supplementary materials


cv5410 scheme

Acta Cryst. (2013). E69, o952    [ doi:10.1107/S1600536813013561 ]

Acetoxy-[gamma]-valerolactone

C. Tristram, G. J. Gainsford and S. Hinkley

Abstract top

Levulinyl cellulose esters have been produced as an effective renewable binder for architectural coatings. The title compound, C7H10O4 (systematic name: 2-methyl-5-oxotetrahydrofuran-2-yl acetate), assigned as the esterifying species, was isolated and crystallized to confirm the structure. In the crystal, the molecules pack in layers parallel to (102) utilizing weak C-H...O interactions.

Comment top

Acetoxy-γ-valerolactone (2-methyl-5-oxotetrahydrofuran-2-yl acetate) was first described by Bredt (1886) and became of interest during our investigation of novel, renewable levulinyl cellulose esters. Esterification of cellulose in the presence of levulinic acid and an aliphatic anhydride affords a mixed cellulose levulinyl ester which we have shown has particular utility in architectural coatings [Glenny et al., 2012]. Levulinyl acetyl cellulose was generated by the sulfuric acid catalysed esterification of cellulose in the presence of acetic anhydride and levulinic acid. Analysis of this reaction mixture indicated that a valero-lactone species predominated rather than the anticipated mixture of anhydrides.

Acetoxy-γ-valerolactone was isolated by flash chromatography and identified as the major species in the reaction solution and has been assigned as the esterifying reagent. The generation of acetoxy-γ-valerolactone from acetic anhydride and levulinic acid had previously been reported (Rasmussen & Brattain, 1949) and also had been shown to be an esterifying agent forming levulinyl and acetyl amides (Suami & Day, 1959). When isolated in our hands, acetoxy-γ-valerolactone remained as a super cooled liquid, much like levulinic acid which exists as a light yellow solid or liquid, but will crystalize and displays a melting point between 30–33°C. Bell and Covington (1975) described the material as a solid with a melting point between 75–76°C but without supporting crystal structure data. The molecule was therefore crystallized from DCM and petroleum ether and the crystal structure elucidated. This confirmed the molecular structure and assisted with investigation into its esterification chemistry.

The title compound, C7H10O4, crystallizes with one unique molecule per asymetric unit. The five-membered ring adopts a flattened envelope conformation with O1 atom as a flap which deviates by 0.128 (1) Å from the mean plane P formed by the four C atoms. The acetate fragment is oriented in such a way that its mean plane and plane P are almost perpendicular to each other with an interplanar angle of 83.18 (7)°. There are no closely related structures in the Cambridge Structural Database, the closest being 5-(1-adamantyl)-5-ethoxytetrahydrofuran-2-one, LAGQUG (Cai et al., 2004).

In the crystal, weak CmethylH···Oacetate hydrogen bonds link the molecules into centrosymmetric dimers with the well known R22(8) motif (Bernstein et al., 1995), and weak Cmethylene—H···Oketone interactions (Table 1) link further these dimers into layers parallel to (102). Table 1.

Related literature top

For related structures, see: Cai et al. (2004). For hydrogen-bonding motifs, see: Bernstein et al. (1995). For background information, see: Bredt (1886); Rasmussen & Brattain (1949); Suami & Day (1959); Glenny et al. (2012). For a previous description of the title compound but without supporting crystal structure data, see: Bell & Covington (1975).

Experimental top

Levulinic acid (5.24 g, 45.1 mmol), acetic anhydride (3.46, 33.9 mmol) and concentrated sulfuric acid (12.9 mg, 129µmol) were placed in a 50 ml round bottom flask. The solution was heated to 120°C for 10 min with stirring, then quenched with 8 ml of a 5% Mg(OAc)2 solution in 50/50 acetic acid water. The reaction solution was extracted with DCM recovering an orange brown liquid. A portion of the recovered material was purified with flash chromatography; the column was packed with 40–63µm silica, (Davisil) to the dimensions of 110x35 mm. A gradient solvent system was used (petroleum ether/ethyl acetate 60/40 (400 ml), 50/50 (200 ml), 30/70 (200 ml), 10/90 (200 ml)) to separate and elute the 4-acetoxy-γ-valerolactone (Rf 0.42 in 60/40 petroleum ether/ethyl acetate). Suitable crystals were obtained by recrystallization from DCM and petroleum ether.

4-Acetoxy-γ-valerolactone m.p. 72–74°C (DSC): 1H NMR (500 MHz, CDCl3): δ 1.77 (s, H-3), 2.06 (s, H-1'), 2.31 (ddd, H-2, J 8.8, 10.6, 18.7 Hz), 2.61 (m, H-1 and H-2), 2.87 (ddd, H-1, J 7.75, 9.95, 17.6 Hz); 13C NMR δ 21.6 (C-1',OC(O)CH3), 26.1 (C-5,CCH3), 28.5 (C-2, CH2CH2), 32.7 (C-3, CH2C), 108.4 (C-4, Quaternary), 169.2 (C-1'), 175.4 (C-1); TOF-HRMS found 181.0472; [C7H10NaO4]+ calc. 181.0477.

Refinement top

All methyl H atoms were constrained to an ideal geometry (C—H = 0.98 Å) with Uiso(H) = 1.5Ueq(C), but were allowed to rotate freely about the adjacent C—C bond. All other C bound H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C—H distances of 0.99 Å and with Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: CrysAlis PRO (Agilent, 2013); cell refinement: CrysAlis PRO (Agilent, 2013); data reduction: CrysAlis PRO (Agilent, 2013); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2012 (Sheldrick, 2008); molecular graphics: ORTEP in WinGX (Farrugia, 2012); software used to prepare material for publication: SHELXL2012 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. ORTEP (Farrugia, 2012) view of the title molecule showing the atomic numbering and 50% probability displacement ellipsoids.
2-Methyl-5-oxotetrahydrofuran-2-yl acetate top
Crystal data top
C7H10O4F(000) = 336
Mr = 158.15Dx = 1.424 Mg m3
Monoclinic, P21/cCu Kα radiation, λ = 1.54184 Å
a = 5.86715 (15) ÅCell parameters from 3083 reflections
b = 12.7280 (3) Åθ = 5.7–73.5°
c = 10.2756 (3) ŵ = 1.00 mm1
β = 106.020 (3)°T = 120 K
V = 737.55 (3) Å3Block, colourless
Z = 40.19 × 0.12 × 0.07 mm
Data collection top
Agilent SuperNova (Dual, Cu at zero, Atlas)
diffractometer
1469 independent reflections
Radiation source: SuperNova (Cu) X-ray Source1350 reflections with I > 2σ(I)
Mirror monochromatorRint = 0.031
Detector resolution: 5.3250 pixels mm-1θmax = 73.8°, θmin = 5.7°
ω scansh = 77
Absorption correction: gaussian
(CrysAlis PRO; Agilent, 2013)
k = 1315
Tmin = 0.812, Tmax = 1.000l = 1212
4959 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.032Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.084H-atom parameters constrained
S = 1.03 w = 1/[σ2(Fo2) + (0.0434P)2 + 0.1941P]
where P = (Fo2 + 2Fc2)/3
1469 reflections(Δ/σ)max < 0.001
102 parametersΔρmax = 0.24 e Å3
0 restraintsΔρmin = 0.22 e Å3
Crystal data top
C7H10O4V = 737.55 (3) Å3
Mr = 158.15Z = 4
Monoclinic, P21/cCu Kα radiation
a = 5.86715 (15) ŵ = 1.00 mm1
b = 12.7280 (3) ÅT = 120 K
c = 10.2756 (3) Å0.19 × 0.12 × 0.07 mm
β = 106.020 (3)°
Data collection top
Agilent SuperNova (Dual, Cu at zero, Atlas)
diffractometer
1469 independent reflections
Absorption correction: gaussian
(CrysAlis PRO; Agilent, 2013)
1350 reflections with I > 2σ(I)
Tmin = 0.812, Tmax = 1.000Rint = 0.031
4959 measured reflectionsθmax = 73.8°
Refinement top
R[F2 > 2σ(F2)] = 0.032H-atom parameters constrained
wR(F2) = 0.084Δρmax = 0.24 e Å3
S = 1.03Δρmin = 0.22 e Å3
1469 reflectionsAbsolute structure: ?
102 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Experimental. Absorption correction: CrysAlis PRO (Agilent, 2013); numerical absorption correction based on gaussian integration over a multifaceted crystal model

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.25087 (13)0.23353 (6)0.37683 (8)0.01787 (19)
O20.01399 (17)0.10362 (7)0.27499 (9)0.0268 (2)
O30.32805 (14)0.40425 (6)0.32322 (8)0.0179 (2)
O40.04509 (15)0.35237 (6)0.13677 (8)0.0226 (2)
C10.4004 (2)0.36108 (9)0.55163 (11)0.0217 (3)
H1A0.35180.31850.61880.033*
H1B0.39590.43560.57470.033*
H1C0.56200.34180.55140.033*
C20.23376 (19)0.34162 (8)0.41354 (11)0.0166 (2)
C30.0297 (2)0.36272 (9)0.40270 (11)0.0187 (2)
H3A0.05260.37580.49320.022*
H3B0.08820.42430.34420.022*
C40.1589 (2)0.26306 (9)0.34032 (12)0.0206 (2)
H4A0.24620.23190.40070.025*
H4B0.27280.27850.25160.025*
C50.0322 (2)0.18993 (9)0.32378 (11)0.0187 (2)
C60.2205 (2)0.40306 (8)0.18841 (11)0.0185 (2)
C70.3555 (2)0.46800 (9)0.11343 (12)0.0236 (3)
H7A0.47080.42360.08620.035*
H7B0.43910.52450.17230.035*
H7C0.24510.49840.03270.035*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0182 (4)0.0148 (4)0.0212 (4)0.0003 (3)0.0065 (3)0.0008 (3)
O20.0346 (5)0.0185 (4)0.0294 (5)0.0052 (3)0.0121 (4)0.0058 (3)
O30.0204 (4)0.0174 (4)0.0163 (4)0.0029 (3)0.0059 (3)0.0013 (3)
O40.0262 (4)0.0233 (4)0.0172 (4)0.0041 (3)0.0043 (3)0.0009 (3)
C10.0218 (6)0.0257 (6)0.0163 (5)0.0040 (4)0.0032 (4)0.0019 (4)
C20.0191 (5)0.0141 (5)0.0173 (5)0.0015 (4)0.0061 (4)0.0007 (4)
C30.0189 (5)0.0184 (5)0.0197 (5)0.0003 (4)0.0069 (4)0.0021 (4)
C40.0182 (5)0.0211 (5)0.0223 (5)0.0024 (4)0.0054 (4)0.0022 (4)
C50.0219 (5)0.0185 (5)0.0163 (5)0.0031 (4)0.0065 (4)0.0011 (4)
C60.0229 (6)0.0160 (5)0.0170 (5)0.0022 (4)0.0064 (4)0.0004 (4)
C70.0293 (6)0.0226 (6)0.0207 (5)0.0026 (5)0.0099 (5)0.0023 (4)
Geometric parameters (Å, º) top
O1—C51.3660 (14)C3—C41.5253 (15)
O1—C21.4373 (13)C3—H3A0.9900
O2—C51.2000 (15)C3—H3B0.9900
O3—C61.3546 (14)C4—C51.5025 (16)
O3—C21.4443 (13)C4—H4A0.9900
O4—C61.2063 (15)C4—H4B0.9900
C1—C21.5049 (15)C6—C71.4972 (15)
C1—H1A0.9800C7—H7A0.9800
C1—H1B0.9800C7—H7B0.9800
C1—H1C0.9800C7—H7C0.9800
C2—C31.5424 (15)
C5—O1—C2111.57 (8)H3A—C3—H3B108.8
C6—O3—C2119.86 (8)C5—C4—C3105.24 (9)
C2—C1—H1A109.5C5—C4—H4A110.7
C2—C1—H1B109.5C3—C4—H4A110.7
H1A—C1—H1B109.5C5—C4—H4B110.7
C2—C1—H1C109.5C3—C4—H4B110.7
H1A—C1—H1C109.5H4A—C4—H4B108.8
H1B—C1—H1C109.5O2—C5—O1120.27 (11)
O1—C2—O3107.02 (8)O2—C5—C4129.16 (11)
O1—C2—C1109.32 (9)O1—C5—C4110.56 (9)
O3—C2—C1104.52 (9)O4—C6—O3123.78 (10)
O1—C2—C3106.79 (8)O4—C6—C7125.25 (10)
O3—C2—C3114.29 (9)O3—C6—C7110.90 (10)
C1—C2—C3114.62 (9)C6—C7—H7A109.5
C4—C3—C2104.93 (9)C6—C7—H7B109.5
C4—C3—H3A110.8H7A—C7—H7B109.5
C2—C3—H3A110.8C6—C7—H7C109.5
C4—C3—H3B110.8H7A—C7—H7C109.5
C2—C3—H3B110.8H7B—C7—H7C109.5
C5—O1—C2—O3112.79 (9)C1—C2—C3—C4128.27 (10)
C5—O1—C2—C1134.56 (9)C2—C3—C4—C52.08 (11)
C5—O1—C2—C310.02 (11)C2—O1—C5—O2172.31 (10)
C6—O3—C2—O162.87 (11)C2—O1—C5—C48.92 (12)
C6—O3—C2—C1178.76 (9)C3—C4—C5—O2177.45 (11)
C6—O3—C2—C355.15 (12)C3—C4—C5—O13.91 (12)
O1—C2—C3—C47.04 (11)C2—O3—C6—O40.50 (16)
O3—C2—C3—C4111.11 (10)C2—O3—C6—C7176.52 (9)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C3—H3B···O2i0.992.683.5827 (13)152
C1—H1B···O3ii0.982.633.4617 (14)142
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x+1, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C3—H3B···O2i0.992.683.5827 (13)152
C1—H1B···O3ii0.982.633.4617 (14)142.2
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x+1, y+1, z+1.
Acknowledgements top

We thank Dr Matthew Polson of the University of Canterbury, New Zealand, for the data collection.

references
References top

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