N-Acetyl-L-valine

The title compound, C₇H₁₃NO₃, was prepared by acetyl­ation of L-valine. The C(carbonyl)-N bond length is 1.324 (2) Å, which corresponds to the C-N bond length of a typical acyl­amine group.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.034
• wR factor = 0.072
• Data-to-parameter ratio = 10.9

checkCIF/PLATON results

No syntax errors found



Alert level C
STRVA01_ALERT_2_C           Chirality of atom sites is inverted?
           From the CIF: _refine_ls_abs_structure_Flack   10.000
           From the CIF: _refine_ls_abs_structure_Flack_su   10.000
PLAT032_ALERT_4_C Std Uncertainty in Flack Parameter too High ....      10.00
PLAT033_ALERT_2_C Flack Parameter Value Deviates from Zero .......      10.00

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.48
           From the CIF: _reflns_number_total               1099
           Count of symmetry unique reflns         1120
           Completeness (_total/calc)             98.12%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present           no

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

(I)

Crystal data

C7H13NO3	Dx = 1.276 Mg m^−3
Mr = 159.18	Melting point = 437–438 K
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 7521 reflections
a = 6.654 (1) Å	θ = 3.1–27.5°
b = 9.444 (2) Å	µ = 0.10 mm^−1
c = 13.182 (3) Å	T = 293 K
V = 828.4 (3) Å^3	Prism, colorless
Z = 4	0.20 × 0.20 × 0.18 mm
F(000) = 344

Data collection

Rigaku R-AXIS RAPID diffractometer	830 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.021
Graphite monochromator	θmax = 27.5°, θmin = 2.7°
ω/2θ scans	h = −8→8
1841 measured reflections	k = −11→12
1099 independent reflections	l = −16→17

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.034	w = 1/[σ^2(Fo^2) + (0.034P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.072	(Δ/σ)max < 0.001
S = 0.91	Δρmax = 0.12 e Å^−3
1099 reflections	Δρmin = −0.13 e Å^−3
101 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.052 (4)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983)
Secondary atom site location: difference Fourier map	Absolute structure parameter: 10 (10)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.89825 (19)	0.73896 (12)	0.78888 (12)	0.0387 (4)
N1	0.8761 (2)	0.51588 (14)	0.72868 (12)	0.0319 (4)
H1	0.9308	0.4334	0.7279	0.038*
O3	0.3855 (2)	0.42029 (16)	0.63941 (12)	0.0506 (5)
H3	0.3124	0.3540	0.6553	0.076*
O2	0.5808 (2)	0.33061 (16)	0.75927 (13)	0.0539 (5)
C3	0.9624 (3)	0.61527 (18)	0.78453 (16)	0.0300 (4)
C5	0.7383 (3)	0.5484 (2)	0.55498 (17)	0.0368 (5)
H5	0.6098	0.5652	0.5206	0.044*
C2	1.1434 (3)	0.5709 (2)	0.84340 (17)	0.0411 (5)
H2A	1.1719	0.4731	0.8300	0.062*
H2B	1.1184	0.5835	0.9146	0.062*
H2C	1.2564	0.6278	0.8235	0.062*
C4	0.5508 (3)	0.4174 (2)	0.69554 (17)	0.0342 (5)
C1	0.6955 (3)	0.53645 (19)	0.66871 (17)	0.0319 (5)
H1A	0.6338	0.6256	0.6905	0.038*
C6	0.8279 (4)	0.4150 (2)	0.51105 (18)	0.0513 (6)
H6A	0.7393	0.3367	0.5238	0.077*
H6B	0.9558	0.3970	0.5422	0.077*
H6C	0.8455	0.4263	0.4392	0.077*
C7	0.8729 (4)	0.6763 (2)	0.5345 (2)	0.0616 (8)
H7A	0.8117	0.7598	0.5623	0.092*
H7B	0.8900	0.6878	0.4626	0.092*
H7C	1.0016	0.6616	0.5657	0.092*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0341 (7)	0.0257 (6)	0.0563 (10)	0.0029 (6)	−0.0015 (8)	−0.0058 (7)
N1	0.0308 (7)	0.0223 (7)	0.0425 (10)	0.0022 (6)	−0.0026 (8)	−0.0027 (7)
O3	0.0355 (8)	0.0545 (9)	0.0619 (11)	−0.0149 (7)	−0.0069 (8)	0.0073 (9)
O2	0.0451 (9)	0.0515 (8)	0.0650 (11)	−0.0128 (7)	−0.0040 (10)	0.0197 (10)
C3	0.0282 (8)	0.0287 (9)	0.0332 (11)	−0.0017 (8)	0.0047 (9)	0.0009 (9)
C5	0.0365 (10)	0.0332 (10)	0.0406 (13)	−0.0016 (9)	−0.0073 (10)	0.0025 (10)
C2	0.0378 (11)	0.0373 (10)	0.0481 (13)	−0.0011 (9)	−0.0053 (10)	−0.0008 (11)
C4	0.0290 (9)	0.0334 (9)	0.0401 (12)	−0.0011 (8)	0.0032 (9)	−0.0055 (10)
C1	0.0289 (9)	0.0226 (9)	0.0443 (12)	0.0010 (7)	−0.0034 (9)	−0.0026 (9)
C6	0.0587 (13)	0.0570 (14)	0.0383 (13)	0.0091 (11)	−0.0012 (12)	−0.0044 (13)
C7	0.0736 (18)	0.0584 (14)	0.0529 (15)	−0.0260 (14)	−0.0022 (15)	0.0142 (14)

Geometric parameters (Å, º)

O1—C3	1.245 (2)	C2—H2A	0.9600
N1—C3	1.324 (2)	C2—H2B	0.9600
N1—C1	1.452 (2)	C2—H2C	0.9600
N1—H1	0.8600	C4—C1	1.522 (3)
O3—C4	1.326 (2)	C1—H1A	0.9800
O3—H3	0.8200	C6—H6A	0.9600
O2—C4	1.191 (2)	C6—H6B	0.9600
C3—C2	1.493 (3)	C6—H6C	0.9600
C5—C6	1.510 (3)	C7—H7A	0.9600
C5—C7	1.528 (3)	C7—H7B	0.9600
C5—C1	1.530 (3)	C7—H7C	0.9600
C5—H5	0.9800
C3—N1—C1	124.54 (14)	O2—C4—C1	124.49 (18)
C3—N1—H1	117.7	O3—C4—C1	112.33 (17)
C1—N1—H1	117.7	N1—C1—C4	107.37 (15)
C4—O3—H3	109.5	N1—C1—C5	112.91 (15)
O1—C3—N1	122.83 (17)	C4—C1—C5	113.57 (17)
O1—C3—C2	121.05 (17)	N1—C1—H1A	107.6
N1—C3—C2	116.12 (16)	C4—C1—H1A	107.6
C6—C5—C7	111.13 (18)	C5—C1—H1A	107.6
C6—C5—C1	112.81 (17)	C5—C6—H6A	109.5
C7—C5—C1	109.92 (18)	C5—C6—H6B	109.5
C6—C5—H5	107.6	H6A—C6—H6B	109.5
C7—C5—H5	107.6	C5—C6—H6C	109.5
C1—C5—H5	107.6	H6A—C6—H6C	109.5
C3—C2—H2A	109.5	H6B—C6—H6C	109.5
C3—C2—H2B	109.5	C5—C7—H7A	109.5
H2A—C2—H2B	109.5	C5—C7—H7B	109.5
C3—C2—H2C	109.5	H7A—C7—H7B	109.5
H2A—C2—H2C	109.5	C5—C7—H7C	109.5
H2B—C2—H2C	109.5	H7A—C7—H7C	109.5
O2—C4—O3	123.18 (19)	H7B—C7—H7C	109.5
C1—N1—C3—O1	−1.9 (3)	O2—C4—C1—C5	129.9 (2)
C1—N1—C3—C2	177.95 (17)	O3—C4—C1—C5	−49.9 (2)
C3—N1—C1—C4	−129.47 (18)	C6—C5—C1—N1	63.3 (2)
C3—N1—C1—C5	104.6 (2)	C7—C5—C1—N1	−61.3 (2)
O2—C4—C1—N1	4.3 (3)	C6—C5—C1—C4	−59.2 (2)
O3—C4—C1—N1	−175.47 (15)	C7—C5—C1—C4	176.17 (16)