Unusual crystal structure of N-substituted maleamic acid – very strong effect of intramolecular hydrogen bonds

N-Carbamylmaleamic acid (malur) undergoes cyclodehydration under favourable conditions, as expected, to give N-carbamyl maleimide. N-(Carboxymethyl) maleamic acid (malgly), however, does not undergo a similar cyclization reaction. Strong π bonding between the C and N of the amide group as well as two intramolecular hydrogen bonds makes malgly a planar molecule, as revealed by single-crystal X-ray studies.

S1. Experimental

S1.1. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1.

S2. Results and discussion

Computing details

Data collection: Bruker SMART for tpr375; CrysAlis PRO, Agilent Technologies, Version 1.171.36.28 (release 01-02-2013 CrysAlis171 .NET) (compiled Feb 1 2013,16:14:44) for emku145. Cell refinement: Bruker SMART for tpr375; CrysAlis PRO, Agilent Technologies, Version 1.171.36.28 (release 01-02-2013 CrysAlis171 .NET) (compiled Feb 1 2013,16:14:44) for emku145. Data reduction: Bruker SAINT for tpr375; CrysAlis PRO, Agilent Technologies, Version 1.171.36.28 (release 01-02-2013 CrysAlis171 .NET) (compiled Feb 1 2013,16:14:44) for emku145. For both compounds, program(s) used to solve structure: SHELXL97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008).

Figures

(tpr375)

Crystal data

C12H14N2O10	Z = 2
Mr = 346.25	F(000) = 360
Triclinic, P1	Dx = 1.611 Mg m^−3
a = 8.1895 (7) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.8902 (9) Å	Cell parameters from 5586 reflections
c = 10.6709 (9) Å	θ = 0.00–0.00°
α = 113.376 (1)°	µ = 0.14 mm^−1
β = 104.250 (1)°	T = 273 K
γ = 103.472 (1)°	0.42 × 0.40 × 0.26 mm
V = 713.87 (11) Å^3

Data collection

CCD area detector diffractometer	2770 independent reflections
Radiation source: fine-focus sealed tube	2485 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
phi and ω scans	θmax = 26.0°, θmin = 2.3°
Absorption correction: multi-scan SADABS	h = −10→10
Tmin = 0.942, Tmax = 0.964	k = −12→12
7343 measured reflections	l = −13→13

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.036	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.103	w = 1/[σ^2(Fo^2) + (0.0624P)^2 + 0.111P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max = 0.001
2770 reflections	Δρmax = 0.19 e Å^−3
236 parameters	Δρmin = −0.22 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.022 (4)

Special details

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
C1	0.30523 (16)	0.38307 (15)	0.27100 (14)	0.0359 (3)
C2	0.38612 (16)	0.54886 (15)	0.30038 (14)	0.0369 (3)
H2A	0.3018	0.5906	0.2725	0.044*
C3	0.55791 (17)	0.64788 (15)	0.35951 (14)	0.0365 (3)
H3	0.5756	0.7478	0.3677	0.044*
C4	0.72464 (16)	0.62028 (14)	0.41404 (13)	0.0337 (3)
C5	1.05012 (16)	0.72501 (15)	0.52427 (16)	0.0404 (3)
H5A	1.0584	0.6343	0.4487	0.048*
H5B	1.0553	0.7071	0.6080	0.048*
C6	1.20698 (16)	0.87195 (15)	0.57111 (14)	0.0353 (3)
C7	−0.19123 (16)	0.15212 (15)	0.75852 (14)	0.0371 (3)
C8	−0.11311 (17)	0.04642 (14)	0.79785 (14)	0.0379 (3)
H8	−0.1988	−0.0474	0.7779	0.046*
C9	0.05829 (17)	0.06284 (15)	0.85670 (14)	0.0381 (3)
H9	0.0742	−0.0204	0.8717	0.046*
C10	0.22671 (16)	0.19506 (14)	0.90154 (13)	0.0348 (3)
C11	0.55194 (16)	0.30275 (15)	1.00200 (15)	0.0387 (3)
H11A	0.5565	0.4022	1.0757	0.046*
H11B	0.5619	0.3158	0.9184	0.046*
C12	0.70842 (16)	0.26459 (15)	1.06553 (14)	0.0368 (3)
H1X	0.883 (2)	0.823 (2)	0.4682 (18)	0.055 (5)*
H3X	1.460 (3)	0.953 (2)	0.6475 (19)	0.071 (5)*
H10X	0.960 (3)	0.350 (2)	1.153 (2)	0.077 (6)*
H2Y	0.382 (2)	0.100 (2)	0.9632 (18)	0.063 (5)*
N1	0.87948 (14)	0.73978 (13)	0.46740 (12)	0.0367 (3)
N2	0.38042 (14)	0.17905 (13)	0.95489 (12)	0.0376 (3)
O1	0.14090 (12)	0.31373 (12)	0.21363 (12)	0.0521 (3)
O2	0.40728 (12)	0.31060 (11)	0.30544 (12)	0.0478 (3)
H2X	0.5142	0.3697	0.3421	0.072*
O3	0.72413 (12)	0.49293 (11)	0.41169 (12)	0.0456 (3)
O4	1.19149 (12)	0.98929 (11)	0.56895 (11)	0.0464 (3)
O5	1.36132 (12)	0.85533 (12)	0.61524 (13)	0.0525 (3)
O6	−0.35560 (12)	0.11275 (12)	0.70682 (12)	0.0516 (3)
O7	−0.08702 (12)	0.28594 (11)	0.77821 (13)	0.0496 (3)
H7X	0.0193	0.3011	0.8194	0.074*
O8	0.22971 (12)	0.31704 (11)	0.89144 (12)	0.0481 (3)
O9	0.69398 (13)	0.14374 (12)	1.07034 (13)	0.0554 (3)
O10	0.86250 (13)	0.38047 (12)	1.11300 (13)	0.0561 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0241 (6)	0.0358 (6)	0.0467 (6)	0.0086 (5)	0.0074 (5)	0.0237 (5)
C2	0.0258 (6)	0.0359 (6)	0.0536 (7)	0.0134 (5)	0.0103 (5)	0.0274 (6)
C3	0.0295 (6)	0.0300 (6)	0.0526 (7)	0.0113 (5)	0.0115 (5)	0.0246 (5)
C4	0.0249 (6)	0.0305 (6)	0.0438 (6)	0.0075 (5)	0.0086 (5)	0.0205 (5)
C5	0.0231 (6)	0.0364 (7)	0.0628 (8)	0.0084 (5)	0.0086 (5)	0.0309 (6)
C6	0.0254 (6)	0.0332 (6)	0.0473 (7)	0.0095 (5)	0.0098 (5)	0.0224 (5)
C7	0.0251 (6)	0.0335 (6)	0.0506 (7)	0.0093 (5)	0.0097 (5)	0.0220 (5)
C8	0.0280 (6)	0.0294 (6)	0.0542 (7)	0.0064 (5)	0.0113 (5)	0.0231 (5)
C9	0.0309 (6)	0.0316 (6)	0.0544 (7)	0.0117 (5)	0.0115 (5)	0.0258 (6)
C10	0.0264 (6)	0.0328 (6)	0.0438 (6)	0.0110 (5)	0.0087 (5)	0.0198 (5)
C11	0.0257 (6)	0.0349 (6)	0.0555 (7)	0.0102 (5)	0.0091 (5)	0.0260 (6)
C12	0.0267 (6)	0.0349 (6)	0.0487 (7)	0.0109 (5)	0.0096 (5)	0.0232 (5)
N1	0.0236 (5)	0.0308 (5)	0.0556 (6)	0.0075 (4)	0.0086 (5)	0.0260 (5)
N2	0.0254 (6)	0.0330 (6)	0.0542 (6)	0.0101 (4)	0.0083 (5)	0.0251 (5)
O1	0.0233 (5)	0.0473 (6)	0.0793 (7)	0.0063 (4)	0.0042 (4)	0.0374 (5)
O2	0.0239 (4)	0.0361 (5)	0.0798 (7)	0.0068 (4)	0.0052 (4)	0.0355 (5)
O3	0.0245 (4)	0.0337 (5)	0.0772 (6)	0.0086 (4)	0.0079 (4)	0.0334 (5)
O4	0.0295 (5)	0.0350 (5)	0.0742 (6)	0.0110 (4)	0.0116 (4)	0.0312 (5)
O5	0.0225 (5)	0.0434 (6)	0.0914 (8)	0.0105 (4)	0.0096 (5)	0.0402 (5)
O6	0.0232 (5)	0.0470 (5)	0.0826 (7)	0.0093 (4)	0.0093 (4)	0.0378 (5)
O7	0.0243 (4)	0.0391 (5)	0.0850 (7)	0.0088 (4)	0.0072 (4)	0.0391 (5)
O8	0.0259 (4)	0.0358 (5)	0.0805 (7)	0.0090 (4)	0.0077 (4)	0.0347 (5)
O9	0.0310 (5)	0.0437 (6)	0.0929 (8)	0.0116 (4)	0.0093 (5)	0.0437 (6)
O10	0.0241 (5)	0.0458 (6)	0.0951 (8)	0.0063 (4)	0.0074 (5)	0.0434 (6)

Geometric parameters (Å, º)

C1—O1	1.2196 (15)	C8—C9	1.3304 (18)
C1—O2	1.2977 (15)	C8—H8	0.9300
C1—C2	1.4864 (17)	C9—C10	1.4763 (17)
C2—C3	1.3294 (17)	C9—H9	0.9300
C2—H2A	0.9300	C10—O8	1.2483 (15)
C3—C4	1.4785 (17)	C10—N2	1.3211 (16)
C3—H3	0.9300	C11—N2	1.4444 (16)
C4—O3	1.2488 (15)	C11—C12	1.4983 (17)
C4—N1	1.3196 (16)	C11—H11A	0.9700
C5—N1	1.4459 (16)	C11—H11B	0.9700
C5—C6	1.4999 (17)	C12—O9	1.1963 (16)
C5—H5A	0.9700	C12—O10	1.3089 (16)
C5—H5B	0.9700	N1—H1X	0.814 (19)
C6—O4	1.2048 (15)	N2—H2Y	0.83 (2)
C6—O5	1.3083 (15)	O2—H2X	0.8200
C7—O6	1.2197 (16)	O5—H3X	0.97 (2)
C7—O7	1.2996 (15)	O7—H7X	0.8200
C7—C8	1.4851 (17)	O10—H10X	0.98 (2)
O1—C1—O2	119.35 (12)	C7—C8—H8	114.4
O1—C1—C2	119.79 (11)	C8—C9—C10	128.92 (11)
O2—C1—C2	120.86 (11)	C8—C9—H9	115.5
C3—C2—C1	131.26 (11)	C10—C9—H9	115.5
C3—C2—H2A	114.4	O8—C10—N2	119.96 (12)
C1—C2—H2A	114.4	O8—C10—C9	123.81 (11)
C2—C3—C4	128.65 (11)	N2—C10—C9	116.23 (11)
C2—C3—H3	115.7	N2—C11—C12	111.43 (11)
C4—C3—H3	115.7	N2—C11—H11A	109.3
O3—C4—N1	120.25 (11)	C12—C11—H11A	109.3
O3—C4—C3	123.57 (11)	N2—C11—H11B	109.3
N1—C4—C3	116.18 (11)	C12—C11—H11B	109.3
N1—C5—C6	110.85 (11)	H11A—C11—H11B	108.0
N1—C5—H5A	109.5	O9—C12—O10	124.84 (12)
C6—C5—H5A	109.5	O9—C12—C11	124.43 (12)
N1—C5—H5B	109.5	O10—C12—C11	110.72 (11)
C6—C5—H5B	109.5	C4—N1—C5	120.44 (11)
H5A—C5—H5B	108.1	C4—N1—H1X	121.7 (12)
O4—C6—O5	125.04 (11)	C5—N1—H1X	117.9 (13)
O4—C6—C5	124.12 (11)	C10—N2—C11	120.08 (11)
O5—C6—C5	110.84 (11)	C10—N2—H2Y	121.6 (13)
O6—C7—O7	119.47 (12)	C11—N2—H2Y	118.3 (13)
O6—C7—C8	119.56 (11)	C1—O2—H2X	109.5
O7—C7—C8	120.97 (11)	C6—O5—H3X	108.7 (12)
C9—C8—C7	131.11 (12)	C7—O7—H7X	109.5
C9—C8—H8	114.4	C12—O10—H10X	107.6 (12)

(emku145)

Crystal data

C5H6N2O4	Dx = 1.597 Mg m^−3
Mr = 158.12	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pbcn	Cell parameters from 1214 reflections
a = 10.4325 (8) Å	θ = 3.3–28.6°
b = 6.7755 (12) Å	µ = 0.14 mm^−1
c = 18.6056 (14) Å	T = 293 K
V = 1315.1 (3) Å^3	Block, colorless
Z = 8	0.42 × 0.38 × 0.31 mm
F(000) = 656

Data collection

Xcalibur, Eos, Gemini diffractometer	1345 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1124 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.024
ω scans	θmax = 26.4°, θmin = 2.9°
Absorption correction: multi-scan CrysAlis PRO, Agilent Technologies, Version 1.171.36.28 (release 01-02-2013 CrysAlis171 .NET) (compiled Feb 1 2013,16:14:44) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −12→13
Tmin = 0.944, Tmax = 0.958	k = −4→8
3214 measured reflections	l = −23→13

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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.140	H atoms treated by a mixture of independent and constrained refinement
S = 0.97	w = 1/[σ^2(Fo^2) + (0.1P)^2] where P = (Fo^2 + 2Fc^2)/3
1345 reflections	(Δ/σ)max = 0.001
109 parameters	Δρmax = 0.21 e Å^−3
0 restraints	Δρmin = −0.19 e Å^−3

Special details

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
H2A	0.138 (2)	0.136 (3)	0.2670 (12)	0.047 (6)*
H2B	0.146 (2)	0.201 (3)	0.1884 (14)	0.058 (7)*
C1	0.60903 (17)	0.4391 (3)	0.10008 (9)	0.0355 (5)
C2	0.55302 (17)	0.3068 (3)	0.04661 (9)	0.0377 (5)
H2	0.6013	0.2796	0.0058	0.045*
C3	0.43954 (17)	0.2232 (3)	0.05173 (10)	0.0363 (5)
H3	0.4168	0.1424	0.0134	0.044*
C4	0.34293 (16)	0.2388 (2)	0.10956 (9)	0.0321 (4)
C5	0.30376 (16)	0.1547 (3)	0.23569 (9)	0.0310 (4)
N1	0.38049 (14)	0.1807 (2)	0.17645 (7)	0.0315 (4)
H1	0.4609	0.1578	0.1822	0.038*
N2	0.17948 (14)	0.1686 (3)	0.22836 (10)	0.0396 (4)
O1	0.54714 (11)	0.5343 (2)	0.14280 (7)	0.0439 (4)
O2	0.73458 (11)	0.4433 (2)	0.09632 (7)	0.0476 (4)
H2C	0.7631	0.5083	0.1299	0.071*
O3	0.23415 (11)	0.2908 (2)	0.09558 (7)	0.0441 (4)
O4	0.35592 (11)	0.1137 (2)	0.29397 (6)	0.0404 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0298 (8)	0.0427 (10)	0.0341 (9)	−0.0012 (8)	0.0038 (7)	0.0033 (8)
C2	0.0363 (10)	0.0496 (11)	0.0274 (9)	0.0030 (9)	0.0030 (7)	−0.0024 (8)
C3	0.0366 (10)	0.0429 (10)	0.0295 (9)	0.0018 (8)	−0.0036 (7)	−0.0074 (8)
C4	0.0305 (9)	0.0339 (9)	0.0319 (9)	−0.0022 (7)	−0.0050 (7)	−0.0036 (7)
C5	0.0276 (8)	0.0334 (9)	0.0320 (9)	−0.0039 (7)	−0.0037 (7)	−0.0045 (7)
N1	0.0222 (7)	0.0404 (8)	0.0320 (8)	−0.0014 (6)	−0.0025 (6)	−0.0018 (6)
N2	0.0249 (8)	0.0571 (11)	0.0367 (9)	−0.0023 (7)	0.0000 (7)	0.0025 (8)
O1	0.0320 (7)	0.0521 (8)	0.0476 (8)	−0.0003 (6)	0.0047 (6)	−0.0122 (7)
O2	0.0299 (7)	0.0645 (10)	0.0484 (8)	−0.0074 (6)	0.0087 (5)	−0.0118 (7)
O3	0.0304 (7)	0.0626 (9)	0.0393 (7)	0.0075 (6)	−0.0062 (5)	0.0027 (6)
O4	0.0300 (7)	0.0603 (9)	0.0311 (7)	−0.0078 (6)	−0.0036 (5)	0.0008 (6)

Geometric parameters (Å, º)

C1—O1	1.210 (2)	C4—N1	1.363 (2)
C1—O2	1.312 (2)	C5—O4	1.245 (2)
C1—C2	1.461 (2)	C5—N2	1.307 (2)
C2—C3	1.316 (2)	C5—N1	1.373 (2)
C2—H2	0.9300	N1—H1	0.8600
C3—C4	1.478 (2)	N2—H2A	0.87 (2)
C3—H3	0.9300	N2—H2B	0.85 (3)
C4—O3	1.216 (2)	O2—H2C	0.8200
O1—C1—O2	123.76 (17)	N1—C4—C3	116.61 (15)
O1—C1—C2	124.12 (16)	O4—C5—N2	122.73 (17)
O2—C1—C2	112.12 (15)	O4—C5—N1	118.22 (15)
C3—C2—C1	125.07 (16)	N2—C5—N1	119.02 (16)
C3—C2—H2	117.5	C4—N1—C5	127.03 (15)
C1—C2—H2	117.5	C4—N1—H1	116.5
C2—C3—C4	129.44 (16)	C5—N1—H1	116.5
C2—C3—H3	115.3	C5—N2—H2A	112.9 (15)
C4—C3—H3	115.3	C5—N2—H2B	121.2 (18)
O3—C4—N1	123.17 (17)	H2A—N2—H2B	126 (2)
O3—C4—C3	120.09 (16)	C1—O2—H2C	109.5