3-{[(Benz­yloxy)carbon­yl]amino}­butanoic acid

Taira Kimino; Isao Fujii

doi:10.1107/S1600536811035276

. 2011 Sep 3;67(Pt 10):o2560. doi: 10.1107/S1600536811035276

3-{[(Benzyloxy)carbonyl]amino}butanoic acid

Taira Kimino ^a, Isao Fujii ^b,^*

PMCID: PMC3201247 PMID: 22058733

Abstract

In the title compound, C₁₂H₁₅NO₄, the butyric acid group has a stretched trans conformation. The dihedral angle between the phenyl ring and the oxycarboxyamino N—(C=O)—O—C plane is 56.6 (2)°. In the crystal, an inversion dimer is formed by a pair of O—H⋯O hydrogen bonds. The dimers are further linked by N—H⋯O hydrogen bonds between amide groups, forming a tape along the b axis.

Related literature

For general background to 3-aminobutanoic acid, see: Cohen et al. (2011 ▶). For bond-length data, see: Allen et al. (1987 ▶). For structures of related metallo-organic compounds, see: Bryan et al. (1961 ▶); Böhm & Seebach (2000 ▶); Gross & Vahrenkamo (2005 ▶).

Experimental

Crystal data

C₁₂H₁₅NO₄
M _r = 237.25
Monoclinic,
a = 23.1413 (7) Å
b = 4.9589 (4) Å
c = 11.0879 (6) Å
β = 103.075 (6)°
V = 1239.41 (13) Å³
Z = 4
Cu Kα radiation
μ = 0.8 mm⁻¹
T = 297 K
0.4 × 0.2 × 0.2 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ▶) T _min = 0.74, T _max = 0.856
2696 measured reflections
2547 independent reflections
1669 reflections with > 2σ(i)
R _int = 0.023
3 standard reflections every 300 reflections intensity decay: none

Refinement

R[F ² > 2σ(F ²)] = 0.046
wR(F ²) = 0.131
S = 1.02
2547 reflections
164 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.14 e Å⁻³
Δρ_min = −0.14 e Å⁻³

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ▶); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: PLATON (Spek, 2009 ▶) and WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811035276/is2769sup1.cif

e-67-o2560-sup1.cif^{(17.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811035276/is2769Isup2.hkl

e-67-o2560-Isup2.hkl^{(122.6KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811035276/is2769Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯O2ⁱ	1.18 (3)	1.48 (3)	2.650 (2)	177 (2)
N1—HN1⋯O3ⁱⁱ	0.85 (2)	2.04 (2)	2.865 (2)	165 (2)

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors would like to thank T. Watadani of Daito Chem and Dr Y. Takahasi for their experimental support.

supplementary crystallographic information

Comment

Solid-phase synthesis is now the accepted method for peptide synthesis, in which the protected natural or non-natural amino acids are widely used. 3-Aminobutanoic acid (BABA) is one of the non-protein amino acids, and it attracts attentions to building block. At the same time, BABA potentially possesses various bioactivities. Downy mildew of lettuce (Bremia lactucae) is a serious disease, but BABA is considered with one of the disease resistance inducers (Cohen et al., 2011). Despite the agrichemical or pharmaceutical desires, crystal structures of BABA derivatives have not been cleared except for the structures of some metallo-organic compounds (Bryan et al., 1961; Gross & Vahrenkamo, 2005; Böhm & Seebach, 2000) because of its difficulty in crystallization.

Fortunately, the title compound, 3-benzyloxycarbonylaminobutanoic acid (Cbz-BABA), (I), was crystallized, and we herein report on the crystal structure. The molecular structure of (I) is shown in Fig. 1. The bond lengths (Allen et al., 1987) and angles are within normal ranges except for the O-H bond length at the carboxy dimer. The part of BABA is essentially similar with that reported by Gross & Vahrenkamo (2005). The butyric acid group owns a stretched trans-conformation (O1-C1-C2-C3-C4). At the β-position the benzyloxycarboxyamino group is attached perpendicular to the butyric acid group. The phenyl group is twisted against the least-squares plane of the oxycarboxyamino group (N1/C5/O3/O4/C6/C7) with the dihedral angle of 56.6 (2)°.

In the crystal structure, an enantiomer makes a planar structure with the intermolecular hydrogen bond (N1—HN1···O3) along the b axis. The planar structure is stacked to the enantiopure layer along the c axis. The carboxy dimer is made from the enantiomeric isomers with the intermolecular hydrogen bond (O1—H1···O2). The H atom is shared by carboxy dimer then the bond distance O1—H1 is longer than that of general carboxy group. The hydrophobic and hydrophilic layers are well separated along the a axis. The structure shows a herring bone stacking mode (Fig. 2).

Experimental

The title compound was purchased from Aldrich-Sigma Co. Ltd. Rod-like colourless crystals suitable for X-ray diffraction were obtained by vapour-phase diffusion of an ethanol and chloroform mixture solution at 297 K.