 |
b = 11.5559 (10) Å | T = 173 K |
c = 9.9337 (8) Å | 0.21 × 0.18 × 0.09 mm |
β = 109.514 (4)° |
Bruker SMART CCD area-detector diffractometer | 1982 reflections with I > 2σ(I) |
9411 measured reflections | Rint = 0.062 |
2352 independent reflections |
R[F2 > 2σ(F2)] = 0.034 | 0 restraints |
wR(F2) = 0.090 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.07 | Δρmax = 0.19 e Å−3 |
2352 reflections | Δρmin = −0.25 e Å−3 |
168 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 | 0.26322 (10) | 0.50237 (9) | 0.48181 (12) | 0.0208 (2) | |
C2 | 0.15431 (11) | 0.43224 (9) | 0.47055 (12) | 0.0220 (3) | |
C3 | 0.05312 (11) | 0.42372 (9) | 0.34222 (12) | 0.0252 (3) | |
H3 | −0.019 | 0.3778 | 0.3357 | 0.03* | |
C4 | 0.05831 (11) | 0.48333 (9) | 0.22288 (13) | 0.0264 (3) | |
H4 | −0.0101 | 0.4778 | 0.1366 | 0.032* | |
C5 | 0.16604 (11) | 0.55102 (9) | 0.23333 (12) | 0.0242 (3) | |
C6 | 0.26888 (11) | 0.56150 (9) | 0.36195 (12) | 0.0228 (3) | |
H6 | 0.3407 | 0.6076 | 0.3677 | 0.027* | |
N7 | 0.36023 (9) | 0.50709 (8) | 0.61700 (10) | 0.0234 (2) | |
H7 | 0.3458 (12) | 0.4616 (12) | 0.6799 (15) | 0.035 (4)* | |
C8 | 0.45894 (10) | 0.58708 (9) | 0.66522 (12) | 0.0205 (2) | |
O9 | 0.48440 (8) | 0.65994 (6) | 0.58761 (8) | 0.0260 (2) | |
N10 | 0.52601 (9) | 0.57919 (8) | 0.80586 (11) | 0.0250 (2) | |
H10 | 0.5012 (13) | 0.5293 (11) | 0.8553 (15) | 0.033 (3)* | |
C11 | 0.62695 (11) | 0.66229 (10) | 0.87792 (12) | 0.0268 (3) | |
H11A | 0.5892 | 0.7391 | 0.8696 | 0.032* | |
H11B | 0.6936 | 0.6631 | 0.8329 | 0.032* | |
C12 | 0.68773 (11) | 0.63093 (10) | 1.03317 (13) | 0.0271 (3) | |
H12A | 0.7315 | 0.5568 | 1.0407 | 0.032* | |
H12B | 0.7531 | 0.6884 | 1.0801 | 0.032* | |
O13 | 0.59367 (8) | 0.62435 (7) | 1.10450 (9) | 0.0260 (2) | |
H13 | 0.5628 (15) | 0.6954 (15) | 1.1048 (16) | 0.054 (5)* | |
O14 | 0.15906 (8) | 0.37701 (6) | 0.59484 (9) | 0.0274 (2) | |
C15 | 0.05328 (12) | 0.30175 (10) | 0.58780 (14) | 0.0312 (3) | |
H15A | −0.0265 | 0.3454 | 0.5619 | 0.047* | |
H15B | 0.0686 | 0.2662 | 0.6793 | 0.047* | |
H15C | 0.0465 | 0.2429 | 0.5175 | 0.047* | |
O16 | 0.16393 (8) | 0.60560 (7) | 0.10891 (9) | 0.0329 (2) | |
C17 | 0.26678 (12) | 0.68455 (11) | 0.11745 (14) | 0.0343 (3) | |
H17A | 0.267 | 0.7454 | 0.1833 | 0.051* | |
H17B | 0.2539 | 0.717 | 0.0248 | 0.051* | |
H17C | 0.3489 | 0.6445 | 0.15 | 0.051* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0197 (5) | 0.0189 (5) | 0.0216 (6) | 0.0014 (4) | 0.0039 (5) | −0.0032 (4) |
C2 | 0.0235 (6) | 0.0185 (5) | 0.0240 (6) | 0.0011 (4) | 0.0078 (5) | −0.0006 (4) |
C3 | 0.0214 (6) | 0.0238 (6) | 0.0283 (7) | −0.0040 (5) | 0.0057 (5) | −0.0044 (5) |
C4 | 0.0232 (6) | 0.0288 (6) | 0.0226 (7) | −0.0007 (5) | 0.0013 (5) | −0.0040 (5) |
C5 | 0.0259 (6) | 0.0244 (6) | 0.0207 (6) | 0.0029 (5) | 0.0058 (5) | −0.0004 (4) |
C6 | 0.0213 (6) | 0.0227 (5) | 0.0234 (6) | −0.0017 (4) | 0.0063 (5) | −0.0010 (5) |
N7 | 0.0239 (5) | 0.0238 (5) | 0.0197 (5) | −0.0049 (4) | 0.0034 (5) | 0.0027 (4) |
C8 | 0.0192 (6) | 0.0200 (5) | 0.0215 (6) | 0.0012 (4) | 0.0058 (5) | −0.0016 (4) |
O9 | 0.0280 (5) | 0.0256 (4) | 0.0225 (5) | −0.0062 (3) | 0.0061 (4) | 0.0023 (3) |
N10 | 0.0258 (5) | 0.0261 (5) | 0.0200 (6) | −0.0075 (4) | 0.0034 (5) | 0.0014 (4) |
C11 | 0.0240 (6) | 0.0309 (6) | 0.0237 (7) | −0.0082 (5) | 0.0054 (5) | −0.0030 (5) |
C12 | 0.0223 (6) | 0.0321 (6) | 0.0241 (7) | −0.0023 (5) | 0.0042 (5) | −0.0035 (5) |
O13 | 0.0307 (5) | 0.0228 (4) | 0.0247 (5) | −0.0005 (3) | 0.0095 (4) | 0.0010 (3) |
O14 | 0.0259 (4) | 0.0278 (4) | 0.0264 (5) | −0.0069 (3) | 0.0060 (4) | 0.0041 (3) |
C15 | 0.0289 (6) | 0.0268 (6) | 0.0378 (7) | −0.0076 (5) | 0.0111 (6) | 0.0028 (5) |
O16 | 0.0316 (5) | 0.0406 (5) | 0.0220 (5) | −0.0059 (4) | 0.0031 (4) | 0.0058 (4) |
C17 | 0.0330 (7) | 0.0360 (7) | 0.0326 (7) | −0.0024 (5) | 0.0092 (6) | 0.0094 (6) |
C1—C6 | 1.3918 (15) | N10—H10 | 0.856 (14) |
C1—N7 | 1.4039 (15) | C11—C12 | 1.5051 (16) |
C1—C2 | 1.4068 (15) | C11—H11A | 0.97 |
C2—O14 | 1.3754 (13) | C11—H11B | 0.97 |
C2—C3 | 1.3806 (17) | C12—O13 | 1.4262 (13) |
C3—C4 | 1.3883 (16) | C12—H12A | 0.97 |
C3—H3 | 0.93 | C12—H12B | 0.97 |
C4—C5 | 1.3819 (16) | O13—H13 | 0.887 (17) |
C4—H4 | 0.93 | O14—C15 | 1.4236 (13) |
C5—O16 | 1.3809 (13) | C15—H15A | 0.96 |
C5—C6 | 1.3931 (17) | C15—H15B | 0.96 |
C6—H6 | 0.93 | C15—H15C | 0.96 |
N7—C8 | 1.3746 (14) | O16—C17 | 1.4224 (14) |
N7—H7 | 0.870 (14) | C17—H17A | 0.96 |
C8—O9 | 1.2337 (12) | C17—H17B | 0.96 |
C8—N10 | 1.3457 (15) | C17—H17C | 0.96 |
N10—C11 | 1.4531 (14) | ||
C6—C1—N7 | 124.46 (10) | N10—C11—C12 | 110.24 (9) |
C6—C1—C2 | 119.40 (10) | N10—C11—H11A | 109.6 |
N7—C1—C2 | 116.14 (10) | C12—C11—H11A | 109.6 |
O14—C2—C3 | 125.13 (9) | N10—C11—H11B | 109.6 |
O14—C2—C1 | 114.68 (10) | C12—C11—H11B | 109.6 |
C3—C2—C1 | 120.19 (10) | H11A—C11—H11B | 108.1 |
C2—C3—C4 | 120.42 (10) | O13—C12—C11 | 112.35 (10) |
C2—C3—H3 | 119.8 | O13—C12—H12A | 109.1 |
C4—C3—H3 | 119.8 | C11—C12—H12A | 109.1 |
C5—C4—C3 | 119.44 (11) | O13—C12—H12B | 109.1 |
C5—C4—H4 | 120.3 | C11—C12—H12B | 109.1 |
C3—C4—H4 | 120.3 | H12A—C12—H12B | 107.9 |
O16—C5—C4 | 115.51 (10) | C12—O13—H13 | 106.6 (10) |
O16—C5—C6 | 123.35 (10) | C2—O14—C15 | 116.85 (9) |
C4—C5—C6 | 121.13 (10) | O14—C15—H15A | 109.5 |
C1—C6—C5 | 119.41 (10) | O14—C15—H15B | 109.5 |
C1—C6—H6 | 120.3 | H15A—C15—H15B | 109.5 |
C5—C6—H6 | 120.3 | O14—C15—H15C | 109.5 |
C8—N7—C1 | 127.44 (9) | H15A—C15—H15C | 109.5 |
C8—N7—H7 | 117.6 (9) | H15B—C15—H15C | 109.5 |
C1—N7—H7 | 114.0 (9) | C5—O16—C17 | 117.49 (9) |
O9—C8—N10 | 122.59 (10) | O16—C17—H17A | 109.5 |
O9—C8—N7 | 123.54 (10) | O16—C17—H17B | 109.5 |
N10—C8—N7 | 113.87 (9) | H17A—C17—H17B | 109.5 |
C8—N10—C11 | 121.61 (9) | O16—C17—H17C | 109.5 |
C8—N10—H10 | 118.4 (9) | H17A—C17—H17C | 109.5 |
C11—N10—H10 | 119.5 (9) | H17B—C17—H17C | 109.5 |
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H7···O14 | 0.870 (14) | 2.153 (13) | 2.5995 (12) | 111.4 (11) |
N7—H7···O13i | 0.870 (14) | 2.251 (14) | 3.0473 (13) | 152.3 (12) |
N10—H10···O13i | 0.856 (14) | 2.156 (14) | 2.9642 (12) | 157.1 (12) |
O13—H13···O9ii | 0.887 (17) | 1.858 (18) | 2.7417 (11) | 174.0 (15) |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) x, −y+3/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C11H16N2O4 |
Mr | 240.26 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 173 |
a, b, c (Å) | 10.8571 (9), 11.5559 (10), 9.9337 (8) |
β (°) | 109.514 (4) |
V (Å3) | 1174.73 (17) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.21 × 0.18 × 0.09 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9411, 2352, 1982 |
Rint | 0.062 |
(sin θ/λ)max (Å−1) | 0.628 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.034, 0.090, 1.07 |
No. of reflections | 2352 |
No. of parameters | 168 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.19, −0.25 |
Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 2010), WinGX (Farrugia, 1999).
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H7···O14 | 0.870 (14) | 2.153 (13) | 2.5995 (12) | 111.4 (11) |
N7—H7···O13i | 0.870 (14) | 2.251 (14) | 3.0473 (13) | 152.3 (12) |
N10—H10···O13i | 0.856 (14) | 2.156 (14) | 2.9642 (12) | 157.1 (12) |
O13—H13···O9ii | 0.887 (17) | 1.858 (18) | 2.7417 (11) | 174.0 (15) |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) x, −y+3/2, z+1/2. |
Acknowledgements
We wish to thank the DBIO company for partial support of this work.
References
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The melanin production is primarily responsible for the skin color, and melanin plays a vital role in the absorption of free radicals formed in cytoplasm and in protecting human skin from the harmful UV-radiation and from scavenging chemicals (Francisco et al., 2006). Tyrosinase is a multi-functional copper-containing enzyme widely distributed in microorganisms, plants and animals (Jimenez et al., 2001), and it is a key enzyme that catalyzes two distinct reactions of melanin synthesis; the hydroxylation of tyrosine by monophenolase action and the oxidation of L-dopa to o-dopaquinone by diphenolase action (Korner & Pawelek, 1982). The increased production and accumulation of melanin characterizes a large number of dermatological disorders, which include acquired hyper-pigmentation, causing melasma, freckles, post-inflammatory melanoderma, and solar lentigo (Urabe et al., 1998). Therefore, treatments using potent inhibitory agents on tyrosinase and melanin formation may be cosmetically useful. In recent years, various inhibitors were obtained from natural and synthetic sources with their industrial importance such as azelaic acid (Lemic-Stojcevic et al., 1995), kojic acid (Battaini et al., 2000), albutin (Cabanes et al., 1994), (R)-HTCCA (Liangli, 2003) and N-phenylthiourea (Thanigaimalai et al., 2010). They contain aromatic, methoxy, hyroxyl (Hong et al., 2008; Lee et al., 2007), aldehyde (Yi et al., 2010), amide (Kwak et al., 2010; Choi et al., 2010), thiosemicarbazone (Yi et al., 2009) and thiazole (Germanas et al., 2007) groups in their structure, and act as a specific functional group to make the skin whiter by inhibiting the production of melanin. However, most of them are not potent enough to put into practical use due to their weak individual activities, poor skin penetration, low stability of formulations, toxicity and/or safety concerns. Consequently, much research is needed to develop novel tyrosinase inhibitors with better activities together with lower side effects. To complement the inadequacy of current whitening agents mentioned above and maximize the inhibition of melanin creation, we have synthesized the title compound, 1-(2,5-dimethoxyphenyl)-3-(2-hydroxyethyl)urea, (I), from the reaction of ethanolamine and 2,5-dimethoxyphenyl isocyanate under ambient condition.
The 2,5-dimethoxyphenyl moiety is almost planar with r.m.s. deviation of 0.026 Å from the corresponding least-squares plane defined by the ten constituent atoms. The dihedral angle between the phenyl ring and the plane of urea moiety is 13.86 (5) °. The molecular structure is stabilized by a short intramolecular N7—H7···O14 hydrogen bond (Fig. 1). In the crystal, intermolecular N—H···O and O—H···O hydrogen bonds link the molecules into a three-dimensional network (Fig. 2).