N-(β-Carb­oxy­eth­yl)-α-isoleucine

Nehls, I.; Hanebeck, O.; Becker, R.; Emmerling, F.

doi:10.1107/S160053681205146X

organic compounds

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ISSN: 2056-9890

Volume 69| Part 2| February 2013| Pages o172-o173

doi:10.1107/S160053681205146X

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N-(β-Carboxyethyl)-α-isoleucine

Irene Nehls,^a Olaf Hanebeck,^b Roland Becker ^a and Franziska Emmerling ^a ^*

^aFederal Institute for Materials Research and Testing (BAM), Richard-Willstaetter-Strasse 11, D-12489 Berlin, Germany, and ^bSGS Institut Fresenius GmbH, Tegeler Weg 33, D-10589 Berlin, Germany
^*Correspondence e-mail: franziska.emmerling@bam.de

(Received 27 November 2012; accepted 20 December 2012; online 4 January 2013)

The title compound, {2-[(2-carbamoylethyl)amino]-3-methylpentanoic acid}, C₉H₁₈N₂O₃, is of interest with respect to its biological activity. It was formed during an addition reaction between acrylamide and the amino acid isoleucine. The crystal structure is a three-dimensional network built up by intermolecular N—H⋯O and O—H⋯N hydrogen bonds.

Related literature

For toxicological investigations on acrylamide, see: Besaratinia & Pfeifer (2007 ); Parzefall (2008 ); Bowyer et al. (2009 ); Wang et al. (2010 ); Mei et al. (2010 ); Koyama et al. (2011 ); Lee et al. (2012 ); Nixon et al. (2012 ); Rice (2005 ). For directives on monitoring acrylamide in drinking water, see: EU (2000 ). For the determination of acrylamide in different media, see: Zangrando et al. (2012 ); Marin et al. (2006 ); Lucentini et al. (2009 ); Keramat et al. (2011 ); Tareke et al. (2002 ); Pittet et al. (2004 ); Castle & Eriksson (2005 ); Mizukami et al. (2006 ); Dias Soares et al. (2009 ); Alpmann & Morlock (2008 ); Preston et al. (2009 ); Perez & Osterman-Golkar (2003 ).

Experimental

Crystal data

C₉H₁₈N₂O₃
M_r = 202.25
Orthorhombic, P 2₁ 2₁ 2₁
a = 5.2989 (17) Å
b = 9.024 (3) Å
c = 23.268 (7) Å
V = 1112.6 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 298 K
0.64 × 0.06 × 0.06 mm

Data collection

Bruker APEX CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2008 ) T_min = 0.944, T_max = 0.994
7386 measured reflections
1516 independent reflections
1124 reflections with I > 2σ(I)
R_int = 0.074

Refinement

R[F² > 2σ(F²)] = 0.043
wR(F²) = 0.114
S = 0.95
1516 reflections
127 parameters
H-atom parameters constrained
Δρ_max = 0.42 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O1ⁱ	0.86	2.17	2.982 (3)	159
N1—H1B⋯O1ⁱⁱ	0.86	2.33	3.097 (4)	149
O2—H21⋯N5ⁱⁱⁱ	0.82	1.89	2.708 (2)	176
N5—H51⋯O3^iv	0.98	1.91	2.783 (3)	147
Symmetry codes: (i) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+2]$ ; (ii) x+1, y, z; (iii) x-1, y, z; (iv) $[-x+1, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ .

Data collection: SMART (Bruker, 2001 ); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and ORTEPIII (Burnett & Johnson, 1996 ); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053681205146X/bg2493sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053681205146X/bg2493Isup2.hkl

Supporting information file. DOI: 10.1107/S160053681205146X/bg2493Isup3.mol

Supporting information file. DOI: 10.1107/S160053681205146X/bg2493Isup4.cml

checkCIF report

Comment top

Acrylamide is a water-soluble unsaturated amide, a reactive monomer and an industrial chemical used in many technological applications.

It is also a contaminant in baked and fried starchy food as a result of Maillard reactions involving asparagine and reducing sugars that leads to disseminated human exposure. So people may be exposed to acrylamide in industry as well as in daily life via diet and drinking water. Furthermore, it was recently reported a novel method for the determination of acrylamide in particulare-phase outdoor aerosol (Zangrando et al., 2012).

It is known that acrylamide is a neurotoxin and putative human carcinogen. In the last years a lot of different toxicological investigations have been carried out (Besaratinia and Pfeifer, 2007: Parzefall, 2008; Bowyer et al., 2009;Wang et al., 2010; Mei et al., 2010; Koyama et al., 2011; Lee et al., 2012; Nixon et al., 2012). Therefore, acrylamide was included (with a limit value of 0.1µg/L) to the numerous substances to be monitored in drinking water according to EU Water Framework Directive (EU 2000). The best method for the determination of acrylamide in water is the liquid chromatography/ tandem mass spectrometry (LC—MS/MS) (Marin et al., 2006; Lucentini et al., 2009; Keramat et al., 2011). In the area of foods GC method with bromination of acrylamide as a derivatization reaction was used (Tareke et al., 2002; Pittet et al., 2004; Castle & Eriksson, 2005; Mizukami et al., 2006; Dias Soares et al., 2009). But also methods such as high-performance thin-layer chromatography (HPTLC) (Alpmann & Morlock, 2008) and a bioassay of dietary acrylamide exposure on the basis of monoclonal antibodies (Preston et al., 2009) were used.

In toxicological investigations it could be proven, that reactions between acrylamide and different amino acids take place (Rice, 2005). These reactions and the corresponding adducts can be used also for the analytical determination of acrylamide in drinking water (Perez & Osterman-Golkar, 2003). There the amino acid isoleucine served as a nucleophilic trapping agent. Our group examined the derivatization of acrylamide with isoleucine in the course of the drinking water analysis.

The molecular structure of the reaction product from acrylamide and isoleucine and the atom-labeling scheme is shown in Fig. 1. The absolute configuration has not been determined by anomalous-dispersion effects in diffraction measurements on the crystal, but assigned by reference to an unchanging chiral centre in the synthetic procedure. Each molecule forms six hydrogen bonds to six adjacent molecules leading to a three-dimensional-network structure. In the a-c plane adjacent molecules form strong hydrogen bonds between amino donor groups and oxygen acceptor atoms.Each molecule is further involved in N—H···O bonds parallel the crystallographic b direction. The hydrogen bond network is completed by a further hydrogen bond between a hydroxy donor group and a nitrogen acceptor atom parallel to the a direction. The resulting arrangement together with the hydrogen bonding system (dashed green lines) is shown in Fig. 2.

Related literature top

For toxicological investigations on acrylamide, see: Besaratinia & Pfeifer (2007); Parzefall (2008); Bowyer et al. (2009); Wang et al. (2010); Mei et al. (2010); Koyama et al. (2011); Lee et al. (2012); Nixon et al. (2012); Rice (2005). For directives on monitoring acrylamide in drinking water, see: EU (2000). For the determination of acrylamide in different media, see: Zangrando et al. (2012); Marin et al. (2006); Lucentini et al. (2009); Keramat et al. (2011), Tareke et al. (2002); Pittet et al. (2004); Castle & Eriksson (2005); Mizukami et al. (2006); Dias Soares et al. (2009); Alpmann & Morlock (2008); Preston et al. (2009); Perez & Osterman-Golkar (2003).

Experimental top

The derivatization of acrylamide (for synthesis, > 99%; Merck, Darmstadt, Germany) with L-isoleucine (Biochemica > 99%; Fluka, Deishofen, Germany) was achieved in a water bath at 39 °C. For the reaction 0.4233 g L-isoleucin (3.2 mol) were dissolved in water (19.8 g) and temperated to 30 °C. The pH was set to 10 with sodium hydroxide (2M) and 0.4562 g (6.4 mol) acrylamide was added. The flask was shaken for two minutes and placed in the water bath for 48 h. Crystallized solids were filtered out, washed with cold methanol, redissolved in small amounts of hot water and at 4 °C for one week to yield light yellow crystals with a melting point of 282 °C and a purity (DSC) of 99.9%.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. ORTEP representation of the title compound with atomic labeling shown with 30% probability displacement ellipsoids.
	Fig. 2. View of the unit cell of the title compound along [010]. Hydrogen bonds are drawn as dashed green lines. For clarity, hydrogen atoms not involved in the hydrogen bonding are omitted.

2-[(2-Carbamoylethyl)amino]-3-methylpentanoic acid top

Crystal data top

C₉H₁₈N₂O₃	F(000) = 440
M_r = 202.25	D_x = 1.207 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 1516 reflections
a = 5.2989 (17) Å	θ = 1.8–27.5°
b = 9.024 (3) Å	µ = 0.09 mm⁻¹
c = 23.268 (7) Å	T = 298 K
V = 1112.6 (6) Å³	Needle, colourless
Z = 4	0.64 × 0.06 × 0.06 mm

Data collection top

Bruker APEX CCD area-detector diffractometer	1516 independent reflections
Radiation source: fine-focus sealed tube	1124 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.074
ω/2θ scans	θ_max = 27.5°, θ_min = 1.8°
Absorption correction: multi-scan (SHELXTL [SADABS?]; Sheldrick, 2008)	h = −6→6
T_min = 0.944, T_max = 0.994	k = −10→11
7386 measured reflections	l = −30→25

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)] = 0.043	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.114	H-atom parameters constrained
S = 0.95	w = 1/[σ²(F_o²) + (0.0694P)²] where P = (F_o² + 2F_c²)/3
1516 reflections	(Δ/σ)_max < 0.001
127 parameters	Δρ_max = 0.42 e Å⁻³
0 restraints	Δρ_min = −0.27 e Å⁻³

Crystal data top

C₉H₁₈N₂O₃	V = 1112.6 (6) Å³
M_r = 202.25	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 5.2989 (17) Å	µ = 0.09 mm⁻¹
b = 9.024 (3) Å	T = 298 K
c = 23.268 (7) Å	0.64 × 0.06 × 0.06 mm

Data collection top

Bruker APEX CCD area-detector diffractometer	1516 independent reflections
Absorption correction: multi-scan (SHELXTL [SADABS?]; Sheldrick, 2008)	1124 reflections with I > 2σ(I)
T_min = 0.944, T_max = 0.994	R_int = 0.074
7386 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.043	0 restraints
wR(F²) = 0.114	H-atom parameters constrained
S = 0.95	Δρ_max = 0.42 e Å⁻³
1516 reflections	Δρ_min = −0.27 e Å⁻³
127 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
C10	0.7698 (9)	0.2828 (6)	0.55528 (14)	0.1012 (15)
H102	0.6633	0.2437	0.5256	0.152*
H101	0.9239	0.2271	0.5568	0.152*
H103	0.8073	0.3848	0.5472	0.152*
C9	0.6365 (7)	0.2719 (4)	0.61206 (12)	0.0594 (8)
H9A	0.6549	0.1718	0.6267	0.071*
H9B	0.4579	0.2899	0.6062	0.071*
C11	0.6607 (8)	0.5381 (3)	0.64355 (12)	0.0669 (10)
H11A	0.7246	0.6032	0.6728	0.100*
H11B	0.4800	0.5454	0.6422	0.100*
H11C	0.7297	0.5661	0.6070	0.100*
C8	0.7355 (5)	0.3811 (3)	0.65718 (9)	0.0416 (6)
H8	0.9202	0.3770	0.6555	0.050*
C6	0.6585 (4)	0.3299 (3)	0.71788 (9)	0.0303 (5)
H61	0.7165	0.2210	0.7210	0.036*
C7	0.3729 (4)	0.3374 (3)	0.72786 (10)	0.0325 (5)
O3	0.2475 (3)	0.22453 (18)	0.71760 (8)	0.0472 (5)
O2	0.2878 (3)	0.45814 (17)	0.74539 (7)	0.0461 (5)
H21	0.1361	0.4499	0.7516	0.069*
N5	0.7864 (3)	0.42102 (19)	0.76255 (7)	0.0287 (4)
H51	0.7098	0.5195	0.7647	0.034*
C4	0.7693 (5)	0.3514 (3)	0.82032 (9)	0.0387 (6)
H41	0.8359	0.2514	0.8184	0.046*
H42	0.5935	0.3452	0.8317	0.046*
C3	0.9138 (5)	0.4382 (3)	0.86474 (10)	0.0437 (6)
H31	0.8541	0.5398	0.8653	0.052*
H32	1.0916	0.4392	0.8549	0.052*
C2	0.8789 (5)	0.3691 (3)	0.92360 (11)	0.0441 (6)
O1	0.6669 (4)	0.3386 (3)	0.94118 (8)	0.0640 (7)
N1	1.0852 (5)	0.3443 (3)	0.95370 (10)	0.0571 (7)
H1A	1.0748	0.3050	0.9873	0.069*
H1B	1.2303	0.3674	0.9398	0.069*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C10	0.107 (4)	0.145 (4)	0.051 (2)	0.017 (4)	0.002 (2)	−0.022 (2)
C9	0.0570 (19)	0.073 (2)	0.0485 (16)	0.0103 (17)	−0.0078 (16)	−0.0115 (14)
C11	0.087 (3)	0.0601 (19)	0.0532 (16)	−0.0004 (19)	0.0045 (18)	0.0146 (14)
C8	0.0266 (12)	0.0569 (16)	0.0414 (13)	0.0032 (12)	0.0010 (11)	0.0006 (11)
C6	0.0201 (10)	0.0329 (11)	0.0379 (12)	0.0000 (9)	−0.0006 (9)	−0.0035 (9)
C7	0.0210 (10)	0.0351 (13)	0.0414 (12)	0.0018 (10)	−0.0020 (10)	0.0028 (10)
O3	0.0258 (9)	0.0366 (9)	0.0792 (13)	−0.0046 (8)	−0.0105 (9)	0.0016 (8)
O2	0.0176 (7)	0.0442 (10)	0.0765 (12)	0.0006 (7)	0.0048 (8)	−0.0150 (8)
N5	0.0205 (8)	0.0306 (9)	0.0351 (9)	0.0005 (8)	0.0001 (7)	0.0010 (7)
C4	0.0326 (12)	0.0442 (14)	0.0391 (13)	−0.0061 (12)	−0.0010 (11)	0.0080 (10)
C3	0.0359 (14)	0.0528 (16)	0.0423 (14)	−0.0086 (12)	−0.0040 (11)	0.0059 (12)
C2	0.0343 (13)	0.0568 (17)	0.0412 (13)	−0.0005 (12)	−0.0004 (12)	0.0029 (12)
O1	0.0384 (11)	0.1044 (19)	0.0493 (11)	−0.0072 (12)	0.0022 (9)	0.0191 (11)
N1	0.0412 (13)	0.087 (2)	0.0436 (12)	0.0016 (13)	−0.0024 (11)	0.0155 (12)

Geometric parameters (Å, º) top

C10—C9	1.501 (5)	C7—O3	1.239 (3)
C10—H102	0.9600	C7—O2	1.248 (3)
C10—H101	0.9600	O2—H21	0.8200
C10—H103	0.9600	N5—C4	1.487 (3)
C9—C8	1.532 (4)	N5—H51	0.9781
C9—H9A	0.9700	C4—C3	1.506 (3)
C9—H9B	0.9700	C4—H41	0.9700
C11—C8	1.506 (4)	C4—H42	0.9700
C11—H11A	0.9600	C3—C2	1.516 (3)
C11—H11B	0.9600	C3—H31	0.9700
C11—H11C	0.9600	C3—H32	0.9700
C8—C6	1.541 (3)	C2—O1	1.226 (3)
C8—H8	0.9800	C2—N1	1.318 (3)
C6—N5	1.489 (3)	N1—H1A	0.8600
C6—C7	1.532 (3)	N1—H1B	0.8600
C6—H61	1.0319

C9—C10—H102	109.5	C7—C6—H61	109.0
C9—C10—H101	109.5	C8—C6—H61	105.7
H102—C10—H101	109.5	O3—C7—O2	125.9 (2)
C9—C10—H103	109.5	O3—C7—C6	117.7 (2)
H102—C10—H103	109.5	O2—C7—C6	116.4 (2)
H101—C10—H103	109.5	C7—O2—H21	109.5
C10—C9—C8	113.5 (3)	C4—N5—C6	111.72 (17)
C10—C9—H9A	108.9	C4—N5—H51	108.1
C8—C9—H9A	108.9	C6—N5—H51	110.5
C10—C9—H9B	108.9	N5—C4—C3	111.69 (19)
C8—C9—H9B	108.9	N5—C4—H41	109.3
H9A—C9—H9B	107.7	C3—C4—H41	109.3
C8—C11—H11A	109.5	N5—C4—H42	109.3
C8—C11—H11B	109.5	C3—C4—H42	109.3
H11A—C11—H11B	109.5	H41—C4—H42	107.9
C8—C11—H11C	109.5	C4—C3—C2	110.1 (2)
H11A—C11—H11C	109.5	C4—C3—H31	109.6
H11B—C11—H11C	109.5	C2—C3—H31	109.6
C11—C8—C9	111.8 (2)	C4—C3—H32	109.6
C11—C8—C6	113.9 (2)	C2—C3—H32	109.6
C9—C8—C6	110.2 (2)	H31—C3—H32	108.2
C11—C8—H8	106.9	O1—C2—N1	123.0 (2)
C9—C8—H8	106.9	O1—C2—C3	120.3 (2)
C6—C8—H8	106.9	N1—C2—C3	116.7 (2)
N5—C6—C7	108.63 (18)	C2—N1—H1A	120.0
N5—C6—C8	110.73 (18)	C2—N1—H1B	120.0
C7—C6—C8	112.77 (19)	H1A—N1—H1B	120.0
N5—C6—H61	110.0

C10—C9—C8—C11	71.4 (4)	N5—C6—C7—O2	35.8 (3)
C10—C9—C8—C6	−160.9 (3)	C8—C6—C7—O2	−87.3 (3)
C11—C8—C6—N5	−62.4 (3)	C7—C6—N5—C4	70.3 (2)
C9—C8—C6—N5	171.1 (2)	C8—C6—N5—C4	−165.35 (18)
C11—C8—C6—C7	59.6 (3)	C6—N5—C4—C3	176.1 (2)
C9—C8—C6—C7	−66.9 (3)	N5—C4—C3—C2	176.6 (2)
N5—C6—C7—O3	−144.6 (2)	C4—C3—C2—O1	−49.4 (4)
C8—C6—C7—O3	92.2 (3)	C4—C3—C2—N1	130.4 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1ⁱ	0.86	2.17	2.982 (3)	159
N1—H1B···O1ⁱⁱ	0.86	2.33	3.097 (4)	149
O2—H21···N5ⁱⁱⁱ	0.82	1.89	2.708 (2)	176
N5—H51···O3^iv	0.98	1.91	2.783 (3)	147

Symmetry codes: (i) x+1/2, −y+1/2, −z+2; (ii) x+1, y, z; (iii) x−1, y, z; (iv) −x+1, y+1/2, −z+3/2.

Experimental details

Crystal data
Chemical formula	C₉H₁₈N₂O₃
M_r	202.25
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	298
a, b, c (Å)	5.2989 (17), 9.024 (3), 23.268 (7)
V (Å³)	1112.6 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.64 × 0.06 × 0.06

Data collection
Diffractometer	Bruker APEX CCD area-detector diffractometer
Absorption correction	Multi-scan (SHELXTL [SADABS?]; Sheldrick, 2008)
T_min, T_max	0.944, 0.994
No. of measured, independent and observed [I > 2σ(I)] reflections	7386, 1516, 1124
R_int	0.074
(sin θ/λ)_max (Å⁻¹)	0.651

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.043, 0.114, 0.95
No. of reflections	1516
No. of parameters	127
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.42, −0.27

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008) and ORTEPIII (Burnett & Johnson, 1996), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1ⁱ	0.86	2.17	2.982 (3)	159
N1—H1B···O1ⁱⁱ	0.86	2.33	3.097 (4)	149
O2—H21···N5ⁱⁱⁱ	0.82	1.89	2.708 (2)	176
N5—H51···O3^iv	0.98	1.91	2.783 (3)	147

Symmetry codes: (i) x+1/2, −y+1/2, −z+2; (ii) x+1, y, z; (iii) x−1, y, z; (iv) −x+1, y+1/2, −z+3/2.

References

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Volume 69| Part 2| February 2013| Pages o172-o173

doi:10.1107/S160053681205146X

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