supplementary materials


hg5150 scheme

Acta Cryst. (2012). E68, o177    [ doi:10.1107/S1600536811052767 ]

(S)-Methyl 2-benzamido-3-(3,4-dimethoxyphenyl)propanoate

T. Naicker, T. Govender, H. G. Kruger and G. E. M. Maguire

Abstract top

The dimethoxypbenzene ring in the title compound, C19H21NO5, is gauche to the amide group and anti to the ester group. The chirality was confirmed to be S from two-dimensional NMR spectroscopy. In the crystal, N-H...O and C-H...O hydrogen bonds and several short-contact interactions (2.07-3.45 Å) create chains parallel to [110]. The phenyl ring is disordered over two orientations in a 0.54 (2):0.46 (2) ratio.

Comment top

The title compound is a well known precusor to several biologically active compounds (Zalán et al., 2006). In our laboratory it is being used as a precusor to novel chiral organocatalyts (Naicker et al. 2011).

There is only one analogous X-ray crystal structure that has a tertiary butyl group at the C12 position and a O—CH2-fluorenyl group is attached to the carbonyl carbon at C13 (Clegg & Elsegood, 2003). The title compound exists in a perfectly staggered conformation about the C9—C10 bond (Fig. 1). Similar to the analogous X-ray structure, the dimethoxyphenyl ring is gauche to the amide group and anti to the ester group.

The initial starting material for the synthesis of the title compound was optically pure L-DOPA, the chirality at the C8 atom remained unchanged during the synthesis and was confirmed to be S configuration from two-dimensional NMR spectroscopy.

The molecules in the crystal are connected by N1—H1···O5 (2.07 (9) Å) hydrogen bonds (Fig. 2), supported by a weak C2—H2···O5 (2.54 (11) Å) hydrogen bond from the dimethoxyphenyl ring which form chains parallel to the 110 plane (Table 2). In the analogous structure the same hydrogen bonds, have lengths of 2.36 Å and 2.42 Å respectively. In addition, there are several intermolecular short contact interactions (2.07–3.45 Å) within the crystal packing.

The phenyl ring is disordered with two orientations at 50% site occupancy.

Related literature top

The title compound is a precusor to novel chiral organocatalyts. For the synthesis, see: Naicker et al. (2011) and for related structures, see: Clegg & Elsegood (2003); Zalán et al. (2006)

Experimental top

Benzoic acid (0.5 g, 4.2 mmol) was dissolved was dissolved in DMF (15 ml) and THF (5 ml) followed by addition of HBTU (4.6 mmol), DIPEA (8.4 mmol) and (S)-methyl 2-amino-3-(3,4-dimethoxyphenyl)propanoate (1.0 g, 4.2 mmol). The reaction mixture was then stirred at room temperature until no more starting material could be detected by TLC analysis. The reaction mixture was poured into 30 volumes of chilled water; the mixture was then extracted thrice with ethyl acetate (20 ml). The combined extracts were dried over anhydrous sodium sulfate and then concentrated to dryness affording the crude product. This crude product was purified by column chromatography (50:50 EtOAc/Hexane, Rf = 0.6) to afford the product 1.30 g (92%) as a white solid. Melting point: 377–379 K.

Recrystallization from ethyl acetate at room temperature afforded crystals suitable for X-ray analysis.

Refinement top

All hydrogen atoms were positioned geometrically with C—H distances ranging from 0.95 Å to 1.00 Å and N—H distances 0.88Å and refined as riding on their parent atoms, with Uiso (H) = 1.2 - 1.5 Ueq (C or N). The final refinements were done with the Friedel pairs being merged. The phenyl ring is disordered with two orientations: the ring of C14, C15A, C16A, C17A, C18A and C19A and the other ring of C14, C15B, C16B, C17B, C18B and C19B, with C17A and C17B are at the common positions and the site occupancy factors were refined to 0.46 (2) and 0.54 (2) respectively. The bond distances of the disordered phenyl ring were restrained to 0.39 (1) Å. The hydrogen atom H1 (of N1) could not be located in the difference electron density maps and therefore was placed on a trigonal-planar position. This hydrogen position was justified by the presence of almost linear hydrogen bond N1—H1 to O5 of the neighbouring molecule.

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006; data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 40% probability level.
[Figure 2] Fig. 2. A partial projection of the title compound, viewed along the [110] plane.
(S)-Methyl 2-benzamido-3-(3,4-dimethoxyphenyl)propanoate top
Crystal data top
C19H21NO5F(000) = 728
Mr = 343.37Dx = 1.327 Mg m3
Monoclinic, C2Melting point: 378 K
Hall symbol: C 2yMo Kα radiation, λ = 0.71073 Å
a = 20.331 (9) ÅCell parameters from 3868 reflections
b = 5.070 (3) Åθ = 2.1–25.2°
c = 17.580 (9) ŵ = 0.10 mm1
β = 108.489 (8)°T = 173 K
V = 1718.5 (15) Å3Needle, colourless
Z = 40.75 × 0.05 × 0.03 mm
Data collection top
Bruker Kappa DUO APEXII
diffractometer
930 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.077
graphiteθmax = 25.2°, θmin = 2.1°
0.5° φ scans and ω scansh = 2423
3865 measured reflectionsk = 55
1645 independent reflectionsl = 2021
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.077Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.219H-atom parameters constrained
S = 0.99 w = 1/[σ2(Fo2) + (0.1349P)2]
where P = (Fo2 + 2Fc2)/3
1645 reflections(Δ/σ)max = 0.001
263 parametersΔρmax = 0.33 e Å3
13 restraintsΔρmin = 0.35 e Å3
Crystal data top
C19H21NO5V = 1718.5 (15) Å3
Mr = 343.37Z = 4
Monoclinic, C2Mo Kα radiation
a = 20.331 (9) ŵ = 0.10 mm1
b = 5.070 (3) ÅT = 173 K
c = 17.580 (9) Å0.75 × 0.05 × 0.03 mm
β = 108.489 (8)°
Data collection top
Bruker Kappa DUO APEXII
diffractometer
Rint = 0.077
3865 measured reflectionsθmax = 25.2°
1645 independent reflectionsStandard reflections: 0
930 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.077H-atom parameters constrained
wR(F2) = 0.219Δρmax = 0.33 e Å3
S = 0.99Δρmin = 0.35 e Å3
1645 reflectionsAbsolute structure: ?
263 parametersFlack parameter: ?
13 restraintsRogers parameter: ?
Special details top

Experimental. Half sphere of data collected using the Bruker SAINT software package. Crystal to detector distance = 30 mm; combination of φ and ω scans of 0.5°, 120 s per °, 2 iterations.

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.

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 > σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
O10.4617 (3)0.3079 (14)0.6767 (3)0.0559 (17)
O20.3895 (3)0.0530 (15)0.7181 (3)0.0518 (16)
O30.8139 (3)0.0862 (15)0.9696 (4)0.065 (2)
O40.8358 (3)0.2272 (15)0.8951 (3)0.0546 (18)
O50.7020 (3)0.5010 (12)0.7518 (3)0.0516 (17)
N10.7096 (3)0.0685 (14)0.7830 (3)0.0343 (15)
H10.71160.09340.76580.041*
C10.5969 (4)0.0340 (16)0.8513 (4)0.0345 (19)
C20.5642 (4)0.1938 (17)0.7856 (4)0.0372 (19)
H20.59010.32810.77050.045*
C30.4958 (4)0.1618 (17)0.7426 (5)0.0368 (19)
C40.4572 (4)0.038 (2)0.7634 (4)0.0384 (19)
C50.4888 (4)0.197 (2)0.8287 (5)0.0392 (19)
H50.46290.33010.84430.047*
C60.5576 (4)0.1620 (17)0.8710 (5)0.039 (2)
H60.57890.27540.91490.047*
C70.5016 (5)0.489 (2)0.6473 (6)0.058 (3)
H7A0.47120.58010.60000.088*
H7B0.52340.61840.68910.088*
H7C0.53760.39270.63260.088*
C80.3492 (4)0.264 (2)0.7364 (6)0.064 (3)
H8A0.30160.25580.69970.097*
H8B0.36990.43430.73010.097*
H8C0.34890.24590.79180.097*
C90.6713 (4)0.0682 (16)0.8965 (4)0.0359 (19)
H9A0.68400.25500.89270.043*
H9B0.67860.02890.95380.043*
C100.7194 (4)0.1063 (16)0.8672 (4)0.0345 (19)
H100.70710.29370.87430.041*
C110.7935 (4)0.0700 (19)0.9151 (4)0.0374 (19)
C120.9079 (4)0.215 (3)0.9399 (5)0.059 (3)
H12A0.93340.34260.91820.089*
H12B0.92530.03680.93600.089*
H12C0.91430.25650.99620.089*
C130.6978 (4)0.2648 (17)0.7294 (5)0.0364 (19)
C15A0.7231 (10)0.260 (5)0.6026 (9)0.044 (6)0.46 (2)
H15A0.76580.34760.62750.053*0.46 (2)
C16A0.7033 (8)0.194 (5)0.5219 (10)0.052 (7)0.46 (2)
H16A0.73390.23430.49240.062*0.46 (2)
C17A0.6407 (4)0.072 (2)0.4826 (5)0.054 (3)0.46 (2)
H17A0.62710.02910.42710.065*0.46 (2)
C18A0.5991 (10)0.017 (5)0.5305 (10)0.060 (7)0.46 (2)
H18A0.55520.06160.50500.072*0.46 (2)
C19A0.6163 (7)0.067 (5)0.6124 (9)0.049 (6)0.46 (2)
H19A0.58720.01860.64300.059*0.46 (2)
C140.6796 (4)0.1945 (15)0.6461 (4)0.0349 (18)
C15B0.6839 (12)0.376 (3)0.5891 (8)0.058 (6)0.54 (2)
H15B0.69990.54830.60660.070*0.54 (2)
C16B0.6663 (12)0.321 (3)0.5083 (9)0.071 (8)0.54 (2)
H16B0.67160.44960.47150.085*0.54 (2)
C17B0.6407 (4)0.072 (2)0.4826 (5)0.054 (3)0.54
H17B0.62830.03210.42700.065*0.54 (2)
C18B0.6327 (13)0.119 (4)0.5342 (7)0.070 (7)0.54 (2)
H18B0.61530.28950.51630.084*0.54 (2)
C19B0.6516 (13)0.046 (3)0.6141 (8)0.058 (7)0.54 (2)
H19B0.64460.17250.65060.070*0.54 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.059 (4)0.044 (4)0.062 (4)0.004 (3)0.015 (3)0.017 (3)
O20.037 (3)0.055 (4)0.063 (3)0.001 (3)0.016 (3)0.004 (3)
O30.053 (4)0.055 (5)0.073 (4)0.000 (3)0.000 (3)0.023 (4)
O40.040 (3)0.057 (5)0.065 (4)0.009 (3)0.014 (3)0.017 (4)
O50.090 (5)0.011 (4)0.058 (4)0.001 (3)0.029 (3)0.002 (2)
N10.048 (4)0.011 (3)0.042 (3)0.004 (3)0.012 (3)0.004 (3)
C10.037 (4)0.026 (5)0.047 (4)0.005 (3)0.022 (4)0.006 (4)
C20.047 (5)0.025 (5)0.045 (5)0.002 (4)0.022 (4)0.002 (3)
C30.039 (5)0.030 (5)0.042 (5)0.006 (3)0.015 (4)0.007 (4)
C40.030 (4)0.046 (5)0.044 (4)0.001 (4)0.018 (4)0.002 (4)
C50.038 (4)0.029 (5)0.055 (5)0.002 (4)0.022 (4)0.010 (4)
C60.042 (5)0.033 (5)0.046 (4)0.001 (4)0.019 (4)0.009 (4)
C70.065 (6)0.042 (7)0.074 (6)0.011 (5)0.030 (5)0.023 (5)
C80.034 (5)0.069 (8)0.096 (7)0.002 (5)0.029 (5)0.015 (6)
C90.049 (5)0.019 (5)0.045 (4)0.002 (3)0.023 (4)0.001 (3)
C100.047 (5)0.018 (5)0.037 (4)0.002 (3)0.010 (4)0.000 (3)
C110.045 (5)0.028 (5)0.041 (5)0.004 (4)0.017 (4)0.009 (4)
C120.040 (5)0.078 (8)0.063 (5)0.010 (5)0.021 (4)0.007 (6)
C130.036 (4)0.026 (5)0.047 (5)0.003 (4)0.012 (4)0.009 (4)
C15A0.043 (11)0.037 (14)0.062 (13)0.004 (11)0.031 (10)0.009 (10)
C16A0.032 (11)0.070 (18)0.060 (15)0.004 (12)0.024 (11)0.010 (13)
C17A0.055 (6)0.056 (7)0.053 (6)0.007 (5)0.018 (5)0.003 (5)
C18A0.052 (14)0.033 (16)0.085 (17)0.001 (11)0.009 (12)0.022 (12)
C19A0.035 (11)0.065 (16)0.045 (12)0.029 (13)0.009 (9)0.004 (11)
C140.038 (4)0.017 (4)0.050 (5)0.004 (3)0.014 (4)0.006 (4)
C15B0.075 (16)0.033 (12)0.072 (14)0.014 (12)0.030 (11)0.002 (10)
C16B0.071 (16)0.11 (2)0.028 (10)0.030 (15)0.014 (10)0.001 (11)
C17B0.055 (6)0.056 (7)0.053 (6)0.007 (5)0.018 (5)0.003 (5)
C18B0.110 (19)0.051 (15)0.039 (11)0.015 (15)0.011 (11)0.004 (10)
C19B0.077 (16)0.047 (15)0.043 (10)0.033 (12)0.008 (10)0.006 (9)
Geometric parameters (Å, °) top
O1—C31.365 (9)C9—H9A0.9900
O1—C71.426 (11)C9—H9B0.9900
O2—C41.355 (8)C10—C111.484 (10)
O2—C81.445 (12)C10—H101.0000
O3—C111.210 (10)C12—H12A0.9800
O4—C111.302 (10)C12—H12B0.9800
O4—C121.427 (9)C12—H12C0.9800
O5—C131.255 (11)C13—C141.439 (10)
N1—C131.338 (10)C15A—C141.380 (10)
N1—C101.442 (9)C15A—C16A1.387 (10)
N1—H10.8800C15A—H15A0.9500
C1—C61.386 (10)C16A—C17A1.386 (10)
C1—C21.395 (11)C16A—H16A0.9500
C1—C91.479 (10)C17A—C18A1.401 (10)
C2—C31.365 (10)C17A—H17A0.9500
C2—H20.9500C18A—C19A1.393 (10)
C3—C41.399 (11)C18A—H18A0.9500
C4—C51.382 (11)C19A—C141.391 (10)
C5—C61.370 (10)C19A—H19A0.9500
C5—H50.9500C14—C15B1.383 (10)
C6—H60.9500C14—C19B1.385 (10)
C7—H7A0.9800C15B—C16B1.378 (10)
C7—H7B0.9800C15B—H15B0.9500
C7—H7C0.9800C16B—H16B0.9500
C8—H8A0.9800C18B—C19B1.384 (10)
C8—H8B0.9800C18B—H18B0.9500
C8—H8C0.9800C19B—H19B0.9500
C9—C101.526 (10)
C3—O1—C7117.6 (6)C11—C10—H10107.2
C4—O2—C8116.9 (7)C9—C10—H10107.2
C11—O4—C12118.4 (7)O3—C11—O4121.6 (7)
C13—N1—C10123.9 (7)O3—C11—C10124.2 (8)
C13—N1—H1118.0O4—C11—C10114.2 (7)
C10—N1—H1118.0O4—C12—H12A109.5
C6—C1—C2117.5 (7)O4—C12—H12B109.5
C6—C1—C9121.5 (7)H12A—C12—H12B109.5
C2—C1—C9121.0 (7)O4—C12—H12C109.5
C3—C2—C1121.6 (7)H12A—C12—H12C109.5
C3—C2—H2119.2H12B—C12—H12C109.5
C1—C2—H2119.2O5—C13—N1120.7 (7)
O1—C3—C2124.0 (7)O5—C13—C14121.7 (7)
O1—C3—C4116.0 (7)N1—C13—C14117.6 (7)
C2—C3—C4119.9 (7)C14—C15A—C16A118.6 (15)
O2—C4—C5125.0 (8)C14—C15A—H15A120.7
O2—C4—C3115.8 (7)C16A—C15A—H15A120.7
C5—C4—C3119.1 (7)C17A—C16A—C15A122.7 (15)
C6—C5—C4120.1 (8)C17A—C16A—H16A118.6
C6—C5—H5120.0C15A—C16A—H16A118.6
C4—C5—H5120.0C16A—C17A—C18A115.0 (12)
C5—C6—C1121.8 (8)C16A—C17A—H17A122.5
C5—C6—H6119.1C18A—C17A—H17A122.5
C1—C6—H6119.1C19A—C18A—C17A125.7 (16)
O1—C7—H7A109.5C19A—C18A—H18A117.2
O1—C7—H7B109.5C17A—C18A—H18A117.2
H7A—C7—H7B109.5C14—C19A—C18A114.9 (15)
O1—C7—H7C109.5C14—C19A—H19A122.6
H7A—C7—H7C109.5C18A—C19A—H19A122.6
H7B—C7—H7C109.5C15A—C14—C19B103.8 (13)
O2—C8—H8A109.5C15B—C14—C19B113.8 (11)
O2—C8—H8B109.5C15A—C14—C19A123.0 (12)
H8A—C8—H8B109.5C15B—C14—C19A105.2 (13)
O2—C8—H8C109.5C15A—C14—C13120.1 (9)
H8A—C8—H8C109.5C15B—C14—C13121.2 (9)
H8B—C8—H8C109.5C19B—C14—C13124.8 (9)
C1—C9—C10114.0 (6)C19A—C14—C13116.9 (9)
C1—C9—H9A108.7C16B—C15B—C14123.8 (14)
C10—C9—H9A108.7C16B—C15B—H15B118.1
C1—C9—H9B108.7C14—C15B—H15B118.1
C10—C9—H9B108.7C15B—C16B—H16B121.0
H9A—C9—H9B107.6C19B—C18B—H18B122.3
N1—C10—C11110.5 (6)C18B—C19B—C14126.4 (14)
N1—C10—C9112.0 (6)C18B—C19B—H19B116.8
C11—C10—C9112.3 (6)C14—C19B—H19B116.8
N1—C10—H10107.2
C6—C1—C2—C30.8 (11)C9—C10—C11—O4176.0 (7)
C9—C1—C2—C3179.0 (7)C10—N1—C13—O57.9 (11)
C7—O1—C3—C25.5 (12)C10—N1—C13—C14171.6 (6)
C7—O1—C3—C4171.7 (8)C14—C15A—C16A—C17A2(3)
C1—C2—C3—O1178.2 (8)C15A—C16A—C17A—C18A1(3)
C1—C2—C3—C41.1 (12)C16A—C17A—C18A—C19A2(3)
C8—O2—C4—C54.8 (12)C17A—C18A—C19A—C143(3)
C8—O2—C4—C3177.7 (8)C16A—C15A—C14—C15B74 (2)
O1—C3—C4—O23.5 (11)C16A—C15A—C14—C19B36 (2)
C2—C3—C4—O2179.2 (7)C16A—C15A—C14—C19A0(3)
O1—C3—C4—C5178.9 (8)C16A—C15A—C14—C13178.6 (17)
C2—C3—C4—C51.5 (12)C18A—C19A—C14—C15A2(3)
O2—C4—C5—C6179.1 (8)C18A—C19A—C14—C15B39 (2)
C3—C4—C5—C61.7 (12)C18A—C19A—C14—C19B71 (2)
C4—C5—C6—C11.5 (12)C18A—C19A—C14—C13176.4 (16)
C2—C1—C6—C51.0 (11)O5—C13—C14—C15A65.0 (16)
C9—C1—C6—C5179.2 (7)N1—C13—C14—C15A115.6 (15)
C6—C1—C9—C1085.4 (9)O5—C13—C14—C15B17.4 (16)
C2—C1—C9—C1092.6 (9)N1—C13—C14—C15B163.1 (14)
C13—N1—C10—C11106.4 (8)O5—C13—C14—C19B157.3 (16)
C13—N1—C10—C9127.5 (8)N1—C13—C14—C19B22.2 (17)
C1—C9—C10—N156.0 (9)O5—C13—C14—C19A113.3 (14)
C1—C9—C10—C11178.8 (7)N1—C13—C14—C19A66.2 (14)
C12—O4—C11—O30.9 (13)C15A—C14—C15B—C16B80 (3)
C12—O4—C11—C10177.4 (7)C19B—C14—C15B—C16B4(3)
N1—C10—C11—O3123.6 (9)C19A—C14—C15B—C16B44 (3)
C9—C10—C11—O32.3 (11)C13—C14—C15B—C16B179.1 (18)
N1—C10—C11—O458.1 (9)C13—C14—C19B—C18B179.2 (19)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O5i0.882.072.924 (9)163
C2—H2···O5i0.952.553.412 (11)151
Symmetry codes: (i) x, y−1, z.
Table 1
Hydrogen-bond geometry (Å, °)
top
D—H···AD—HH···AD···AD—H···A
N1—H1···O5i0.882.072.924 (9)163
C2—H2···O5i0.952.553.412 (11)151
Symmetry codes: (i) x, y−1, z.
Acknowledgements top

The authors wish to thank Dr Hong Su of the Chemistry Department of the University of Cape Town for her assistance with the crystallographic data collection.

references
References top

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