(Z)-4-(tert-Butyl­amino)-4-oxo-2-butenoic acid

The title compound, C₈H₁₃NO₃, is an amidated maleic acid derivative. There are intramolecular O—H...O and intermolecular step-like N—H...O hydrogen bonds, forming zigzag chains along the c axis.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.042
• wR factor = 0.134
• Data-to-parameter ratio = 19.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low ....         45 Perc.
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       1.02
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....         C5

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

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

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Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1991); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 2000); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: TEXSAN and Mercury (Bruno et al., 2002); software used to prepare material for publication: TEXSAN and Mercury.

(I)

Crystal data

C8H13NO3	F(000) = 368
Mr = 171.19	Dx = 1.191 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 9.283 (4) Å	θ = 14.3–15.0°
b = 8.416 (3) Å	µ = 0.09 mm^−1
c = 12.680 (5) Å	T = 296 K
β = 105.42 (3)°	Prismatic, colorless
V = 955.0 (7) Å^3	0.50 × 0.20 × 0.20 mm
Z = 4

Data collection

Rigaku AFC5R diffractometer	994 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.037
Graphite monochromator	θmax = 27.5°, θmin = 2.9°
ω–2θ scans	h = 0→12
Absorption correction: ψ scan (North et al., 1968)	k = 0→10
Tmin = 0.900, Tmax = 0.962	l = −16→15
2325 measured reflections	3 standard reflections every 150 reflections
2195 independent reflections	intensity decay: 0.4%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.134	H atoms treated by a mixture of independent and constrained refinement
S = 0.98	w = 1/[σ^2(Fo^2) + (0.057P)^2 + 0.0332P] where P = (Fo^2 + 2Fc^2)/3
2195 reflections	(Δ/σ)max < 0.001
112 parameters	Δρmax = 0.14 e Å^−3
0 restraints	Δρmin = −0.19 e Å^−3

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	0.26132 (17)	0.03658 (18)	0.22821 (11)	0.0540 (4)
O2	0.3781 (2)	−0.4179 (2)	0.12000 (13)	0.0689 (5)
O3	0.3148 (2)	−0.1660 (2)	0.10417 (12)	0.0650 (5)
H2	0.295 (3)	−0.077 (3)	0.151 (2)	0.078*
N1	0.2532 (2)	0.05087 (19)	0.40424 (13)	0.0441 (5)
H1	0.2777	0.0037	0.4666	0.053*
C1	0.3613 (2)	−0.2925 (3)	0.16292 (18)	0.0479 (5)
C2	0.3967 (2)	−0.2847 (2)	0.28363 (17)	0.0441 (5)
H3	0.4495	−0.3720	0.3191	0.053*
C3	0.3668 (2)	−0.1756 (2)	0.35054 (16)	0.0439 (5)
H4	0.3978	−0.1997	0.4247	0.053*
C4	0.2904 (2)	−0.0200 (2)	0.32250 (15)	0.0417 (5)
C5	0.1728 (3)	0.2047 (3)	0.39841 (17)	0.0482 (5)
C6	0.0242 (3)	0.1962 (3)	0.3109 (2)	0.0716 (8)
H5	0.0424	0.1794	0.2407	0.086*
H6	−0.0292	0.2941	0.3100	0.086*
H7	−0.0341	0.1099	0.3270	0.086*
C7	0.2688 (3)	0.3382 (3)	0.3742 (3)	0.0741 (8)
H8	0.2855	0.3218	0.3035	0.089*
H9	0.3629	0.3395	0.4288	0.089*
H10	0.2187	0.4378	0.3749	0.089*
C8	0.1447 (4)	0.2285 (3)	0.5103 (2)	0.0772 (9)
H11	0.0845	0.1428	0.5249	0.093*
H12	0.0935	0.3274	0.5112	0.093*
H13	0.2385	0.2304	0.5653	0.093*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0732 (11)	0.0492 (9)	0.0398 (8)	0.0125 (8)	0.0154 (7)	0.0095 (7)
O2	0.0837 (13)	0.0648 (11)	0.0535 (10)	0.0097 (10)	0.0101 (9)	−0.0200 (8)
O3	0.0910 (14)	0.0671 (11)	0.0407 (8)	0.0185 (10)	0.0245 (9)	0.0045 (8)
N1	0.0537 (11)	0.0395 (10)	0.0372 (9)	0.0057 (9)	0.0088 (8)	0.0034 (8)
C1	0.0432 (13)	0.0554 (14)	0.0445 (12)	−0.0014 (12)	0.0109 (10)	−0.0061 (11)
C2	0.0473 (13)	0.0399 (11)	0.0432 (11)	0.0034 (10)	0.0089 (10)	−0.0001 (10)
C3	0.0516 (13)	0.0422 (11)	0.0344 (10)	0.0018 (10)	0.0050 (9)	0.0033 (9)
C4	0.0469 (13)	0.0392 (11)	0.0380 (10)	−0.0027 (10)	0.0097 (9)	−0.0003 (10)
C5	0.0527 (14)	0.0428 (12)	0.0478 (12)	0.0069 (11)	0.0113 (10)	−0.0008 (10)
C6	0.0573 (16)	0.0741 (18)	0.0774 (17)	0.0151 (15)	0.0077 (13)	−0.0069 (15)
C7	0.0736 (18)	0.0433 (14)	0.103 (2)	0.0041 (13)	0.0201 (16)	0.0027 (14)
C8	0.100 (2)	0.0702 (17)	0.0649 (17)	0.0205 (17)	0.0280 (16)	−0.0094 (14)

Geometric parameters (Å, º)

O1—C4	1.248 (2)	C5—C7	1.515 (3)
O2—C1	1.216 (3)	C5—C8	1.522 (3)
O3—C1	1.305 (3)	C5—C6	1.524 (3)
O3—H2	1.01 (3)	C6—H5	0.9600
N1—C4	1.319 (2)	C6—H6	0.9600
N1—C5	1.486 (3)	C6—H7	0.9600
N1—H1	0.8600	C7—H8	0.9600
C1—C2	1.479 (3)	C7—H9	0.9600
C2—C3	1.329 (3)	C7—H10	0.9600
C2—H3	0.9300	C8—H11	0.9600
C3—C4	1.486 (3)	C8—H12	0.9600
C3—H4	0.9300	C8—H13	0.9600
C4—O1—H2	111.3 (10)	C7—C5—C6	110.7 (2)
C1—O3—H2	110.9 (14)	C8—C5—C6	109.8 (2)
C4—N1—C5	126.00 (17)	C5—C6—H5	109.5
C4—N1—H1	117.0	C5—C6—H6	109.5
C5—N1—H1	117.0	H5—C6—H6	109.5
O2—C1—O3	121.0 (2)	C5—C6—H7	109.5
O2—C1—C2	118.8 (2)	H5—C6—H7	109.5
O3—C1—C2	120.2 (2)	H6—C6—H7	109.5
C3—C2—C1	131.6 (2)	C5—C7—H8	109.5
C3—C2—H3	114.2	C5—C7—H9	109.5
C1—C2—H3	114.2	H8—C7—H9	109.5
C2—C3—C4	128.58 (19)	C5—C7—H10	109.5
C2—C3—H4	115.7	H8—C7—H10	109.5
C4—C3—H4	115.7	H9—C7—H10	109.5
O1—C4—N1	123.03 (19)	C5—C8—H11	109.5
O1—C4—C3	122.21 (18)	C5—C8—H12	109.5
N1—C4—C3	114.74 (17)	H11—C8—H12	109.5
N1—C5—C7	109.96 (18)	C5—C8—H13	109.5
N1—C5—C8	106.05 (18)	H11—C8—H13	109.5
C7—C5—C8	110.3 (2)	H12—C8—H13	109.5
N1—C5—C6	109.91 (18)
O2—C1—C2—C3	−167.3 (2)	C2—C3—C4—O1	−9.9 (4)
O3—C1—C2—C3	13.6 (4)	C2—C3—C4—N1	168.7 (2)
C1—C2—C3—C4	−2.5 (4)	C4—N1—C5—C7	−65.5 (3)
C5—N1—C4—O1	0.1 (3)	C4—N1—C5—C8	175.3 (2)
C5—N1—C4—C3	−178.40 (18)	C4—N1—C5—C6	56.7 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2^i	0.86	2.05	2.897 (3)	168
O3—H2···O1	1.01 (3)	1.46 (3)	2.458 (2)	172 (2)

Symmetry code: (i) x, −y−1/2, z+1/2.