organic compounds
Benzyl N-{(1S)-2-hydroxy-1-[N′-(2-nitrobenzylidene)hydrazinylcarbonyl]ethyl}carbamate
aFundação Oswaldo Cruz, Instituto de Tecnologia em Fármacos – Farmanguinhos, R. Sizenando Nabuco, 100, Manguinhos, 21041-250 Rio de Janeiro, RJ, Brazil, bDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia, cCHEMSOL, 1 Harcourt Road, Aberdeen AB15 5NY, Scotland, and dCentro de Desenvolvimento Tecnológico em Saúde (CDTS), Fundação Oswaldo Cruz (FIOCRUZ), Casa Amarela, Campus de Manguinhos, Av. Brasil 4365, 21040-900 Rio de Janeiro, RJ, Brazil
*Correspondence e-mail: edward.tiekink@gmail.com
The carbamate and hydrazone groups in the title compound, C18H18N4O6, are approximately orthogonal [dihedral angle = 83.3 (4)°], and the carbonyl groups are effectively anti [O=C⋯C=O torsion angle = −116.2 (7)°]. The conformation about the imine bond [1.295 (11) Å] is E. The crystal packing is dominated by O—H⋯O and N—H⋯O hydrogen bonding, which leads to two-dimensional arrays in the ab plane.
Related literature
For background to the anti-tumour potential of L-serine derivatives, see: Jiao et al. (2009); Yakura et al. (2007); Takahashi et al. (1988); Sin et al. (1998). For background of the anti-tumour potential of N-acylhydrazone L-serine derivatives, see: Rollas & Küçükgüzel (2007); Terzioğlu & Gürsoy (2003).
Experimental
Crystal data
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Refinement
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Data collection: COLLECT (Hooft, 1998); cell DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).
Supporting information
https://doi.org/10.1107/S1600536810027273/zs2049sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810027273/zs2049Isup2.hkl
An ethanolic solution of 2-nitrobenzaldehyde (1.05 mmol) and PhCH2O(CO)NHCH(CH2OH)CONHNH2, prepared from L-serine and hydrazine hydrate, (1.0 mmol) was refluxed for 4 h. After rotary evaporation, the residue was washed with cold ethanol (3 x 10 ml), and recrystallized from methanol. The crystals used in the
were grown from methanol solution, m.p. 428–429 K.1H NMR (500 MHz, DMSO-d6) δ (p.p.m.): 11.88 and 11.71 (1H, s, NHN, (E/Z)-diastereomer), 8.66 and 8.39 (1H, s, N═CH, (E/Z)-diastereomer), 8.07 (2H, m, H3 and H6), 7.80 (1H, m, H5), 7.67 (1H, m, H4), 7.44 (d, J = 7.8) and 7.34 (m), (1H, NHCH, (E/Z)-diastereomer), 7.38–7.30 (5H, m, Ph), 5.05 and 5.04 (2H, s, CH2Ph, (E/Z)-diastereomer), 5.03 (m) and 4.89 (t, J = 5.9), (1H, OH, (E/Z)-diastereomer), 5.03 and 4.15 (1H, m, CH, (E/Z)-diastereomer), 3.80–3.60 (2H, m, CH2OH). 13C NMR (125 MHz, DMSO-d6) δ (p.p.m.): 171.7, 167.4, 156.0, 148.2, 148.1, 142.4, 138.8, 137.0, 136.9, 133.8, 133.6, 130.6, 130.5, 128.7, 128.4, 128.0, 127.8, 127.7, 124.7, 124.6, 65.6, 65.4, 61.4, 61.1, 56.5, 54.4. IR (cm-1; KBr): 3392 (O—H), 1694 (COCH), 1672 (COO), 1555 and 1342 (NO2). EM/ESI: [M—H]: 385.3.
The C-bound H atoms were geometrically placed (C–H = 0.95–1.00 Å) and refined as riding with Uiso(H) = 1.2Ueq(C). The O– and N-bound H atoms were located from a difference map and refined with the distance restraints O–H = 0.84±0.01 and N–H = 0.88±0.01 Å, and with Uiso(H) = 1.2Ueq(N) or 1.5Ueq(O). In the absence of significant
effects, 1489 Friedel pairs were averaged in the final However, the was assigned on the basis of the chiralty of the L-serine starting material.Several L-serine derivatives have been found to have potential in anti-cancer therapy, for example, conagenin, a naturally occurring serine derivative, was shown to improve the anti-tumour efficacy of adriamycin and mitomycin C against murine leukemias (Jiao et al., 2009; Yakura et al., 2007). Other L-serine derivatives reported as potential new anti-tumour agents include the antibiotic thrazarine, which sensitizes tumour cells to macrophage-mediated cytolysis (Takahashi et al., 1988), and eponemycin, an immunomodulator, which plays a crucial role in tumour progression and metastases by supplying essential nutrients to B16 melanoma cells (Sin et al., 1998).
Following on from such reports, we have synthesized some N-acylhydrazone L-serine derivatives from L-serine to screen for anti-tumour activity. The choice of N-acylhydrazonyl derivatives was suggested by publications indicating that compounds with such groups can aid anti-tumour activities (Rollas & Küçükgüzel, 2007; Terzioğlu & Gürsoy, 2003). We now report the structure of the title compound (I). While the solid, isolated by recrystallization from methanol, was purely in the E-form, NMR spectra in DMSO-d6 solution indicated that both E and Z forms are produced.
Significant twists are evident in the molecular structure of (I) (Fig. 1). The twisting is most pronounced about the central methine link with the dihedral angle formed between the least-squares planes through the carbamate group (N1,C1,O1,O2; r.m.s. = 0.0028 Å) and the hydrazone group (N2,N2,C4,O4; r.m.s. = 0.0202 Å) being 83.3 (4)°. The dihedral angle O2–C2···C4–O4 is -116.2 (7)° indicating an anti disposition for the carbonyl-O2 and O4 atoms. While the benzyl-benzene ring is approximately co-planar with the carbamate group [the O1–C1–C12–C13 torsion angle is -171.3 (8)°], the benzene ring adjacent to the hydrazone residue is not [N3–C5–C6–C7 = -137.9 (9) °]; the dihedral angle formed between the terminal benzene rings is 67.8 (4) °. The conformation about the imine C5═N3 bond [1.295 (11) Å] is E.
The crystal packing is dominated by O–H···O and N–H···O hydrogen bonding (Table 1). The hydroxyl group hydrogen bonds with the carbonyl-O2 to form a chain along the b axis. Each N–H hydrogen-bonds to an O atom, N1–H to the hydroxy-O3 atom to form a chain along the a axis, and N3–H to a carbonyl-O4 atom to form an amide-type tape along the a axis. The net result of the hydrogen bonding is the formation of two-dimensional arrays in the ab plane (Fig. 2), that stack along the c axis (Fig. 3).
For background to the anti-tumour potential of L-serine derivatives, see: Jiao et al. (2009); Yakura et al. (2007); Takahashi et al. (1988); Sin et al. (1998). For background of the anti-tumour potential of N-acylhydrazone L-serine derivatives, see: Rollas & Küçükgüzel (2007); Terzioğlu & Gürsoy (2003).
Data collection: COLLECT (Hooft, 1998); cell
DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); data reduction: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).C18H18N4O6 | Z = 1 |
Mr = 386.36 | F(000) = 202 |
Triclinic, P1 | Dx = 1.462 Mg m−3 |
Hall symbol: P 1 | Melting point = 428–429 K |
a = 4.6675 (7) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 5.7001 (7) Å | Cell parameters from 18416 reflections |
c = 16.645 (3) Å | θ = 2.9–27.5° |
α = 90.457 (9)° | µ = 0.11 mm−1 |
β = 92.087 (7)° | T = 120 K |
γ = 97.319 (9)° | Plate, colourless |
V = 438.90 (11) Å3 | 0.20 × 0.07 × 0.01 mm |
Nonius KappaCCD area-detector diffractometer | 1791 independent reflections |
Radiation source: Enraf Nonius FR591 rotating anode | 1243 reflections with I > 2σ(I) |
10 cm confocal mirrors monochromator | Rint = 0.093 |
Detector resolution: 9.091 pixels mm-1 | θmax = 26.5°, θmin = 3.6° |
φ and ω scans | h = −5→5 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2007) | k = −6→7 |
Tmin = 0.624, Tmax = 1.000 | l = −20→20 |
7083 measured reflections |
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)] = 0.089 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.190 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.14 | w = 1/[σ2(Fo2) + (0.037P)2 + 1.2849P] where P = (Fo2 + 2Fc2)/3 |
1791 reflections | (Δ/σ)max < 0.001 |
262 parameters | Δρmax = 0.39 e Å−3 |
6 restraints | Δρmin = −0.32 e Å−3 |
C18H18N4O6 | γ = 97.319 (9)° |
Mr = 386.36 | V = 438.90 (11) Å3 |
Triclinic, P1 | Z = 1 |
a = 4.6675 (7) Å | Mo Kα radiation |
b = 5.7001 (7) Å | µ = 0.11 mm−1 |
c = 16.645 (3) Å | T = 120 K |
α = 90.457 (9)° | 0.20 × 0.07 × 0.01 mm |
β = 92.087 (7)° |
Nonius KappaCCD area-detector diffractometer | 1791 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2007) | 1243 reflections with I > 2σ(I) |
Tmin = 0.624, Tmax = 1.000 | Rint = 0.093 |
7083 measured reflections |
R[F2 > 2σ(F2)] = 0.089 | 6 restraints |
wR(F2) = 0.190 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.14 | Δρmax = 0.39 e Å−3 |
1791 reflections | Δρmin = −0.32 e Å−3 |
262 parameters |
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 | 0.2947 (12) | 0.8892 (10) | 0.3007 (4) | 0.0270 (14) | |
O2 | −0.0905 (13) | 0.6386 (10) | 0.2534 (4) | 0.0294 (15) | |
O3 | −0.4518 (12) | 1.3215 (11) | 0.1633 (4) | 0.0297 (15) | |
H3O | −0.350 (19) | 1.374 (18) | 0.204 (4) | 0.045* | |
O4 | 0.1745 (14) | 0.8327 (12) | 0.0625 (4) | 0.0395 (17) | |
O5 | −0.6765 (15) | 0.6119 (12) | −0.2286 (4) | 0.0427 (19) | |
O6 | −0.6271 (16) | 0.4575 (13) | −0.3452 (4) | 0.0450 (19) | |
N1 | 0.0112 (16) | 1.0119 (13) | 0.2030 (5) | 0.0267 (17) | |
H1N | 0.156 (13) | 1.122 (12) | 0.195 (6) | 0.032* | |
N2 | −0.2884 (15) | 0.7320 (14) | 0.0165 (5) | 0.0285 (18) | |
H2N | −0.469 (7) | 0.718 (17) | 0.031 (5) | 0.034* | |
N3 | −0.1965 (16) | 0.5952 (12) | −0.0441 (5) | 0.0272 (18) | |
N4 | −0.5754 (16) | 0.4722 (12) | −0.2727 (5) | 0.0291 (18) | |
C1 | 0.0588 (17) | 0.8301 (16) | 0.2530 (5) | 0.024 (2) | |
C2 | −0.2011 (19) | 0.9716 (15) | 0.1386 (5) | 0.025 (2) | |
H2 | −0.3785 | 0.8760 | 0.1585 | 0.030* | |
C3 | −0.278 (2) | 1.2117 (16) | 0.1085 (5) | 0.029 (2) | |
H3A | −0.0978 | 1.3188 | 0.1004 | 0.035* | |
H3B | −0.3842 | 1.1877 | 0.0559 | 0.035* | |
C4 | −0.0811 (19) | 0.8361 (14) | 0.0693 (5) | 0.0221 (19) | |
C5 | −0.398 (2) | 0.4987 (15) | −0.0938 (5) | 0.026 (2) | |
H5 | −0.5928 | 0.5308 | −0.0921 | 0.031* | |
C6 | −0.3011 (19) | 0.3339 (14) | −0.1536 (6) | 0.026 (2) | |
C7 | −0.3789 (19) | 0.3147 (14) | −0.2349 (6) | 0.026 (2) | |
C8 | −0.2776 (19) | 0.1553 (16) | −0.2870 (6) | 0.029 (2) | |
H8 | −0.3347 | 0.1492 | −0.3424 | 0.035* | |
C9 | −0.092 (2) | 0.0061 (16) | −0.2560 (6) | 0.032 (2) | |
H9 | −0.0215 | −0.1062 | −0.2902 | 0.039* | |
C10 | −0.006 (2) | 0.0190 (16) | −0.1754 (6) | 0.031 (2) | |
H10 | 0.1263 | −0.0809 | −0.1548 | 0.038* | |
C11 | −0.1140 (18) | 0.1766 (14) | −0.1252 (5) | 0.026 (2) | |
H11 | −0.0600 | 0.1790 | −0.0696 | 0.031* | |
C12 | 0.347 (2) | 0.7141 (16) | 0.3589 (6) | 0.030 (2) | |
H12A | 0.4009 | 0.5724 | 0.3313 | 0.036* | |
H12B | 0.1691 | 0.6662 | 0.3884 | 0.036* | |
C13 | 0.5886 (19) | 0.8140 (16) | 0.4173 (6) | 0.026 (2) | |
C14 | 0.737 (2) | 1.0378 (16) | 0.4112 (6) | 0.030 (2) | |
H14 | 0.6857 | 1.1380 | 0.3691 | 0.035* | |
C15 | 0.958 (2) | 1.1178 (18) | 0.4651 (6) | 0.038 (2) | |
H15 | 1.0609 | 1.2714 | 0.4596 | 0.045* | |
C16 | 1.031 (2) | 0.9758 (18) | 0.5270 (6) | 0.038 (3) | |
H16 | 1.1847 | 1.0311 | 0.5642 | 0.045* | |
C17 | 0.881 (2) | 0.7527 (18) | 0.5351 (6) | 0.037 (3) | |
H17 | 0.9294 | 0.6546 | 0.5781 | 0.045* | |
C18 | 0.659 (2) | 0.6729 (16) | 0.4798 (6) | 0.031 (2) | |
H18 | 0.5543 | 0.5199 | 0.4853 | 0.037* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.024 (3) | 0.030 (3) | 0.027 (4) | 0.003 (3) | 0.002 (3) | 0.012 (3) |
O2 | 0.021 (3) | 0.029 (3) | 0.036 (4) | −0.002 (3) | −0.002 (3) | 0.000 (3) |
O3 | 0.023 (4) | 0.035 (4) | 0.032 (4) | 0.003 (3) | 0.003 (3) | −0.006 (3) |
O4 | 0.022 (4) | 0.049 (4) | 0.047 (4) | 0.003 (3) | −0.001 (3) | −0.015 (3) |
O5 | 0.048 (5) | 0.043 (4) | 0.041 (4) | 0.024 (4) | −0.002 (4) | −0.006 (3) |
O6 | 0.053 (5) | 0.057 (5) | 0.027 (4) | 0.018 (4) | −0.008 (3) | −0.001 (3) |
N1 | 0.022 (4) | 0.032 (5) | 0.025 (4) | 0.001 (3) | −0.002 (3) | −0.006 (3) |
N2 | 0.016 (4) | 0.038 (4) | 0.032 (4) | 0.003 (3) | 0.003 (3) | −0.013 (4) |
N3 | 0.026 (4) | 0.024 (4) | 0.033 (4) | 0.003 (3) | 0.003 (4) | 0.000 (3) |
N4 | 0.030 (5) | 0.022 (4) | 0.035 (5) | 0.004 (3) | −0.004 (4) | 0.005 (3) |
C1 | 0.010 (4) | 0.037 (5) | 0.023 (5) | 0.000 (4) | −0.005 (4) | −0.008 (4) |
C2 | 0.018 (5) | 0.028 (5) | 0.028 (5) | −0.003 (4) | 0.003 (4) | −0.001 (4) |
C3 | 0.039 (6) | 0.026 (5) | 0.022 (5) | 0.003 (4) | −0.005 (4) | −0.004 (4) |
C4 | 0.026 (5) | 0.020 (4) | 0.021 (5) | 0.002 (3) | 0.013 (4) | 0.005 (3) |
C5 | 0.028 (5) | 0.028 (5) | 0.022 (5) | 0.005 (4) | 0.004 (4) | −0.006 (4) |
C6 | 0.026 (5) | 0.016 (4) | 0.037 (6) | 0.000 (4) | −0.004 (4) | −0.007 (4) |
C7 | 0.020 (5) | 0.016 (4) | 0.041 (6) | −0.004 (3) | 0.005 (4) | −0.001 (4) |
C8 | 0.032 (5) | 0.034 (5) | 0.019 (5) | 0.000 (4) | 0.000 (4) | −0.011 (4) |
C9 | 0.037 (6) | 0.027 (5) | 0.036 (6) | 0.012 (4) | 0.006 (5) | −0.013 (4) |
C10 | 0.032 (5) | 0.028 (5) | 0.034 (6) | 0.000 (4) | 0.007 (5) | −0.010 (4) |
C11 | 0.028 (5) | 0.023 (5) | 0.023 (5) | −0.005 (4) | −0.001 (4) | 0.003 (4) |
C12 | 0.031 (5) | 0.025 (5) | 0.033 (6) | 0.005 (4) | −0.005 (4) | 0.002 (4) |
C13 | 0.023 (5) | 0.030 (5) | 0.025 (5) | 0.005 (4) | 0.011 (4) | 0.000 (4) |
C14 | 0.030 (5) | 0.030 (5) | 0.028 (5) | 0.003 (4) | −0.005 (4) | −0.002 (4) |
C15 | 0.039 (6) | 0.036 (6) | 0.036 (6) | −0.001 (5) | −0.010 (5) | 0.000 (5) |
C16 | 0.026 (5) | 0.046 (6) | 0.040 (6) | 0.004 (5) | −0.007 (5) | −0.021 (5) |
C17 | 0.036 (6) | 0.043 (6) | 0.034 (6) | 0.010 (5) | −0.009 (5) | −0.004 (5) |
C18 | 0.034 (6) | 0.026 (5) | 0.031 (6) | 0.000 (4) | −0.001 (4) | 0.000 (4) |
O1—C1 | 1.340 (10) | C6—C11 | 1.402 (12) |
O1—C12 | 1.433 (10) | C7—C8 | 1.388 (12) |
O2—C1 | 1.218 (11) | C8—C9 | 1.381 (13) |
O3—C3 | 1.433 (11) | C8—H8 | 0.9500 |
O3—H3O | 0.84 (8) | C9—C10 | 1.384 (13) |
O4—C4 | 1.205 (10) | C9—H9 | 0.9500 |
O5—N4 | 1.228 (10) | C10—C11 | 1.375 (12) |
O6—N4 | 1.223 (10) | C10—H10 | 0.9500 |
N1—C1 | 1.369 (12) | C11—H11 | 0.9500 |
N1—C2 | 1.430 (11) | C12—C13 | 1.513 (13) |
N1—H1N | 0.88 (7) | C12—H12A | 0.9900 |
N2—C4 | 1.358 (11) | C12—H12B | 0.9900 |
N2—N3 | 1.383 (10) | C13—C14 | 1.379 (12) |
N2—H2N | 0.88 (4) | C13—C18 | 1.376 (13) |
N3—C5 | 1.295 (11) | C14—C15 | 1.372 (13) |
N4—C7 | 1.490 (11) | C14—H14 | 0.9500 |
C2—C4 | 1.544 (12) | C15—C16 | 1.376 (15) |
C2—C3 | 1.541 (12) | C15—H15 | 0.9500 |
C2—H2 | 1.0000 | C16—C17 | 1.381 (14) |
C3—H3A | 0.9900 | C16—H16 | 0.9500 |
C3—H3B | 0.9900 | C17—C18 | 1.391 (13) |
C5—C6 | 1.485 (12) | C17—H17 | 0.9500 |
C5—H5 | 0.9500 | C18—H18 | 0.9500 |
C6—C7 | 1.387 (13) | ||
C1—O1—C12 | 114.3 (7) | C8—C7—N4 | 115.2 (8) |
C3—O3—H3O | 110 (7) | C9—C8—C7 | 118.1 (8) |
C1—N1—C2 | 119.6 (7) | C9—C8—H8 | 120.9 |
C1—N1—H1N | 118 (6) | C7—C8—H8 | 120.9 |
C2—N1—H1N | 116 (6) | C10—C9—C8 | 120.5 (8) |
C4—N2—N3 | 116.5 (7) | C10—C9—H9 | 119.8 |
C4—N2—H2N | 118 (6) | C8—C9—H9 | 119.8 |
N3—N2—H2N | 123 (6) | C9—C10—C11 | 119.9 (9) |
C5—N3—N2 | 115.3 (7) | C9—C10—H10 | 120.1 |
O6—N4—O5 | 123.4 (8) | C11—C10—H10 | 120.1 |
O6—N4—C7 | 119.1 (7) | C10—C11—C6 | 122.0 (8) |
O5—N4—C7 | 117.5 (7) | C10—C11—H11 | 119.0 |
O2—C1—O1 | 124.3 (8) | C6—C11—H11 | 119.0 |
O2—C1—N1 | 124.7 (8) | O1—C12—C13 | 109.6 (7) |
O1—C1—N1 | 111.0 (7) | O1—C12—H12A | 109.7 |
N1—C2—C4 | 109.8 (7) | C13—C12—H12A | 109.7 |
N1—C2—C3 | 109.1 (7) | O1—C12—H12B | 109.7 |
C4—C2—C3 | 109.9 (7) | C13—C12—H12B | 109.7 |
N1—C2—H2 | 109.3 | H12A—C12—H12B | 108.2 |
C4—C2—H2 | 109.3 | C14—C13—C18 | 119.1 (8) |
C3—C2—H2 | 109.3 | C14—C13—C12 | 123.3 (8) |
O3—C3—C2 | 112.7 (7) | C18—C13—C12 | 117.5 (8) |
O3—C3—H3A | 109.1 | C13—C14—C15 | 120.9 (9) |
C2—C3—H3A | 109.1 | C13—C14—H14 | 119.6 |
O3—C3—H3B | 109.1 | C15—C14—H14 | 119.6 |
C2—C3—H3B | 109.1 | C16—C15—C14 | 120.1 (10) |
H3A—C3—H3B | 107.8 | C16—C15—H15 | 120.0 |
O4—C4—N2 | 124.3 (8) | C14—C15—H15 | 120.0 |
O4—C4—C2 | 121.9 (8) | C15—C16—C17 | 120.0 (9) |
N2—C4—C2 | 113.7 (7) | C15—C16—H16 | 120.0 |
N3—C5—C6 | 114.6 (8) | C17—C16—H16 | 120.0 |
N3—C5—H5 | 122.7 | C16—C17—C18 | 119.4 (10) |
C6—C5—H5 | 122.7 | C16—C17—H17 | 120.3 |
C7—C6—C11 | 115.8 (8) | C18—C17—H17 | 120.3 |
C7—C6—C5 | 127.2 (8) | C13—C18—C17 | 120.5 (9) |
C11—C6—C5 | 117.0 (8) | C13—C18—H18 | 119.7 |
C6—C7—C8 | 123.6 (8) | C17—C18—H18 | 119.7 |
C6—C7—N4 | 121.2 (7) | ||
C4—N2—N3—C5 | −179.8 (9) | O6—N4—C7—C6 | 176.4 (9) |
C12—O1—C1—O2 | −5.2 (12) | O5—N4—C7—C6 | −3.3 (12) |
C12—O1—C1—N1 | 175.7 (7) | O6—N4—C7—C8 | −2.2 (11) |
C2—N1—C1—O2 | −9.2 (13) | O5—N4—C7—C8 | 178.1 (8) |
C2—N1—C1—O1 | 169.9 (7) | C6—C7—C8—C9 | 0.7 (13) |
C1—N1—C2—C4 | −76.5 (9) | N4—C7—C8—C9 | 179.2 (8) |
C1—N1—C2—C3 | 163.0 (8) | C7—C8—C9—C10 | −1.0 (14) |
N1—C2—C3—O3 | −73.3 (9) | C8—C9—C10—C11 | 1.9 (14) |
C4—C2—C3—O3 | 166.2 (7) | C9—C10—C11—C6 | −2.6 (14) |
N3—N2—C4—O4 | 6.5 (13) | C7—C6—C11—C10 | 2.2 (12) |
N3—N2—C4—C2 | −176.0 (7) | C5—C6—C11—C10 | −178.9 (8) |
N1—C2—C4—O4 | −20.2 (11) | C1—O1—C12—C13 | −171.3 (8) |
C3—C2—C4—O4 | 99.8 (10) | O1—C12—C13—C14 | −2.3 (12) |
N1—C2—C4—N2 | 162.3 (8) | O1—C12—C13—C18 | 177.0 (8) |
C3—C2—C4—N2 | −77.7 (9) | C18—C13—C14—C15 | 2.0 (14) |
N2—N3—C5—C6 | −174.3 (7) | C12—C13—C14—C15 | −178.8 (9) |
N3—C5—C6—C7 | −137.9 (9) | C13—C14—C15—C16 | −1.1 (15) |
N3—C5—C6—C11 | 43.3 (12) | C14—C15—C16—C17 | −0.2 (15) |
C11—C6—C7—C8 | −1.3 (12) | C15—C16—C17—C18 | 0.6 (15) |
C5—C6—C7—C8 | 179.9 (9) | C14—C13—C18—C17 | −1.6 (14) |
C11—C6—C7—N4 | −179.7 (8) | C12—C13—C18—C17 | 179.2 (9) |
C5—C6—C7—N4 | 1.5 (13) | C16—C17—C18—C13 | 0.3 (15) |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3o···O2i | 0.84 (8) | 1.97 (9) | 2.712 (9) | 147 (8) |
N1—H1n···O3ii | 0.88 (7) | 2.12 (7) | 2.974 (10) | 167 (8) |
N2—H2n···O4iii | 0.88 (4) | 1.95 (5) | 2.775 (10) | 155 (9) |
Symmetry codes: (i) x, y+1, z; (ii) x+1, y, z; (iii) x−1, y, z. |
Experimental details
Crystal data | |
Chemical formula | C18H18N4O6 |
Mr | 386.36 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 120 |
a, b, c (Å) | 4.6675 (7), 5.7001 (7), 16.645 (3) |
α, β, γ (°) | 90.457 (9), 92.087 (7), 97.319 (9) |
V (Å3) | 438.90 (11) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 0.11 |
Crystal size (mm) | 0.20 × 0.07 × 0.01 |
Data collection | |
Diffractometer | Nonius KappaCCD area-detector |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2007) |
Tmin, Tmax | 0.624, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7083, 1791, 1243 |
Rint | 0.093 |
(sin θ/λ)max (Å−1) | 0.628 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.089, 0.190, 1.14 |
No. of reflections | 1791 |
No. of parameters | 262 |
No. of restraints | 6 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.39, −0.32 |
Computer programs: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3o···O2i | 0.84 (8) | 1.97 (9) | 2.712 (9) | 147 (8) |
N1—H1n···O3ii | 0.88 (7) | 2.12 (7) | 2.974 (10) | 167 (8) |
N2—H2n···O4iii | 0.88 (4) | 1.95 (5) | 2.775 (10) | 155 (9) |
Symmetry codes: (i) x, y+1, z; (ii) x+1, y, z; (iii) x−1, y, z. |
Footnotes
‡Additional correspondence author, e-mail: j.wardell@abdn.ac.uk.
Acknowledgements
The use of the EPSRC X-ray crystallographic service at the University of Southampton, England, and the valuable assistance of the staff there is gratefully acknowledged. JLW acknowledges support from CAPES (Brazil).
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.
Several L-serine derivatives have been found to have potential in anti-cancer therapy, for example, conagenin, a naturally occurring serine derivative, was shown to improve the anti-tumour efficacy of adriamycin and mitomycin C against murine leukemias (Jiao et al., 2009; Yakura et al., 2007). Other L-serine derivatives reported as potential new anti-tumour agents include the antibiotic thrazarine, which sensitizes tumour cells to macrophage-mediated cytolysis (Takahashi et al., 1988), and eponemycin, an immunomodulator, which plays a crucial role in tumour progression and metastases by supplying essential nutrients to B16 melanoma cells (Sin et al., 1998).
Following on from such reports, we have synthesized some N-acylhydrazone L-serine derivatives from L-serine to screen for anti-tumour activity. The choice of N-acylhydrazonyl derivatives was suggested by publications indicating that compounds with such groups can aid anti-tumour activities (Rollas & Küçükgüzel, 2007; Terzioğlu & Gürsoy, 2003). We now report the structure of the title compound (I). While the solid, isolated by recrystallization from methanol, was purely in the E-form, NMR spectra in DMSO-d6 solution indicated that both E and Z forms are produced.
Significant twists are evident in the molecular structure of (I) (Fig. 1). The twisting is most pronounced about the central methine link with the dihedral angle formed between the least-squares planes through the carbamate group (N1,C1,O1,O2; r.m.s. = 0.0028 Å) and the hydrazone group (N2,N2,C4,O4; r.m.s. = 0.0202 Å) being 83.3 (4)°. The dihedral angle O2–C2···C4–O4 is -116.2 (7)° indicating an anti disposition for the carbonyl-O2 and O4 atoms. While the benzyl-benzene ring is approximately co-planar with the carbamate group [the O1–C1–C12–C13 torsion angle is -171.3 (8)°], the benzene ring adjacent to the hydrazone residue is not [N3–C5–C6–C7 = -137.9 (9) °]; the dihedral angle formed between the terminal benzene rings is 67.8 (4) °. The conformation about the imine C5═N3 bond [1.295 (11) Å] is E.
The crystal packing is dominated by O–H···O and N–H···O hydrogen bonding (Table 1). The hydroxyl group hydrogen bonds with the carbonyl-O2 to form a chain along the b axis. Each N–H hydrogen-bonds to an O atom, N1–H to the hydroxy-O3 atom to form a chain along the a axis, and N3–H to a carbonyl-O4 atom to form an amide-type tape along the a axis. The net result of the hydrogen bonding is the formation of two-dimensional arrays in the ab plane (Fig. 2), that stack along the c axis (Fig. 3).