Meth­yl acetoacetate at 150 K

Shallard-Brown, H.A.; Watkin, D.J.; Cowley, A.R.

doi:10.1107/S1600536805017654

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 61| Part 8| August 2005| Pages o2422-o2423

https://doi.org/10.1107/S1600536805017654

Methyl acetoacetate at 150 K

Howard A. Shallard-Brown,^a ^* David J. Watkin ^a and Andrew R. Cowley ^a

^aChemical Crystallography Laboratory, Chemistry Research Laboratory, Mansfield Road, Oxford University, Oxford OX1 3TA, England
^*Correspondence e-mail: howard.shallard-brown@lmh.ox.ac.uk

(Received 20 May 2005; accepted 3 June 2005; online 9 July 2005)

The crystal structure of methyl acetoacetate, C₅H₈O₃, at 150 K contains discrete molecules.

Comment

Many of the esters and ketones used in the flavours and fragrances industry are liquid at room temperature, meaning that in the past crystalline derivatives have had to be prepared for X-ray analysis. As part of a programme to systematize in situ crystal growth from liquids, we have examined a range of commercially available chemicals. Low-molecular-weight organic ketones are liquid at room temperature. Molecules of methyl acetoacetate, (I), exist as discrete entities in the crystal structure at 150 K, with no strong intermolecular interactions.

Figure 1
The title compound, with displacement ellipsoids drawn at the 50% probability level. H atoms are of arbitrary radii.

Figure 2
The crystal structure, viewed down the a axis.

Figure 3
The crystal structure, viewed down the b axis.

Experimental

A 3 mm column of the title material, which is a liquid at room temperature, was sealed in a 0.3 mm Lindemann tube. The Lindemann tube was not precisely parallel to the φ axis. A single crystal of the compound was grown by keeping the sample under a stream of nitrogen gas (Oxford Cryostream 600) at 180 K and slowly moving a small liquid zone, created by a micro-heating coil, up and down the sample. Once a suitable approximately single-crystal specimen had been obtained, the main data collection was carried out at 150 K. Because not all the data were collected with the Lindemann tube perpendicular to the X-ray beam, the multi-scan corrections applied by DENZO/SCALEPACK (Otwinowski & Minor, 1997 ) also contain contributions due to changes in the illuminated volume of the cylindrical sample, which affects the value of T_min/T_max.

Crystal data

C₅H₈O₃
M_r = 116.12
Monoclinic, P 12₁ /c 1
a = 6.0018 (2) Å
b = 8.0384 (3) Å
c = 12.4802 (3) Å
β = 95.5132 (17)°
V = 599.32 (3) Å³
Z = 4
D_x = 1.287 Mg m⁻³
Mo Kα radiation
Cell parameters from 1392 reflections
θ = 5–27°
μ = 0.11 mm⁻¹
T = 150 K
Cylinder, colourless
0.70 × 0.30 × 0.30 mm

Data collection

Nonius KappaCCD diffractometer
ω scans
Absorption correction: multi-scan(DENZO/SCALEPACK; Otwinowski & Minor, 1997)T_min = 0.68, T_max = 0.95
2531 measured reflections
1343 independent reflections
1184 reflections with I > 2σ(I)
R_int = 0.022
θ_max = 27.5°
h = −7 → 7
k = −10 → 10
l = −16 → 16

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.036
wR(F²) = 0.095
S = 1.01
1343 reflections
106 parameters
Only H-atom coordinates refined
w = 1/[σ²(F) + 0.04 + 0.19P] where P = [max(F_o², 0) + 2F_c²]/3
(Δ/σ)_max < 0.001
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

C1—C2	1.5001 (15)
C1—O6	1.3328 (14)
C1—O8	1.1997 (14)
C2—C3	1.5191 (15)
C3—O4	1.2118 (13)
C3—C5	1.4920 (15)
O6—C7	1.4458 (14)

C2—C1—O6	111.96 (9)
C2—C1—O8	124.51 (11)
O6—C1—O8	123.53 (10)
C1—C2—C3	112.28 (9)
C2—C3—O4	121.15 (10)
C2—C3—C5	115.27 (9)
O4—C3—C5	123.58 (10)
C1—O6—C7	116.27 (9)

All H atoms were located in a difference map. Alternative positions were clearly visible for the disordered H atoms on C7, whose site occupancy factors were set to 0.5. The H atoms were then repositioned geometrically and refined with soft restraints on the bond lengths and angles to regularize their geometry, with C—H = 0.97–1.01 Å, and U_iso(H) = 1.2U_eq(C), after which the restraints were removed.

Data collection: COLLECT (Nonius, 1997 ); cell refinement: DENZO/SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO/SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1994 ); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003 ); molecular graphics: CAMERON (Watkin et al., 1996 ); software used to prepare material for publication: CRYSTALS.

Supporting information

Crystal structure: contains datablocks I, CRYSTALS_cif. DOI: https://doi.org/10.1107/S1600536805017654/cf6428sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536805017654/cf6428Isup2.hkl

Computing details top

Data collection: COLLECT (Nonius, 1997); cell refinement: DENZO/SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO/SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: CAMERON (Watkin et al., 1996); software used to prepare material for publication: CRYSTALS.

(I) top

Crystal data top

C₅H₈O₃	F(000) = 248
M_r = 116.12	D_x = 1.287 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 6.0018 (2) Å	Cell parameters from 1392 reflections
b = 8.0384 (3) Å	θ = 5–27°
c = 12.4802 (3) Å	µ = 0.11 mm⁻¹
β = 95.5132 (17)°	T = 150 K
V = 599.32 (3) Å³	Cylinder, colourless
Z = 4	0.70 × 0.30 × 0.30 × 0.30 (radius) mm

Data collection top

Nonius KappaCCD diffractometer	1184 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.022
ω scans	θ_max = 27.5°, θ_min = 5.5°
Absorption correction: multi-scan (DENZO/SCALEPACK; Otwinowski & Minor, 1997)	h = −7→7
T_min = 0.68, T_max = 0.95	k = −10→10
2531 measured reflections	l = −16→16
1343 independent reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.036	Only H-atom coordinates refined
wR(F²) = 0.095	w = 1/[σ²(F) + 0.04 + 0.19P] where P = (max(F_o², 0) + 2F_c²)/3
S = 1.01	(Δ/σ)_max = 0.000179
1343 reflections	Δρ_max = 0.25 e Å⁻³
106 parameters	Δρ_min = −0.22 e Å⁻³
34 restraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
C1	0.98275 (18)	0.27935 (14)	0.16468 (9)	0.0295
C2	0.8961 (2)	0.29879 (15)	0.27279 (9)	0.0326
C3	0.71045 (17)	0.42745 (13)	0.27155 (8)	0.0266
O4	0.68130 (14)	0.52847 (11)	0.19950 (7)	0.0377
C5	0.5717 (2)	0.41962 (18)	0.36442 (10)	0.0374
O6	1.15380 (13)	0.38125 (11)	0.15274 (6)	0.0336
C7	1.2470 (2)	0.3743 (2)	0.05022 (10)	0.0447
O8	0.90835 (17)	0.18382 (13)	0.09654 (8)	0.0499
H21	0.839 (2)	0.1936 (17)	0.2936 (10)	0.0468*
H22	1.014 (2)	0.3354 (17)	0.3247 (11)	0.0469*
H51	0.472 (3)	0.5128 (19)	0.3641 (12)	0.0651*
H52	0.489 (3)	0.3144 (18)	0.3609 (12)	0.0660*
H53	0.669 (2)	0.418 (2)	0.4325 (11)	0.0652*
H71	1.382 (4)	0.438 (4)	0.056 (2)	0.0803*	0.5000
H72	1.138 (4)	0.411 (4)	−0.0067 (17)	0.0792*	0.5000
H73	1.281 (5)	0.259 (2)	0.037 (2)	0.0794*	0.5000
H74	1.366 (4)	0.295 (3)	0.054 (2)	0.0796*	0.5000
H75	1.307 (5)	0.485 (3)	0.040 (2)	0.0798*	0.5000
H76	1.131 (4)	0.348 (4)	−0.0065 (17)	0.0794*	0.5000

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0310 (5)	0.0281 (5)	0.0297 (5)	0.0021 (4)	0.0038 (4)	0.0019 (4)
C2	0.0367 (6)	0.0318 (6)	0.0303 (6)	0.0053 (5)	0.0082 (4)	0.0072 (4)
C3	0.0264 (5)	0.0263 (5)	0.0266 (5)	−0.0032 (4)	0.0006 (4)	0.0000 (4)
O4	0.0381 (5)	0.0357 (5)	0.0392 (5)	0.0039 (4)	0.0035 (3)	0.0119 (4)
C5	0.0353 (6)	0.0451 (7)	0.0326 (6)	0.0034 (5)	0.0082 (5)	0.0002 (5)
O6	0.0342 (4)	0.0409 (5)	0.0266 (4)	−0.0062 (3)	0.0067 (3)	−0.0018 (3)
C7	0.0391 (7)	0.0651 (9)	0.0316 (6)	−0.0047 (6)	0.0119 (5)	−0.0002 (6)
O8	0.0563 (6)	0.0516 (6)	0.0426 (5)	−0.0191 (5)	0.0090 (4)	−0.0136 (4)

Geometric parameters (Å, º) top

C1—C2	1.5001 (15)	C5—H52	0.978 (14)
C1—O6	1.3328 (14)	C5—H53	0.983 (13)
C1—O8	1.1997 (14)	O6—C7	1.4458 (14)
C2—C3	1.5191 (15)	C7—H71	0.958 (18)
C2—H21	0.957 (13)	C7—H72	0.965 (18)
C2—H22	0.960 (13)	C7—H73	0.970 (18)
C3—O4	1.2118 (13)	C7—H74	0.957 (18)
C3—C5	1.4920 (15)	C7—H75	0.973 (18)
C5—H51	0.958 (14)	C7—H76	0.969 (18)

C2—C1—O6	111.96 (9)	H51—C5—H53	109.4 (12)
C2—C1—O8	124.51 (11)	H52—C5—H53	106.4 (12)
O6—C1—O8	123.53 (10)	C1—O6—C7	116.27 (9)
C1—C2—C3	112.28 (9)	O6—C7—H71	108.2 (14)
C1—C2—H21	108.4 (8)	O6—C7—H72	110.3 (15)
C3—C2—H21	108.9 (8)	H71—C7—H72	113.4 (16)
C1—C2—H22	110.0 (8)	O6—C7—H73	107.2 (14)
C3—C2—H22	107.0 (8)	H71—C7—H73	109.5 (16)
H21—C2—H22	110.4 (11)	H72—C7—H73	108.0 (16)
C2—C3—O4	121.15 (10)	O6—C7—H74	109.6 (15)
C2—C3—C5	115.27 (9)	O6—C7—H75	105.2 (15)
O4—C3—C5	123.58 (10)	H74—C7—H75	109.3 (16)
C3—C5—H51	111.0 (9)	O6—C7—H76	110.0 (15)
C3—C5—H52	108.6 (9)	H74—C7—H76	111.9 (16)
H51—C5—H52	111.2 (11)	H75—C7—H76	110.6 (16)
C3—C5—H53	110.0 (9)

References

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