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organic compounds
N,N′-Dimethoxy-N,N′-dimethylsuccinamide
aMedical College of Henan University, Henan University, Kaifeng 475004, People's Republic of China
*Correspondence e-mail: ysum@yahoo.cn
The title compound, C8H16N2O4, is a Weinreb amide that is also an important intermediate for the preparation of and The molecule possesses a centre of symmetry.
Experimental
Crystal data
|
Data collection: SMART (Bruker, 2001); cell SMART; data reduction: SAINT-Plus (Bruker, 2001
); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008
); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008
); molecular graphics: PLATON (Spek, 2003
); software used to prepare material for publication: PLATON.
Supporting information
10.1107/S1600536808018369/at2577sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536808018369/at2577Isup2.hkl
Triethylamine (25 ml, 180 mmol) was added slowly by cannulation to a stirred suspension of N,O-dimethylhydroxylamine (9.0 g, 92.25 mmol) and succinyl chloride (100 ml) in dichloromethane at 273 K under N2. After stirring for 2 h the solution was allowed to warm to room temperature and quenched with saturated aqueous sodium bicarbonate solution (50 ml). The layers were separated and the aqueous layer was extracted with dichloromethane (2×25 ml). The combined organic extracts were washed with brine (18.5 ml), dried (MgSO4) and evaporated under reduced pressure to give the compound (I) (7.365 g, 83%) as light brown needles. The molecule formula, C8H16N2O4 was established by EIMS m/z:144(M+ –N(CH3)OCH3). Spectroscopic analysis, 1H NMR (400 MHz; CDCl3-d6) δ:3.75 (6H, s, OCH3), 3.19 (6H, s, NCH3) and 2.78 (4H, s, CH2); 13C NMR (400 MHz; CDCl3-d6) δ:173.8 (C=O), 61.6 (OCH3), 32.6 and 26.8.
H atoms were treated as riding, with C—H distances in the range of 0.96–0.97 Å, and were refined as riding with Uiso(H) =1.2Ueq(Cmethylene) and Uiso(H)=1.5Ueq(Cmethyl).
Data collection: SMART (Bruker, 2001); cell
SMART (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: PLATON (Spek, 2003). ![]() | Fig. 1. The molecular structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. |
C8H16N2O4 | F(000) = 220 |
Mr = 204.23 | Dx = 1.291 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 925 reflections |
a = 4.2645 (15) Å | θ = 2.6–26.6° |
b = 11.152 (4) Å | µ = 0.10 mm−1 |
c = 11.165 (4) Å | T = 296 K |
β = 98.485 (5)° | Block, yellow |
V = 525.2 (3) Å3 | 0.20 × 0.16 × 0.13 mm |
Z = 2 |
Bruker SMART APEX CCD area-detector diffractometer | 909 independent reflections |
Radiation source: fine-focus sealed tube | 776 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.015 |
ϕ and ω scans | θmax = 25.0°, θmin = 2.6° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2001) | h = −5→5 |
Tmin = 0.980, Tmax = 0.987 | k = −9→13 |
2116 measured reflections | l = −13→11 |
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)] = 0.055 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.174 | H-atom parameters constrained |
S = 1.01 | w = 1/[σ2(Fo2) + (0.117P)2 + 0.1547P] where P = (Fo2 + 2Fc2)/3 |
909 reflections | (Δ/σ)max < 0.001 |
64 parameters | Δρmax = 0.25 e Å−3 |
0 restraints | Δρmin = −0.24 e Å−3 |
C8H16N2O4 | V = 525.2 (3) Å3 |
Mr = 204.23 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 4.2645 (15) Å | µ = 0.10 mm−1 |
b = 11.152 (4) Å | T = 296 K |
c = 11.165 (4) Å | 0.20 × 0.16 × 0.13 mm |
β = 98.485 (5)° |
Bruker SMART APEX CCD area-detector diffractometer | 909 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2001) | 776 reflections with I > 2σ(I) |
Tmin = 0.980, Tmax = 0.987 | Rint = 0.015 |
2116 measured reflections |
R[F2 > 2σ(F2)] = 0.055 | 0 restraints |
wR(F2) = 0.174 | H-atom parameters constrained |
S = 1.01 | Δρmax = 0.25 e Å−3 |
909 reflections | Δρmin = −0.24 e Å−3 |
64 parameters |
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 | 0.2198 (3) | 0.51856 (11) | 0.21773 (11) | 0.0633 (4) | |
O2 | 0.4066 (3) | 0.76550 (10) | 0.05213 (10) | 0.0498 (3) | |
N1 | 0.3748 (4) | 0.69395 (13) | 0.15260 (12) | 0.0525 (4) | |
C1 | 0.2269 (4) | 0.58794 (14) | 0.13325 (15) | 0.0434 (4) | |
C2 | 0.0721 (4) | 0.56191 (14) | 0.00580 (15) | 0.0452 (4) | |
H2A | 0.2289 | 0.5689 | −0.0485 | 0.054* | |
H2B | −0.0920 | 0.6210 | −0.0183 | 0.054* | |
C3 | 0.2116 (5) | 0.87038 (16) | 0.0512 (2) | 0.0643 (6) | |
H3A | 0.2351 | 0.9186 | −0.0181 | 0.096* | |
H3B | 0.2754 | 0.9159 | 0.1237 | 0.096* | |
H3C | −0.0061 | 0.8468 | 0.0475 | 0.096* | |
C4 | 0.5720 (5) | 0.72712 (18) | 0.26424 (17) | 0.0616 (5) | |
H4A | 0.5347 | 0.6728 | 0.3274 | 0.092* | |
H4B | 0.5214 | 0.8073 | 0.2861 | 0.092* | |
H4C | 0.7910 | 0.7232 | 0.2535 | 0.092* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0974 (10) | 0.0429 (6) | 0.0457 (7) | −0.0074 (6) | −0.0023 (6) | 0.0066 (5) |
O2 | 0.0637 (7) | 0.0412 (6) | 0.0458 (7) | −0.0059 (5) | 0.0127 (5) | 0.0014 (5) |
N1 | 0.0754 (9) | 0.0421 (7) | 0.0376 (8) | −0.0108 (7) | 0.0004 (7) | −0.0014 (6) |
C1 | 0.0550 (9) | 0.0329 (7) | 0.0413 (9) | 0.0029 (6) | 0.0035 (7) | 0.0003 (7) |
C2 | 0.0568 (9) | 0.0341 (8) | 0.0425 (9) | −0.0008 (7) | 0.0003 (7) | −0.0004 (7) |
C3 | 0.0740 (12) | 0.0423 (10) | 0.0760 (13) | −0.0006 (8) | 0.0094 (10) | 0.0030 (9) |
C4 | 0.0767 (12) | 0.0605 (11) | 0.0445 (10) | −0.0137 (9) | −0.0015 (9) | −0.0093 (9) |
O1—C1 | 1.2238 (19) | C2—H2B | 0.9700 |
O2—N1 | 1.3994 (18) | C3—H3A | 0.9600 |
O2—C3 | 1.434 (2) | C3—H3B | 0.9600 |
N1—C1 | 1.342 (2) | C3—H3C | 0.9600 |
N1—C4 | 1.445 (2) | C4—H4A | 0.9600 |
C1—C2 | 1.506 (2) | C4—H4B | 0.9600 |
C2—C2i | 1.510 (3) | C4—H4C | 0.9600 |
C2—H2A | 0.9700 | ||
N1—O2—C3 | 110.25 (13) | O2—C3—H3A | 109.5 |
C1—N1—O2 | 118.16 (13) | O2—C3—H3B | 109.5 |
C1—N1—C4 | 124.34 (15) | H3A—C3—H3B | 109.5 |
O2—N1—C4 | 115.63 (14) | O2—C3—H3C | 109.5 |
O1—C1—N1 | 119.82 (15) | H3A—C3—H3C | 109.5 |
O1—C1—C2 | 123.31 (15) | H3B—C3—H3C | 109.5 |
N1—C1—C2 | 116.87 (14) | N1—C4—H4A | 109.5 |
C1—C2—C2i | 111.95 (17) | N1—C4—H4B | 109.5 |
C1—C2—H2A | 109.2 | H4A—C4—H4B | 109.5 |
C2i—C2—H2A | 109.2 | N1—C4—H4C | 109.5 |
C1—C2—H2B | 109.2 | H4A—C4—H4C | 109.5 |
C2i—C2—H2B | 109.2 | H4B—C4—H4C | 109.5 |
H2A—C2—H2B | 107.9 | ||
C3—O2—N1—C1 | 110.95 (17) | O2—N1—C1—C2 | −7.3 (2) |
C3—O2—N1—C4 | −83.94 (19) | C4—N1—C1—C2 | −171.05 (17) |
O2—N1—C1—O1 | 173.52 (15) | O1—C1—C2—C2i | −3.6 (3) |
C4—N1—C1—O1 | 9.8 (3) | N1—C1—C2—C2i | 177.24 (18) |
Symmetry code: (i) −x, −y+1, −z. |
Experimental details
Crystal data | |
Chemical formula | C8H16N2O4 |
Mr | 204.23 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 296 |
a, b, c (Å) | 4.2645 (15), 11.152 (4), 11.165 (4) |
β (°) | 98.485 (5) |
V (Å3) | 525.2 (3) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.20 × 0.16 × 0.13 |
Data collection | |
Diffractometer | Bruker SMART APEX CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2001) |
Tmin, Tmax | 0.980, 0.987 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2116, 909, 776 |
Rint | 0.015 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.055, 0.174, 1.01 |
No. of reflections | 909 |
No. of parameters | 64 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.25, −0.24 |
Computer programs: SMART (Bruker, 2001), SAINT-Plus (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2003).
References
Bruker (2001). SAINT-Plus and SMART. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Nahm, S. & Weinreb, S. M. (1981). Tetrahedron Lett. 22, 3815–3818. CrossRef CAS Web of Science Google Scholar
Sheldrick, G. M. (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13. Web of Science CrossRef CAS IUCr Journals Google Scholar
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The Weinreb amides are widely recognized as effective acylating agents since they react with organometallics (RM, M = MgBr, Li) to produce ketones without side products in organic synthesis, including the total synthesis of complex natural products (Nahm & Weinreb, 1981). We here reported the structure of the Weinreb amides related title compound, (I).
Compound (I), is the synthetic intermediate, whose molecule is the centrosymmetric structure (Fig.1). In the symmetric unit, the C1—O1 bond distance is 1.224 (2) Å, which displays a typical double-bond of ketone carbonyl. Whereas, the N1—C1 bond distance of 1.342 (2) Å is obviously shorter than N1—C4 of 1.445 (2) Å, indicates that amide bond N1—C1 has some proporties of double-bond.