2-Methyl-aspartic acid monohydrate.

The title compound, C5H9NO4·H2O, is an isomer of the α-amino acid glutamic acid that crystallizes from water in its zwitterionic form as a monohydrate. It is not one of the 20 proteinogenic α-amino acids that are used in living systems and differs from the natural amino acids in that it has an α-methyl group rather than an α-H atom. In the crystal, an O-H⋯O hydrogen bond is present between the acid and water mol-ecules while extensive N-H⋯O and O-H⋯O hydrogen bonds link the components into a three-dimensional array.

Related literature

For the eighty amino acids that have been detected in meteorites or comets, see: Pizzarello et al. (2006 ▶); Glavin & Dworkin, (2009 ▶); Burton et al. (2012 ▶). For the role that crystallization plays in chiral separation, see: Blackmond & Klussmann (2007 ▶); Blackmond et al. (2008 ▶). For the role of the H atom on the α-C atom in enhancing the rate of racemization, see: Yamada et al. (1983 ▶). For the mechanism of racemization of amino acids lacking an α-H atom, see: Pizzarello & Groy (2011 ▶). For the role that crystallization can play in the enrichment of l isovaline and its structure, see: Glavin & Dworkin (2009 ▶); Butcher et al. (2013 ▶). For normal bond lengths and angles, see: Orpen (1993 ▶). For the number of α-methyl amino acids that have been observed with l-enanti­omeric excesses up to 20% that are not believed to be the result of contamination, see: Pizzarello & Cronin (2000 ▶); Glavin & Dworkin (2009 ▶); Glavin et al. (2011 ▶, 2012 ▶); Burton et al. (2013 ▶).

Experimental

Crystal data

C5H9NO4·H2O

M = 165.15

Monoclinic,

a = 9.9690 (6) Å

b = 12.8677 (6) Å

c = 5.8409 (3) Å

β = 106.491 (6)°

V = 718.44 (7) Å3

Z = 4

Cu Kα radiation

μ = 1.20 mm−1

T = 123 K

0.49 × 0.12 × 0.04 mm

Data collection

Agilent Xcalibur Ruby Gemini diffractometer

Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2012 ▶) T min = 0.682, T max = 1.000

5544 measured reflections

1498 independent reflections

1436 reflections with I > 2σ(I)

R int = 0.038

Refinement

R[F 2 > 2σ(F 2)] = 0.090

wR(F 2) = 0.279

S = 1.20

1498 reflections

123 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.50 e Å−3

Δρmin = −0.53 e Å−3

Data collection: CrysAlis PRO (Agilent, 2012 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S1600536813032170/hg5362sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813032170/hg5362Isup2.hkl

Click here for additional data file.

Supplementary material file. DOI: 10.1107/S1600536813032170/hg5362Isup3.cml

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

C5H9NO4·H2O	F(000) = 352
Mr = 165.15	Dx = 1.527 Mg m−3
Monoclinic, P21/c	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: -P 2ybc	Cell parameters from 3596 reflections
a = 9.9690 (6) Å	θ = 3.4–77.1°
b = 12.8677 (6) Å	µ = 1.20 mm−1
c = 5.8409 (3) Å	T = 123 K
β = 106.491 (6)°	Plate, colourless
V = 718.44 (7) Å3	0.49 × 0.12 × 0.04 mm
Z = 4

Agilent Xcalibur Ruby Gemini diffractometer	1498 independent reflections
Radiation source: Enhance (Cu) X-ray Source	1436 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.038
Detector resolution: 10.5081 pixels mm-1	θmax = 77.3°, θmin = 3.4°
ω scans	h = −12→12
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2012)	k = −15→16
Tmin = 0.682, Tmax = 1.000	l = −7→5
5544 measured reflections

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)] = 0.090	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.279	H atoms treated by a mixture of independent and constrained refinement
S = 1.20	w = 1/[σ2(Fo2) + (0.171P)2 + 1.5626P] where P = (Fo2 + 2Fc2)/3
1498 reflections	(Δ/σ)max < 0.001
123 parameters	Δρmax = 0.50 e Å−3
0 restraints	Δρmin = −0.53 e Å−3

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.

	x	y	z	Uiso*/Ueq
O1	0.1948 (3)	0.4358 (2)	0.7672 (5)	0.0230 (7)
O2	0.3545 (3)	0.3270 (2)	0.6994 (5)	0.0214 (6)
O3	0.3796 (3)	0.5820 (2)	0.5612 (5)	0.0212 (6)
O4	0.2105 (3)	0.6995 (2)	0.4131 (6)	0.0236 (7)
H4O	0.276 (7)	0.743 (6)	0.457 (13)	0.042 (17)*
O1W	0.3772 (3)	0.8584 (2)	0.5403 (6)	0.0246 (7)
H1W1	0.469 (7)	0.851 (5)	0.608 (12)	0.033 (15)*
H1W2	0.380 (6)	0.879 (4)	0.409 (11)	0.018 (12)*
N1	0.3151 (3)	0.3888 (3)	0.2516 (6)	0.0183 (7)
H1A	0.294 (6)	0.405 (5)	0.095 (11)	0.027*
H1B	0.332 (6)	0.320 (5)	0.249 (10)	0.027*
H1C	0.393 (6)	0.422 (5)	0.325 (11)	0.027*
C1	0.2565 (4)	0.3913 (3)	0.6364 (7)	0.0182 (8)
C2	0.2010 (4)	0.4134 (3)	0.3646 (7)	0.0174 (8)
C3	0.0787 (4)	0.3399 (3)	0.2591 (7)	0.0198 (8)
H3A	0.0458	0.3495	0.0857	0.030*
H3B	0.0023	0.3552	0.3289	0.030*
H3C	0.1095	0.2679	0.2950	0.030*
C4	0.1559 (4)	0.5261 (3)	0.3097 (7)	0.0188 (8)
H4A	0.1373	0.5379	0.1360	0.023*
H4B	0.0671	0.5374	0.3502	0.023*
C5	0.2607 (4)	0.6045 (3)	0.4406 (7)	0.0183 (8)

	U11	U22	U33	U12	U13	U23
O1	0.0262 (14)	0.0207 (14)	0.0234 (14)	0.0023 (11)	0.0091 (11)	0.0003 (11)
O2	0.0223 (13)	0.0144 (13)	0.0254 (13)	0.0015 (10)	0.0033 (11)	0.0024 (10)
O3	0.0178 (12)	0.0163 (12)	0.0275 (14)	0.0010 (10)	0.0032 (11)	0.0008 (11)
O4	0.0228 (13)	0.0124 (12)	0.0333 (15)	0.0024 (11)	0.0041 (12)	−0.0012 (11)
O1W	0.0222 (14)	0.0216 (14)	0.0288 (16)	−0.0019 (11)	0.0050 (12)	0.0042 (11)
N1	0.0189 (16)	0.0142 (15)	0.0225 (16)	−0.0011 (12)	0.0070 (12)	−0.0011 (12)
C1	0.0180 (17)	0.0103 (16)	0.0262 (19)	−0.0053 (12)	0.0063 (15)	−0.0004 (13)
C2	0.0167 (17)	0.0118 (15)	0.0242 (18)	0.0009 (13)	0.0065 (14)	−0.0002 (13)
C3	0.0200 (17)	0.0149 (16)	0.0232 (18)	−0.0032 (14)	0.0038 (14)	−0.0029 (14)
C4	0.0193 (17)	0.0141 (17)	0.0215 (16)	0.0034 (13)	0.0034 (14)	0.0005 (14)
C5	0.0212 (17)	0.0106 (16)	0.0244 (18)	0.0014 (13)	0.0087 (14)	−0.0005 (13)

O1—C1	1.247 (5)	N1—H1C	0.88 (6)
O2—C1	1.253 (5)	C1—C2	1.552 (5)
O3—C5	1.229 (5)	C2—C4	1.525 (5)
O4—C5	1.313 (4)	C2—C3	1.528 (5)
O4—H4O	0.84 (8)	C3—H3A	0.9800
O1W—H1W1	0.89 (6)	C3—H3B	0.9800
O1W—H1W2	0.82 (6)	C3—H3C	0.9800
N1—C2	1.502 (5)	C4—C5	1.497 (5)
N1—H1A	0.91 (6)	C4—H4A	0.9900
N1—H1B	0.90 (7)	C4—H4B	0.9900
C5—O4—H4O	110 (5)	C3—C2—C1	108.1 (3)
H1W1—O1W—H1W2	99 (6)	C2—C3—H3A	109.5
C2—N1—H1A	114 (4)	C2—C3—H3B	109.5
C2—N1—H1B	112 (4)	H3A—C3—H3B	109.5
H1A—N1—H1B	102 (5)	C2—C3—H3C	109.5
C2—N1—H1C	111 (4)	H3A—C3—H3C	109.5
H1A—N1—H1C	108 (5)	H3B—C3—H3C	109.5
H1B—N1—H1C	110 (5)	C5—C4—C2	114.3 (3)
O1—C1—O2	127.0 (4)	C5—C4—H4A	108.7
O1—C1—C2	116.6 (3)	C2—C4—H4A	108.7
O2—C1—C2	116.3 (3)	C5—C4—H4B	108.7
N1—C2—C4	108.8 (3)	C2—C4—H4B	108.7
N1—C2—C3	108.0 (3)	H4A—C4—H4B	107.6
C4—C2—C3	110.5 (3)	O3—C5—O4	124.2 (3)
N1—C2—C1	108.5 (3)	O3—C5—C4	123.6 (3)
C4—C2—C1	112.8 (3)	O4—C5—C4	112.2 (3)
O1—C1—C2—N1	158.8 (3)	N1—C2—C4—C5	−71.6 (4)
O2—C1—C2—N1	−24.4 (4)	C3—C2—C4—C5	170.0 (3)
O1—C1—C2—C4	38.2 (4)	C1—C2—C4—C5	48.8 (4)
O2—C1—C2—C4	−145.0 (3)	C2—C4—C5—O3	8.0 (6)
O1—C1—C2—C3	−84.3 (4)	C2—C4—C5—O4	−171.5 (3)
O2—C1—C2—C3	92.6 (4)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4O···O1W	0.84 (8)	1.78 (8)	2.607 (4)	165 (7)
O1W—H1W1···O2i	0.89 (6)	1.83 (6)	2.705 (4)	168 (6)
O1W—H1W2···O3ii	0.82 (6)	2.09 (6)	2.909 (4)	174 (5)
N1—H1A···O1iii	0.91 (6)	1.93 (6)	2.807 (5)	164 (5)
N1—H1B···O2iv	0.90 (7)	1.94 (7)	2.832 (4)	172 (5)
N1—H1C···O3v	0.88 (6)	2.18 (6)	2.951 (4)	146 (5)
N1—H1C···O3	0.88 (6)	2.50 (6)	3.033 (4)	119 (5)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H4O⋯O1W	0.84 (8)	1.78 (8)	2.607 (4)	165 (7)
O1W—H1W1⋯O2i	0.89 (6)	1.83 (6)	2.705 (4)	168 (6)
O1W—H1W2⋯O3ii	0.82 (6)	2.09 (6)	2.909 (4)	174 (5)
N1—H1A⋯O1iii	0.91 (6)	1.93 (6)	2.807 (5)	164 (5)
N1—H1B⋯O2iv	0.90 (7)	1.94 (7)	2.832 (4)	172 (5)
N1—H1C⋯O3v	0.88 (6)	2.18 (6)	2.951 (4)	146 (5)
N1—H1C⋯O3	0.88 (6)	2.50 (6)	3.033 (4)	119 (5)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) .