3-Methyl-2-propionamido­butanoic acid

Yamin, B.M.; Othman, E.A.

doi:10.1107/S1600536809007119

organic compounds

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ISSN: 2056-9890

Volume 65| Part 4| April 2009| Page o662

doi:10.1107/S1600536809007119

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3-Methyl-2-propionamidobutanoic acid

Bohari M. Yamin ^a and Eliyanti A. Othman ^a ^*

^aSchool of Chemical Sciences and Food Technology, Universiti Kebangsaan Malaysia, UKM 43500 Bangi Selangor, Malaysia
^*Correspondence e-mail: eliyanti84@yahoo.com

(Received 21 January 2009; accepted 26 February 2009; online 6 March 2009)

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).

Related literature

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

Experimental

Crystal data

C₈H₁₅NO₃
M_r = 173.21
Monoclinic, P 2₁ /c
a = 9.477 (3) Å
b = 8.633 (2) Å
c = 12.766 (3) Å
β = 103.123 (6)°
V = 1017.2 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 298 K
0.49 × 0.33 × 0.18 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2000 ) T_min = 0.959, T_max = 0.984
5313 measured reflections
1887 independent reflections
1262 reflections with I > 2σ(I)
R_int = 0.024

Refinement

R[F² > 2σ(F²)] = 0.059
wR(F²) = 0.167
S = 1.04
1887 reflections
117 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.15 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1D⋯O1ⁱ	0.855 (18)	2.125 (18)	2.978 (3)	176.6 (16)
O2—H2C⋯O3ⁱⁱ	0.82 (2)	1.78 (2)	2.598 (3)	176 (2)
Symmetry codes: (i) -x+1, -y, -z; (ii) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; 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, PARST (Nardelli, 1995 ) and PLATON.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809007119/dn2429sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809007119/dn2429Isup2.hkl

checkCIF report

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)

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

	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.
	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

C₈H₁₅NO₃	F(000) = 376
M_r = 173.21	D_x = 1.131 Mg m⁻³
Monoclinic, P2₁/c	Melting point: 475.5 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 9.477 (3) Å	Cell parameters from 1183 reflections
b = 8.633 (2) Å	θ = 2.2–25.5°
c = 12.766 (3) Å	µ = 0.09 mm⁻¹
β = 103.123 (6)°	T = 298 K
V = 1017.2 (5) Å³	Block, colourless
Z = 4	0.49 × 0.33 × 0.18 mm

Data collection top

Bruker SMART APEX CCD area-detector diffractometer	1887 independent reflections
Radiation source: fine-focus sealed tube	1262 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.024
Detector resolution: 83.66 pixels mm^-1	θ_max = 25.5°, θ_min = 2.2°
ω scans	h = −10→11
Absorption correction: multi-scan (SADABS; Bruker, 2000)	k = −10→10
T_min = 0.959, T_max = 0.984	l = −15→8
5313 measured reflections

Refinement top

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)] = 0.059	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.167	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ²(F_o²) + (0.0815P)² + 0.2058P] where P = (F_o² + 2F_c²)/3
1887 reflections	(Δ/σ)_max = 0.001
117 parameters	Δρ_max = 0.24 e Å⁻³
2 restraints	Δρ_min = −0.15 e Å⁻³

Crystal data top

C₈H₁₅NO₃	V = 1017.2 (5) Å³
M_r = 173.21	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 9.477 (3) Å	µ = 0.09 mm⁻¹
b = 8.633 (2) Å	T = 298 K
c = 12.766 (3) Å	0.49 × 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)
T_min = 0.959, T_max = 0.984	R_int = 0.024
5313 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.059	2 restraints
wR(F²) = 0.167	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	Δρ_max = 0.24 e Å⁻³
1887 reflections	Δρ_min = −0.15 e Å⁻³
117 parameters

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

	x	y	z	U_iso*/U_eq
O1	0.58011 (17)	0.1690 (2)	−0.01032 (13)	0.0706 (6)
O2	0.80400 (19)	0.2599 (2)	0.01281 (15)	0.0808 (6)
H2C	0.775 (3)	0.309 (3)	−0.0430 (16)	0.115 (12)*
O3	0.7243 (2)	0.0786 (2)	0.33764 (14)	0.0835 (6)
N1	0.6507 (2)	−0.0073 (2)	0.17012 (15)	0.0523 (5)
H1D	0.5834 (18)	−0.050 (2)	0.1230 (15)	0.058 (7)*
C1	0.3968 (4)	0.0265 (4)	0.3214 (3)	0.1079 (12)
H1A	0.3188	−0.0340	0.3366	0.162*
H1B	0.3602	0.0928	0.2610	0.162*
H1C	0.4390	0.0884	0.3830	0.162*
C2	0.5071 (3)	−0.0769 (3)	0.2963 (2)	0.0776 (8)
H2A	0.4623	−0.1411	0.2354	0.093*
H2B	0.5414	−0.1449	0.3572	0.093*
C3	0.6357 (3)	0.0049 (3)	0.27028 (19)	0.0573 (6)
C4	0.7670 (2)	0.0664 (3)	0.13158 (16)	0.0509 (6)
H4A	0.8199	0.1331	0.1894	0.061*
C5	0.8765 (3)	−0.0509 (3)	0.1042 (2)	0.0684 (7)
H5A	0.9512	0.0083	0.0797	0.082*
C6	0.9513 (3)	−0.1423 (4)	0.2037 (3)	0.1062 (11)
H6A	1.0190	−0.2138	0.1847	0.159*
H6B	0.8802	−0.1983	0.2313	0.159*
H6C	1.0020	−0.0721	0.2576	0.159*
C7	0.8066 (3)	−0.1595 (4)	0.0136 (3)	0.0905 (9)
H7A	0.8782	−0.2296	−0.0012	0.136*
H7B	0.7664	−0.1002	−0.0498	0.136*
H7C	0.7309	−0.2173	0.0345	0.136*
C8	0.7047 (2)	0.1683 (2)	0.03739 (16)	0.0517 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0574 (11)	0.0732 (12)	0.0697 (11)	−0.0047 (8)	−0.0100 (8)	0.0117 (8)
O2	0.0616 (11)	0.1039 (14)	0.0740 (13)	−0.0103 (10)	0.0094 (9)	0.0375 (11)
O3	0.1026 (15)	0.0943 (14)	0.0564 (11)	−0.0129 (11)	0.0237 (10)	−0.0233 (10)
N1	0.0491 (11)	0.0648 (12)	0.0422 (10)	−0.0072 (9)	0.0087 (8)	−0.0021 (9)
C1	0.088 (2)	0.088 (2)	0.162 (4)	−0.0066 (18)	0.057 (2)	0.001 (2)
C2	0.097 (2)	0.0680 (17)	0.0806 (18)	0.0026 (15)	0.0463 (16)	0.0076 (13)
C3	0.0682 (15)	0.0526 (13)	0.0538 (14)	0.0077 (12)	0.0194 (12)	−0.0015 (11)
C4	0.0442 (12)	0.0609 (13)	0.0444 (12)	−0.0073 (10)	0.0035 (9)	0.0038 (10)
C5	0.0495 (13)	0.0817 (17)	0.0755 (17)	0.0093 (12)	0.0172 (12)	0.0186 (14)
C6	0.082 (2)	0.123 (3)	0.110 (2)	0.036 (2)	0.0132 (17)	0.040 (2)
C7	0.091 (2)	0.087 (2)	0.101 (2)	0.0129 (17)	0.0370 (17)	−0.0154 (17)
C8	0.0533 (13)	0.0564 (13)	0.0438 (12)	−0.0049 (11)	0.0077 (10)	−0.0016 (10)

Geometric parameters (Å, º) top

O1—C8	1.200 (2)	C2—H2B	0.9700
O2—C8	1.320 (3)	C4—C8	1.499 (3)
O2—H2C	0.821 (10)	C4—C5	1.546 (3)
O3—C3	1.233 (3)	C4—H4A	0.9800
N1—C3	1.322 (3)	C5—C7	1.519 (4)
N1—C4	1.453 (3)	C5—C6	1.526 (4)
N1—H1D	0.855 (10)	C5—H5A	0.9800
C1—C2	1.464 (4)	C6—H6A	0.9600
C1—H1A	0.9600	C6—H6B	0.9600
C1—H1B	0.9600	C6—H6C	0.9600
C1—H1C	0.9600	C7—H7A	0.9600
C2—C3	1.509 (3)	C7—H7B	0.9600
C2—H2A	0.9700	C7—H7C	0.9600

C8—O2—H2C	114 (2)	C8—C4—H4A	107.5
C3—N1—C4	123.30 (19)	C5—C4—H4A	107.5
C3—N1—H1D	119.2 (16)	C7—C5—C6	110.8 (3)
C4—N1—H1D	117.0 (16)	C7—C5—C4	112.18 (19)
C2—C1—H1A	109.5	C6—C5—C4	111.1 (2)
C2—C1—H1B	109.5	C7—C5—H5A	107.5
H1A—C1—H1B	109.5	C6—C5—H5A	107.5
C2—C1—H1C	109.5	C4—C5—H5A	107.5
H1A—C1—H1C	109.5	C5—C6—H6A	109.5
H1B—C1—H1C	109.5	C5—C6—H6B	109.5
C1—C2—C3	114.5 (2)	H6A—C6—H6B	109.5
C1—C2—H2A	108.6	C5—C6—H6C	109.5
C3—C2—H2A	108.6	H6A—C6—H6C	109.5
C1—C2—H2B	108.6	H6B—C6—H6C	109.5
C3—C2—H2B	108.6	C5—C7—H7A	109.5
H2A—C2—H2B	107.6	C5—C7—H7B	109.5
O3—C3—N1	120.7 (2)	H7A—C7—H7B	109.5
O3—C3—C2	122.9 (2)	C5—C7—H7C	109.5
N1—C3—C2	116.4 (2)	H7A—C7—H7C	109.5
N1—C4—C8	109.76 (17)	H7B—C7—H7C	109.5
N1—C4—C5	112.93 (19)	O1—C8—O2	123.3 (2)
C8—C4—C5	111.44 (18)	O1—C8—C4	125.0 (2)
N1—C4—H4A	107.5	O2—C8—C4	111.72 (19)

C4—N1—C3—O3	−1.7 (3)	C8—C4—C5—C7	−61.5 (3)
C4—N1—C3—C2	179.0 (2)	N1—C4—C5—C6	−62.0 (3)
C1—C2—C3—O3	68.0 (4)	C8—C4—C5—C6	173.9 (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—O1	114.2 (3)
C3—N1—C4—C5	111.5 (2)	N1—C4—C8—O2	167.87 (19)
N1—C4—C5—C7	62.6 (3)	C5—C4—C8—O2	−66.3 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1D···O1ⁱ	0.86 (2)	2.13 (2)	2.978 (3)	177 (2)
O2—H2C···O3ⁱⁱ	0.82 (2)	1.78 (2)	2.598 (3)	176 (2)

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

Experimental details

Crystal data
Chemical formula	C₈H₁₅NO₃
M_r	173.21
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	298
a, b, c (Å)	9.477 (3), 8.633 (2), 12.766 (3)
β (°)	103.123 (6)
V (Å³)	1017.2 (5)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.49 × 0.33 × 0.18

Data collection
Diffractometer	Bruker SMART APEX CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2000)
T_min, T_max	0.959, 0.984
No. of measured, independent and observed [I > 2σ(I)] reflections	5313, 1887, 1262
R_int	0.024
(sin θ/λ)_max (Å⁻¹)	0.606

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.059, 0.167, 1.04
No. of reflections	1887
No. of parameters	117
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.24, −0.15

Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 2008), ORTEPIII (Burnett & Johnson, 1996), ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2009), SHELXL97 (Sheldrick, 2008), PARST (Nardelli, 1995) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1D···O1ⁱ	0.855 (18)	2.125 (18)	2.978 (3)	176.6 (16)
O2—H2C···O3ⁱⁱ	0.82 (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

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

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