(S)-1-Methoxy­carbonyl-2-(4-nitro­phen­yl)ethanaminium chloride

The title compound, C₁₀H₁₃N₂O₄⁺·Cl⁻, comprises a Cl⁻ anion and a protonated aminium cation. The crystal packing is stabilized by cation–anion N—H...Cl hydrogen bonds and N—H...O hydrogen bonds, building an infinite two-dimensional network parallel to the (001) plane. The S absolute configuration at the chiral center was deduced from the synthetic pathway and confirmed by the X-ray analysis.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.049
• wR factor = 0.112
• Data-to-parameter ratio = 17.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          5

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.40
           From the CIF: _reflns_number_total               2751
           Count of symmetry unique reflns         1492
           Completeness (_total/calc)            184.38%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1259
           Fraction of Friedel pairs measured     0.844
           Are heavy atom types Z>Si present        yes
PLAT791_ALERT_4_G Confirm the Absolute Configuration of C8     ...          S

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

α-Amino acid derivatives are important molecules due to their pharmacological properties. Recently, there has been an increased interest in the enantiomeric preparation of α-amino acid derivatives as precursors for the synthesis of novel biologically active compounds (Lucchese et al., (2007); Arki et al., (2004); Hauck et al., (2006); Azim et al., (2006); Dai et al., (2008)). Here we report the crystal structure of the title compound.

The title compound is built up from a Cl^- anion and a protonated amino group cation (Fig. 1). The nitro group and the benzene ring are nearly planar, they are only twisted to each other by a torsion angles of C2-C1-N1-O1 (2.1 (7)° ) and C6-C1-N1-O2 (4.4 (7)° ), and the methyl 2-aminopropanoate substituent group is a zig-zag chain.

The crystal packing is stabilized by cation-anion N—H···Cl H-bonds and N—H···O H-bonds building an infinite two-dimensional network developping parallel to the (0 0 1) plane.(Table 1, Fig. 2).

The S absolute configuration at C8 is deduced from the synthetic pathway and confirmed by the X-ray analyses.

Related literature

For details of α-amino acid derivatives as precursors for the synthesis of novel biologically active compounds, see: Lucchese et al. (2007); Arki et al. (2004); Hauck et al. (2006); Dai et al. (2008); Azim et al. (2006).

S2. Experimental

Under nitrogen protection, 2-amino-3-phenylpropanoic acid (30 mmol), nitric acid (50 mmol) and sulfuric acid (20 mmol) were added in a flask. The mixture was stirred at 110 °C for 3 h. The resulting solution was poured into ice water (100 mL), then filtered and washed with distilled water. The nitration amino acid was esterified with H₂SO₄ and CH₃OH at 110 °C for 12 h, the crude product was obtained by evaporated the solution, and then recrystallized with distilled water by adding 1 ml HCl to yield colorless block-like crystals, suitable for X-ray analysis.

S3. Refinement

All H atoms attached to C atoms and N atoms were fixed geometrically and treated as riding with C—H = 0.96 Å (methyl), 0.97 Å (methylene), 0.98 Å (methine), 0.93 Å (aromatic) and N—H = 0.89 Å with U_iso(H) = 1.2U_eq(C except methyl) or U_iso(H) = 1.5U_eq(N and methyl C).

Computing details

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Bruno et al., 2002); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. A view of the title compound with the atomic numbering scheme. Displacement ellipsoids were drawn at the 30% probability level. H atoms are represented as small spheres of arbitrary radii.
	Fig. 2. The crystal packing of the title compound viewed along the b axis and all hydrogen atoms not involved in hydrogen bonding (dashed lines) were omitted for clarity.

(S)-1-Methoxycarbonyl-2-(4-nitrophenyl)ethanaminium chloride

Crystal data

C10H13N2O4^+·Cl^−	F(000) = 272
Mr = 260.67	Dx = 1.416 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 1445 reflections
a = 4.825 (3) Å	θ = 2.4–27.5°
b = 8.426 (3) Å	µ = 0.32 mm^−1
c = 15.111 (9) Å	T = 298 K
β = 95.64 (4)°	Block, colourless
V = 611.4 (6) Å^3	0.25 × 0.18 × 0.17 mm
Z = 2

Data collection

Rigaku Mercury2 diffractometer	2751 independent reflections
Radiation source: fine-focus sealed tube	2077 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.038
Detector resolution: 13.6612 pixels mm^-1	θmax = 27.4°, θmin = 2.7°
ω scans	h = −6→6
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	k = −10→10
Tmin = 0.931, Tmax = 0.942	l = −19→19
6215 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.048	H-atom parameters constrained
wR(F^2) = 0.112	w = 1/[σ^2(Fo^2) + (0.0476P)^2 + 0.0855P] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max < 0.001
2751 reflections	Δρmax = 0.30 e Å^−3
154 parameters	Δρmin = −0.17 e Å^−3
1 restraint	Absolute structure: Flack (1983), 1259 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.03 (9)

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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 (Ų)

	x	y	z	Uiso*/Ueq
Cl1	0.98552 (15)	0.75535 (11)	0.54873 (5)	0.0499 (2)
O3	0.8079 (4)	0.7690 (3)	0.30131 (12)	0.0483 (5)
C9	0.6109 (5)	0.7495 (4)	0.35535 (16)	0.0362 (6)
O4	0.4684 (5)	0.8525 (3)	0.38126 (14)	0.0498 (6)
C8	0.5762 (6)	0.5766 (3)	0.37686 (18)	0.0353 (6)
H8A	0.7584	0.5243	0.3803	0.042*
N2	0.4629 (6)	0.5646 (3)	0.46458 (15)	0.0448 (6)
H11A	0.5788	0.6120	0.5058	0.067*
H11B	0.4447	0.4629	0.4787	0.067*
H11C	0.2973	0.6119	0.4617	0.067*
C4	0.4967 (6)	0.4821 (4)	0.21766 (19)	0.0400 (7)
C7	0.3780 (7)	0.4943 (4)	0.3058 (2)	0.0439 (7)
H7A	0.3369	0.3885	0.3262	0.053*
H7B	0.2044	0.5530	0.2980	0.053*
C1	0.7171 (8)	0.4557 (4)	0.0577 (2)	0.0493 (8)
C2	0.8081 (8)	0.3560 (5)	0.1245 (2)	0.0576 (9)
H2C	0.9440	0.2805	0.1165	0.069*
C3	0.6962 (7)	0.3682 (4)	0.2046 (2)	0.0512 (8)
H3A	0.7551	0.2991	0.2506	0.061*
C5	0.4107 (7)	0.5812 (4)	0.1485 (2)	0.0530 (9)
H5A	0.2761	0.6576	0.1561	0.064*
C6	0.5198 (8)	0.5697 (5)	0.0674 (2)	0.0612 (10)
H6A	0.4609	0.6375	0.0207	0.073*
N1	0.8330 (9)	0.4439 (5)	−0.0288 (2)	0.0722 (10)
O1	1.0166 (8)	0.3463 (5)	−0.0366 (2)	0.1027 (12)
O2	0.7365 (9)	0.5296 (5)	−0.0890 (2)	0.1057 (12)
C10	0.8487 (10)	0.9318 (4)	0.2717 (3)	0.0691 (11)
H10A	0.9951	0.9340	0.2331	0.104*
H10B	0.8984	0.9983	0.3224	0.104*
H10C	0.6794	0.9702	0.2402	0.104*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0520 (4)	0.0476 (4)	0.0505 (4)	0.0037 (4)	0.0075 (3)	−0.0092 (4)
O3	0.0588 (12)	0.0420 (12)	0.0475 (11)	−0.0084 (12)	0.0217 (10)	0.0009 (12)
C9	0.0410 (14)	0.0359 (14)	0.0315 (12)	−0.0017 (16)	0.0027 (11)	−0.0029 (15)
O4	0.0582 (14)	0.0403 (12)	0.0521 (13)	0.0093 (11)	0.0123 (11)	0.0021 (11)
C8	0.0429 (16)	0.0342 (15)	0.0303 (14)	0.0008 (13)	0.0109 (12)	0.0018 (12)
N2	0.0599 (17)	0.0372 (14)	0.0390 (14)	−0.0001 (13)	0.0135 (12)	0.0005 (12)
C4	0.0466 (17)	0.0353 (15)	0.0389 (16)	−0.0111 (13)	0.0074 (14)	−0.0071 (13)
C7	0.0428 (17)	0.0444 (18)	0.0460 (17)	−0.0076 (14)	0.0114 (14)	−0.0031 (15)
C1	0.058 (2)	0.056 (2)	0.0364 (17)	−0.0125 (17)	0.0129 (15)	−0.0138 (15)
C2	0.060 (2)	0.062 (2)	0.052 (2)	0.0040 (19)	0.0099 (17)	−0.0160 (19)
C3	0.067 (2)	0.0434 (18)	0.0431 (18)	−0.0007 (17)	0.0073 (16)	−0.0024 (15)
C5	0.060 (2)	0.053 (2)	0.0465 (19)	0.0070 (17)	0.0083 (16)	0.0000 (17)
C6	0.078 (3)	0.064 (2)	0.0403 (19)	−0.006 (2)	0.0023 (18)	0.0038 (18)
N1	0.085 (3)	0.089 (3)	0.0451 (19)	−0.023 (2)	0.0180 (17)	−0.021 (2)
O1	0.094 (2)	0.141 (3)	0.078 (2)	0.008 (2)	0.0345 (19)	−0.035 (2)
O2	0.155 (3)	0.121 (3)	0.0465 (16)	−0.005 (3)	0.0353 (19)	0.0011 (19)
C10	0.090 (3)	0.052 (2)	0.068 (2)	−0.011 (2)	0.022 (2)	0.013 (2)

Geometric parameters (Å, º)

O3—C9	1.323 (3)	C1—C2	1.353 (5)
O3—C10	1.462 (4)	C1—C6	1.371 (5)
C9—O4	1.196 (4)	C1—N1	1.475 (4)
C9—C8	1.506 (4)	C2—C3	1.377 (4)
C8—N2	1.486 (3)	C2—H2C	0.9300
C8—C7	1.532 (4)	C3—H3A	0.9300
C8—H8A	0.9800	C5—C6	1.384 (5)
N2—H11A	0.8900	C5—H5A	0.9300
N2—H11B	0.8900	C6—H6A	0.9300
N2—H11C	0.8900	N1—O2	1.217 (5)
C4—C5	1.370 (4)	N1—O1	1.223 (5)
C4—C3	1.387 (5)	C10—H10A	0.9600
C4—C7	1.505 (4)	C10—H10B	0.9600
C7—H7A	0.9700	C10—H10C	0.9600
C7—H7B	0.9700
C9—O3—C10	115.6 (3)	C2—C1—C6	122.2 (3)
O4—C9—O3	125.7 (3)	C2—C1—N1	119.8 (4)
O4—C9—C8	123.5 (3)	C6—C1—N1	118.0 (4)
O3—C9—C8	110.8 (3)	C1—C2—C3	118.9 (3)
N2—C8—C9	108.4 (2)	C1—C2—H2C	120.6
N2—C8—C7	109.6 (2)	C3—C2—H2C	120.6
C9—C8—C7	111.2 (2)	C2—C3—C4	121.0 (3)
N2—C8—H8A	109.2	C2—C3—H3A	119.5
C9—C8—H8A	109.2	C4—C3—H3A	119.5
C7—C8—H8A	109.2	C4—C5—C6	121.4 (3)
C8—N2—H11A	109.5	C4—C5—H5A	119.3
C8—N2—H11B	109.5	C6—C5—H5A	119.3
H11A—N2—H11B	109.5	C1—C6—C5	118.2 (3)
C8—N2—H11C	109.5	C1—C6—H6A	120.9
H11A—N2—H11C	109.5	C5—C6—H6A	120.9
H11B—N2—H11C	109.5	O2—N1—O1	123.7 (4)
C5—C4—C3	118.4 (3)	O2—N1—C1	118.1 (4)
C5—C4—C7	121.4 (3)	O1—N1—C1	118.2 (4)
C3—C4—C7	120.2 (3)	O3—C10—H10A	109.5
C4—C7—C8	112.7 (3)	O3—C10—H10B	109.5
C4—C7—H7A	109.1	H10A—C10—H10B	109.5
C8—C7—H7A	109.1	O3—C10—H10C	109.5
C4—C7—H7B	109.1	H10A—C10—H10C	109.5
C8—C7—H7B	109.1	H10B—C10—H10C	109.5
H7A—C7—H7B	107.8
C10—O3—C9—O4	−0.3 (4)	C1—C2—C3—C4	−1.1 (5)
C10—O3—C9—C8	176.6 (3)	C5—C4—C3—C2	0.9 (5)
O4—C9—C8—N2	−29.2 (4)	C7—C4—C3—C2	−179.7 (3)
O3—C9—C8—N2	153.9 (2)	C3—C4—C5—C6	−0.4 (5)
O4—C9—C8—C7	91.4 (3)	C7—C4—C5—C6	−179.9 (3)
O3—C9—C8—C7	−85.5 (3)	C2—C1—C6—C5	−0.4 (6)
C5—C4—C7—C8	−103.2 (4)	N1—C1—C6—C5	−180.0 (3)
C3—C4—C7—C8	77.3 (4)	C4—C5—C6—C1	0.2 (5)
N2—C8—C7—C4	−172.3 (2)	C2—C1—N1—O2	176.2 (4)
C9—C8—C7—C4	67.8 (3)	C6—C1—N1—O2	−4.2 (5)
C6—C1—C2—C3	0.8 (6)	C2—C1—N1—O1	−2.3 (5)
N1—C1—C2—C3	−179.6 (3)	C6—C1—N1—O1	177.3 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H11B···O4^i	0.89	2.31	2.929 (4)	127
N2—H11B···Cl1^i	0.89	2.71	3.380 (3)	133
N2—H11C···Cl1^ii	0.89	2.42	3.175 (3)	143
N2—H11A···Cl1	0.89	2.34	3.151 (3)	151

Symmetry codes: (i) −x+1, y−1/2, −z+1; (ii) x−1, y, z.