L-Methio­ninamide ester amide of squaric acid diethyl ester

Mol­ecules of the title compound, 2-(2-eth­oxy-3,4-dioxocyclo­butenylamino)-2-[2-(methyl­sulfan­yl)eth­yl]acetamide, C₁₁H₁₆N₂O₄S, are connected into chains in the [010] direction by inter­molecular N—H...O hydrogen bonds involving the L-methio­ninamide N atoms and its carbonyl O atom.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.047
• wR factor = 0.122
• Data-to-parameter ratio = 9.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       2.66 Ratio
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.33 Ratio
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         S5
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          6
PLAT360_ALERT_2_C Short  C(sp3)-C(sp3) Bond  C22    -   C23    ...       1.43 Ang.

Alert level G
REFLT03_ALERT_4_G  WARNING: Large fraction of Friedel related reflns may
                     be needed to determine absolute structure
           From the CIF: _diffrn_reflns_theta_max           25.00
           From the CIF: _reflns_number_total               1487
           Count of symmetry unique reflns         1309
           Completeness (_total/calc)            113.60%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       178
           Fraction of Friedel pairs measured     0.136
           Are heavy atom types Z>Si present        yes

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

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 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: R3m/V User's Guide (Siemens, 1989); cell refinement: R3m/V User's Guide; data reduction: XDISK (Siemens, 1989); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL-Plus (Sheldrick, 1995); software used to prepare material for publication: SHELXL97.

2-(2-ethoxy-3,4-dioxocyclobutenylamino)-2-[2-(methylsulfanyl)ethyl]acetamide

Crystal data

C11H16N2O4S	F(000) = 288
Mr = 272.32	Dx = 1.320 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 25 reflections
a = 9.5810 (11) Å	θ = 7.3–15.1°
b = 7.3961 (12) Å	µ = 0.25 mm^−1
c = 9.9354 (13) Å	T = 294 K
β = 103.355 (7)°	Prism, colourless
V = 685.00 (16) Å^3	0.55 × 0.48 × 0.22 mm
Z = 2

Data collection

Siemens P4 four-circle diffractometer	1294 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.026
Graphite monochromator	θmax = 25.0°, θmin = 2.1°
ω scans	h = −1→11
Absorption correction: ψ scan (XPREP in SHELXTL-Plus; Sheldrick, 1995)	k = −1→8
Tmin = 0.873, Tmax = 0.948	l = −11→11
1754 measured reflections	3 standard reflections every 100 reflections
1487 independent reflections	intensity decay: 1%

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)] = 0.047	w = 1/[σ^2(Fo^2) + (0.0523P)^2 + 0.2827P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.122	(Δ/σ)max = 0.009
S = 1.05	Δρmax = 0.22 e Å^−3
1487 reflections	Δρmin = −0.17 e Å^−3
166 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
1 restraint	Extinction coefficient: 0.09 (2)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 204 Friedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.05 (19)

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
S5	0.97550 (17)	0.8273 (3)	0.3709 (2)	0.1172 (8)
N1	0.4899 (3)	0.6818 (5)	0.2881 (3)	0.0478 (7)
H1	0.4851	0.7415	0.3612	0.057*
C2	0.5937 (4)	0.5346 (5)	0.3005 (3)	0.0434 (8)
H2	0.5958	0.4910	0.2078	0.052*
C3	0.5512 (4)	0.3810 (5)	0.3826 (3)	0.0458 (8)
O3	0.4984 (3)	0.4123 (4)	0.4823 (2)	0.0607 (7)
N3	0.5765 (4)	0.2159 (5)	0.3471 (4)	0.0711 (11)
H31	0.5563	0.1257	0.3938	0.085*
H32	0.6134	0.1977	0.2772	0.085*
C4	0.7446 (4)	0.6025 (7)	0.3733 (4)	0.0578 (10)
H41	0.7423	0.6472	0.4646	0.069*
H42	0.8115	0.5021	0.3850	0.069*
C5	0.7972 (5)	0.7507 (7)	0.2933 (5)	0.0777 (13)
H51	0.7319	0.8525	0.2849	0.093*
H52	0.7950	0.7072	0.2007	0.093*
C6	1.0783 (5)	0.6383 (12)	0.3374 (7)	0.112 (2)
H61	1.0560	0.6137	0.2399	0.168*
H62	1.0556	0.5344	0.3861	0.168*
H63	1.1787	0.6653	0.3681	0.168*
C11	0.4032 (3)	0.7270 (5)	0.1696 (3)	0.0467 (9)
C21	0.2954 (4)	0.8570 (6)	0.1321 (4)	0.0550 (10)
O21	0.2525 (3)	0.9785 (5)	0.2109 (3)	0.0745 (9)
C22	0.1421 (6)	1.1085 (8)	0.1421 (7)	0.1005 (19)
H221	0.0914	1.0600	0.0536	0.121*
H222	0.0732	1.1268	0.1986	0.121*
C23	0.2061 (7)	1.2776 (9)	0.1213 (8)	0.115 (2)
H231	0.2864	1.2568	0.0807	0.173*
H232	0.2382	1.3378	0.2085	0.173*
H233	0.1368	1.3517	0.0605	0.173*
C31	0.2645 (4)	0.8066 (7)	−0.0141 (4)	0.0701 (13)
O31	0.1840 (4)	0.8543 (7)	−0.1222 (3)	0.1074 (15)
C41	0.3823 (4)	0.6687 (7)	0.0247 (3)	0.0617 (12)
O41	0.4388 (3)	0.5639 (6)	−0.0381 (3)	0.0878 (12)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S5	0.0940 (10)	0.1169 (15)	0.1514 (15)	−0.0515 (10)	0.0500 (10)	−0.0496 (12)
N1	0.0562 (15)	0.0503 (18)	0.0375 (13)	0.0118 (15)	0.0123 (12)	0.0060 (14)
C2	0.0462 (17)	0.048 (2)	0.0376 (15)	0.0071 (16)	0.0139 (13)	0.0048 (16)
C3	0.0493 (18)	0.048 (2)	0.0403 (16)	0.0008 (18)	0.0116 (14)	0.0011 (17)
O3	0.0907 (17)	0.0498 (16)	0.0515 (14)	−0.0026 (16)	0.0370 (13)	−0.0001 (13)
N3	0.114 (3)	0.048 (2)	0.0649 (19)	0.015 (2)	0.049 (2)	0.0120 (18)
C4	0.0516 (19)	0.067 (3)	0.0562 (19)	−0.003 (2)	0.0145 (16)	0.0048 (19)
C5	0.070 (3)	0.065 (3)	0.102 (3)	−0.006 (3)	0.028 (2)	0.010 (3)
C6	0.066 (3)	0.138 (6)	0.141 (5)	−0.006 (4)	0.042 (3)	0.018 (5)
C11	0.0445 (16)	0.049 (2)	0.0477 (17)	−0.0024 (17)	0.0137 (14)	0.0127 (17)
C21	0.0488 (19)	0.053 (2)	0.062 (2)	−0.0034 (19)	0.0091 (16)	0.022 (2)
O21	0.0693 (18)	0.0584 (19)	0.092 (2)	0.0153 (16)	0.0104 (15)	0.0126 (18)
C22	0.065 (3)	0.069 (3)	0.159 (5)	0.023 (3)	0.008 (3)	0.030 (4)
C23	0.110 (4)	0.074 (4)	0.143 (5)	0.023 (4)	−0.007 (4)	0.016 (4)
C31	0.057 (2)	0.082 (3)	0.065 (2)	−0.018 (2)	0.0002 (19)	0.030 (2)
O31	0.096 (2)	0.128 (4)	0.0764 (19)	−0.015 (3)	−0.0248 (17)	0.048 (2)
C41	0.060 (2)	0.083 (3)	0.0428 (19)	−0.013 (2)	0.0125 (17)	0.009 (2)
O41	0.088 (2)	0.126 (3)	0.0520 (15)	0.001 (2)	0.0207 (14)	−0.014 (2)

Geometric parameters (Å, º)

S5—C6	1.785 (8)	C6—H61	0.9600
S5—C5	1.796 (5)	C6—H62	0.9600
N1—C11	1.317 (4)	C6—H63	0.9600
N1—C2	1.461 (5)	C11—C21	1.397 (5)
N1—H1	0.8600	C11—C41	1.472 (5)
C2—C3	1.508 (5)	C21—O21	1.318 (5)
C2—C4	1.544 (5)	C21—C31	1.462 (6)
C2—H2	0.9800	O21—C22	1.475 (6)
C3—O3	1.233 (4)	C22—C23	1.428 (9)
C3—N3	1.309 (5)	C22—H221	0.9700
N3—H31	0.8600	C22—H222	0.9700
N3—H32	0.8600	C23—H231	0.9600
C4—C5	1.508 (6)	C23—H232	0.9600
C4—H41	0.9700	C23—H233	0.9600
C4—H42	0.9700	C31—O31	1.221 (5)
C5—H51	0.9700	C31—C41	1.504 (7)
C5—H52	0.9700	C41—O41	1.200 (6)
C6—S5—C5	100.6 (3)	H61—C6—H62	109.5
C11—N1—C2	122.7 (3)	S5—C6—H63	109.5
C11—N1—H1	118.6	H61—C6—H63	109.5
C2—N1—H1	118.6	H62—C6—H63	109.5
N1—C2—C3	110.1 (3)	N1—C11—C21	133.4 (3)
N1—C2—C4	110.0 (3)	N1—C11—C41	135.6 (4)
C3—C2—C4	109.4 (3)	C21—C11—C41	90.9 (3)
N1—C2—H2	109.1	O21—C21—C11	128.6 (3)
C3—C2—H2	109.1	O21—C21—C31	138.1 (4)
C4—C2—H2	109.1	C11—C21—C31	93.3 (4)
O3—C3—N3	121.8 (3)	C21—O21—C22	117.3 (4)
O3—C3—C2	120.3 (3)	C23—C22—O21	110.6 (5)
N3—C3—C2	117.8 (3)	C23—C22—H221	109.5
C3—N3—H31	120.0	O21—C22—H221	109.5
C3—N3—H32	120.0	C23—C22—H222	109.5
H31—N3—H32	120.0	O21—C22—H222	109.5
C5—C4—C2	112.4 (3)	H221—C22—H222	108.1
C5—C4—H41	109.1	C22—C23—H231	109.5
C2—C4—H41	109.1	C22—C23—H232	109.5
C5—C4—H42	109.1	H231—C23—H232	109.5
C2—C4—H42	109.1	C22—C23—H233	109.5
H41—C4—H42	107.9	H231—C23—H233	109.5
C4—C5—S5	113.8 (3)	H232—C23—H233	109.5
C4—C5—H51	108.8	O31—C31—C21	137.9 (5)
S5—C5—H51	108.8	O31—C31—C41	134.9 (5)
C4—C5—H52	108.8	C21—C31—C41	87.2 (3)
S5—C5—H52	108.8	O41—C41—C11	136.3 (4)
H51—C5—H52	107.7	O41—C41—C31	135.0 (4)
S5—C6—H61	109.5	C11—C41—C31	88.6 (4)
S5—C6—H62	109.5

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O3^i	0.86	1.98	2.829 (4)	169
N3—H31···O3^ii	0.86	2.14	2.999 (4)	177
N3—H32···O41^iii	0.86	2.51	3.241 (5)	143

Symmetry codes: (i) −x+1, y+1/2, −z+1; (ii) −x+1, y−1/2, −z+1; (iii) −x+1, y−1/2, −z.