2-Aza­niumyl-4-(ethyl­carbamo­yl)butano­ate: the zwitterionic form of the amino acid theanine

Kang, S.-K.; Chen, Y.-H.; Qian, S.-S.; Hu, H.

doi:10.1107/S1600536810050701

Volume 67
Part 1
Page o82
January 2011

Received 2 November 2010
Accepted 3 December 2010
Online 11 December 2010

Key indicators
Single-crystal X-ray study
T = 273 K
Mean (C-C) = 0.003 Å
Disorder in main residue
R = 0.051
wR = 0.147
Data-to-parameter ratio = 15.0
Details

2-Azaniumyl-4-(ethylcarbamoyl)butanoate: the zwitterionic form of the amino acid theanine

Shou-Kai Kang,^a Yue-Hu Chen,^a Shao-Song Qian ^a and Hao Hu ^a ^*

^aSchool of Life Science, ShanDong University of Technology, ZiBo 255049, People's Republic of China
Correspondence e-mail: huhao@sdut.edu.cn

In the title zwitterion, C₇H₁₄N₂O₃, the ethylamino and the 5-oxo groups are positionally disordered with occupancy ratios of 0.50:0.50 and 0.70:0.30, respectively. The terminal ethyl -CH₃ group undergoes considerable thermal motion. In the crystal, molecules are linked via N-HO hydrogen bonds, forming a two-dimensional arrangement propagating in the bc plane.

Related literature

For details of the physiological activity of the amino acid theanine, commonly found in certain teas, see: Li et al. (2006).

Experimental

Crystal data

C₇H₁₄N₂O₃
M_r = 174.20
Monoclinic, P 2₁ /c
a = 19.606 (6) Å
b = 4.7904 (15) Å
c = 9.812 (3) Å
= 90.501 (6)°
V = 921.5 (5) Å³
Z = 4
Mo K radiation
= 0.10 mm^-1
T = 273 K
0.15 × 0.12 × 0.06 mm

Data collection

Bruker SMART CCD area-detector diffractometer
5580 measured reflections
2218 independent reflections
1276 reflections with I > 2(I)
R_int = 0.039

Refinement

R[F² > 2(F²)] = 0.051
wR(F²) = 0.147
S = 1.01
2218 reflections
148 parameters
26 restraints
H-atom parameters constrained
_max = 0.23 e Å^-3
_min = -0.20 e Å^-3

Table 1
Hydrogen-bond geometry (Å, °)

D-HA	D-H	HA	DA	D-HA
N1-H1AO2ⁱ	0.89	1.89	2.776 (2)	174
N1-H1BO1ⁱⁱ	0.89	1.96	2.8332 (19)	165
N1-H1CO1ⁱⁱⁱ	0.89	1.97	2.850 (2)	171
N2-H2O3^iv	0.86	2.16	2.93 (2)	149
N2'-H2'O3'^iv	0.86	2.01	2.85 (3)	166
Symmetry codes: (i) $[-x, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (ii) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (iii) $[x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]$ ; (iv) x, y-1, z.

Data collection: SMART (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SU2225 ).

Acknowledgements

This project was sponsored by the Doctoral Research Foundation of ShanDong University of Technology, People's Republic of China.

References

Bruker (2007). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
Li, J., Li, P. & Liu, F. (2006). LWT Food Sci. Technol. 41, 883-889.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Spek, A. L. (2009). Acta Cryst. D65, 148-155.

organic compounds