supplementary materials


HTML versionpdf versioncif file3d viewstructure factorssupplementary materialsCIF check reportsimilar papers Open access

Acta Cryst. (2009). E65, o662    [ doi:10.1107/S1600536809007119 ]

3-Methyl-2-propionamidobutanoic acid

B. M. Yamin and E. A. Othman

Abstract top

The reaction of propionyl isothiocyanate with valine was found to give the title compound, C8H15NO3, instead of the expected thiourea product. The whole molecule is non-planar and the carbonyl group is cis to the methylbutanoic acid group across the C-N bond. Intermolecular O-H...O and N-H...O hydrogen bonds build up a two-dimensional network developing parallel to (100).

Comment top

The carbonoyl isothiocyanate is a well known intermediate for the synthesis of carbonoylthiourea deriatives. However, some carbonoyl isothiocyanates such as propionyl isothiocyanate was reactive enough to give N-propionylthiourea (Yamin & Othman,2008) after sitrring for about 1 h. In the present study, the reaction of propionyl isothiocyanate with valine did not give the expected thiourea derivative but instead the 3-methyl-2-propionamidobutanoic acid (I), thus indicating a nucleophilic substitution of the isothiocyanato group by the amino group of the amino acid.

The molecule adopts cis configuration with respect to the position of the 3-methylbutanoic acid group relative to the carbonyl O3 atom across the C3—N1 bond. The bond lengths and angles are within normal ranges (Allen et al., 1987). The acetamide [O3/N1/C2/C3/C4 (A)] and acetate [O1/O2/C4/C8 (B)] fragments are essentially planar with maximum deviation of 0.011 (2)Å for atom N1. The compound has a stereogenic center at C4 but the space group is centrosymmetric so the molecule exists as a racemate (R/S).

O—H···O and N—H···O intermolecular hydrogen bonds build up a two dimensional network with a corrugated iron shape developping parallel to the (1 0 0) plane.

Related literature top

For the crystal structure of N-propionylthiourea, see: Yamin & Othman (2008). For bond-length data, see: Allen et al. (1987).

Experimental top

A solution of propionylisothiocyanate (1.15 g, 0.01 mol) in 30 ml acetone was added into a flask containing 30 ml acetone solution of valine (1.17 g, 0.01 mol). The mixture was refluxed for 5 h. The solution was filtered and left to evaporate at room temperature. The colourless solid were obtained after one day of evaporation(yield 85%, m.p 475.1–476.3 K)

Refinement top

H atoms attached to carbon atoms were positioned geometrically and treated as riding on their parent atoms with C—H= 0.96–0.98 Å and Uiso(H)= xUeq(C) where x=1.5 for CH3 group and 1.2 for CH2 and CH groups. The hydrogen atoms attached to nitrogen and oxygen atoms were located from Fourier difference map and refined isotropically,

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Burnett & Johnson, 1996), ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008), PARST (Nardelli, 1995) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The nolecular structure of (I) with the atom-labeling scheme. Ellipsoids are drawn at the 30% probability level. H atoms are represented as small spheres of arbitrary radii. The enantiomer represented has S configuration.
[Figure 2] Fig. 2. Partial packing view of I showing the H bonds network. Hydrogen bonds are shown as dashed lines. [Symmetry codes: (i) -x+1, -y, -z; (ii) x, -y+1/2, z-1/2]
3-Methyl-2-propionamidobutanoic acid top
Crystal data top
C8H15NO3F(000) = 376
Mr = 173.21Dx = 1.131 Mg m−3
Monoclinic, P21/cMelting point: 475.5 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 9.477 (3) ÅCell parameters from 1183 reflections
b = 8.633 (2) Åθ = 2.2–25.5°
c = 12.766 (3) ŵ = 0.09 mm−1
β = 103.123 (6)°T = 298 K
V = 1017.2 (5) Å3Block, colourless
Z = 40.49 × 0.33 × 0.18 mm
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer		1887 independent reflections
Radiation source: fine-focus sealed tube1262 reflections with I > 2σ(I)
graphiteRint = 0.024
Detector resolution: 83.66 pixels mm-1θmax = 25.5°, θmin = 2.2°
ω scansh = −10→11
Absorption correction: multi-scan
(SADABS; Bruker, 2000)		k = −10→10
Tmin = 0.959, Tmax = 0.984l = −15→8
5313 measured reflections
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)] = 0.059Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.167H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.0815P)2 + 0.2058P]
where P = (Fo2 + 2Fc2)/3
1887 reflections(Δ/σ)max = 0.001
117 parametersΔρmax = 0.24 e Å−3
2 restraintsΔρmin = −0.15 e Å−3
Crystal data top
C8H15NO3V = 1017.2 (5) Å3
Mr = 173.21Z = 4
Monoclinic, P21/cMo Kα radiation
a = 9.477 (3) ŵ = 0.09 mm−1
b = 8.633 (2) ÅT = 298 K
c = 12.766 (3) Å0.49 × 0.33 × 0.18 mm
β = 103.123 (6)°
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer		1887 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2000)		1262 reflections with I > 2σ(I)
Tmin = 0.959, Tmax = 0.984Rint = 0.024
5313 measured reflectionsθmax = 25.5°
Refinement top
R[F2 > 2σ(F2)] = 0.059H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.167Δρmax = 0.24 e Å−3
S = 1.04Δρmin = −0.15 e Å−3
1887 reflectionsAbsolute structure: ?
117 parametersFlack parameter: ?
2 restraintsRogers parameter: ?
Special details top

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*/Ueq
O10.58011 (17)0.1690 (2)−0.01032 (13)0.0706 (6)
O20.80400 (19)0.2599 (2)0.01281 (15)0.0808 (6)
H2C0.775 (3)0.309 (3)−0.0430 (16)0.115 (12)*
O30.7243 (2)0.0786 (2)0.33764 (14)0.0835 (6)
N10.6507 (2)−0.0073 (2)0.17012 (15)0.0523 (5)
H1D0.5834 (18)−0.050 (2)0.1230 (15)0.058 (7)*
C10.3968 (4)0.0265 (4)0.3214 (3)0.1079 (12)
H1A0.3188−0.03400.33660.162*
H1B0.36020.09280.26100.162*
H1C0.43900.08840.38300.162*
C20.5071 (3)−0.0769 (3)0.2963 (2)0.0776 (8)
H2A0.4623−0.14110.23540.093*
H2B0.5414−0.14490.35720.093*
C30.6357 (3)0.0049 (3)0.27028 (19)0.0573 (6)
C40.7670 (2)0.0664 (3)0.13158 (16)0.0509 (6)
H4A0.81990.13310.18940.061*
C50.8765 (3)−0.0509 (3)0.1042 (2)0.0684 (7)
H5A0.95120.00830.07970.082*
C60.9513 (3)−0.1423 (4)0.2037 (3)0.1062 (11)
H6A1.0190−0.21380.18470.159*
H6B0.8802−0.19830.23130.159*
H6C1.0020−0.07210.25760.159*
C70.8066 (3)−0.1595 (4)0.0136 (3)0.0905 (9)
H7A0.8782−0.2296−0.00120.136*
H7B0.7664−0.1002−0.04980.136*
H7C0.7309−0.21730.03450.136*
C80.7047 (2)0.1683 (2)0.03739 (16)0.0517 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0574 (11)0.0732 (12)0.0697 (11)−0.0047 (8)−0.0100 (8)0.0117 (8)
O20.0616 (11)0.1039 (14)0.0740 (13)−0.0103 (10)0.0094 (9)0.0375 (11)
O30.1026 (15)0.0943 (14)0.0564 (11)−0.0129 (11)0.0237 (10)−0.0233 (10)
N10.0491 (11)0.0648 (12)0.0422 (10)−0.0072 (9)0.0087 (8)−0.0021 (9)
C10.088 (2)0.088 (2)0.162 (4)−0.0066 (18)0.057 (2)0.001 (2)
C20.097 (2)0.0680 (17)0.0806 (18)0.0026 (15)0.0463 (16)0.0076 (13)
C30.0682 (15)0.0526 (13)0.0538 (14)0.0077 (12)0.0194 (12)−0.0015 (11)
C40.0442 (12)0.0609 (13)0.0444 (12)−0.0073 (10)0.0035 (9)0.0038 (10)
C50.0495 (13)0.0817 (17)0.0755 (17)0.0093 (12)0.0172 (12)0.0186 (14)
C60.082 (2)0.123 (3)0.110 (2)0.036 (2)0.0132 (17)0.040 (2)
C70.091 (2)0.087 (2)0.101 (2)0.0129 (17)0.0370 (17)−0.0154 (17)
C80.0533 (13)0.0564 (13)0.0438 (12)−0.0049 (11)0.0077 (10)−0.0016 (10)
Geometric parameters (Å, °) top
O1—C81.200 (2)C2—H2B0.9700
O2—C81.320 (3)C4—C81.499 (3)
O2—H2C0.821 (10)C4—C51.546 (3)
O3—C31.233 (3)C4—H4A0.9800
N1—C31.322 (3)C5—C71.519 (4)
N1—C41.453 (3)C5—C61.526 (4)
N1—H1D0.855 (10)C5—H5A0.9800
C1—C21.464 (4)C6—H6A0.9600
C1—H1A0.9600C6—H6B0.9600
C1—H1B0.9600C6—H6C0.9600
C1—H1C0.9600C7—H7A0.9600
C2—C31.509 (3)C7—H7B0.9600
C2—H2A0.9700C7—H7C0.9600
C8—O2—H2C114 (2)C8—C4—H4A107.5
C3—N1—C4123.30 (19)C5—C4—H4A107.5
C3—N1—H1D119.2 (16)C7—C5—C6110.8 (3)
C4—N1—H1D117.0 (16)C7—C5—C4112.18 (19)
C2—C1—H1A109.5C6—C5—C4111.1 (2)
C2—C1—H1B109.5C7—C5—H5A107.5
H1A—C1—H1B109.5C6—C5—H5A107.5
C2—C1—H1C109.5C4—C5—H5A107.5
H1A—C1—H1C109.5C5—C6—H6A109.5
H1B—C1—H1C109.5C5—C6—H6B109.5
C1—C2—C3114.5 (2)H6A—C6—H6B109.5
C1—C2—H2A108.6C5—C6—H6C109.5
C3—C2—H2A108.6H6A—C6—H6C109.5
C1—C2—H2B108.6H6B—C6—H6C109.5
C3—C2—H2B108.6C5—C7—H7A109.5
H2A—C2—H2B107.6C5—C7—H7B109.5
O3—C3—N1120.7 (2)H7A—C7—H7B109.5
O3—C3—C2122.9 (2)C5—C7—H7C109.5
N1—C3—C2116.4 (2)H7A—C7—H7C109.5
N1—C4—C8109.76 (17)H7B—C7—H7C109.5
N1—C4—C5112.93 (19)O1—C8—O2123.3 (2)
C8—C4—C5111.44 (18)O1—C8—C4125.0 (2)
N1—C4—H4A107.5O2—C8—C4111.72 (19)
C4—N1—C3—O3−1.7 (3)C8—C4—C5—C7−61.5 (3)
C4—N1—C3—C2179.0 (2)N1—C4—C5—C6−62.0 (3)
C1—C2—C3—O368.0 (4)C8—C4—C5—C6173.9 (2)
C1—C2—C3—N1−112.7 (3)N1—C4—C8—O1−11.6 (3)
C3—N1—C4—C8−123.5 (2)C5—C4—C8—O1114.2 (3)
C3—N1—C4—C5111.5 (2)N1—C4—C8—O2167.87 (19)
N1—C4—C5—C762.6 (3)C5—C4—C8—O2−66.3 (2)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1D···O1i0.86 (2)2.13 (2)2.978 (3)177 (2)
O2—H2C···O3ii0.82 (2)1.78 (2)2.598 (3)176 (2)
Symmetry codes: (i) −x+1, −y, −z; (ii) x, −y+1/2, z−1/2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1D···O1i0.86 (2)2.13 (2)2.978 (3)177 (2)
O2—H2C···O3ii0.82 (2)1.78 (2)2.598 (3)176 (2)
Symmetry codes: (i) −x+1, −y, −z; (ii) x, −y+1/2, z−1/2.
Acknowledgements top

The authors thank the Ministry of Higher Education of Malaysia for a research grant (UKM-GUP-NBT-08–27–110) and a graduate assistentship (UKM-OUP-NBT-27–144) to EAO. They also thank Universiti Kebangsaan Malaysia for the facilities.

references
References top

Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.

Bruker (2000). SADABS, SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.

Burnett, M. N. & Johnson, C. K. (1996). ORTEPIII. Report ORNL-6895. Oak Ridge National Laboratory, Tennessee, USA.

Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.

Nardelli, M. (1995). J. Appl. Cryst. 28, 659.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Spek, A. L. (2009). Acta Cryst. D65, 148–155.

Yamin, B. M. & Othman, E. A. (2008). Acta Cryst. E64, o313.