1-Benzyl-2,5-dioxopyrrolidine-3,4-diyl diacetate

Caracelli, I.; Ferreira, F.P.; Vieira, A.S.; Stefani, H.A.; De Simone, C.A.; Tiekink, E.R.T.

doi:10.1107/S1600536810043187

organic compounds

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ISSN: 2056-9890

Volume 66| Part 12| December 2010| Page o3044

https://doi.org/10.1107/S1600536810043187

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1-Benzyl-2,5-dioxopyrrolidine-3,4-diyl diacetate

Ignez Caracelli,^a ^* Fernando P. Ferreira,^b Adriano S. Vieira,^b Hélio A. Stefani,^b Carlos A. De Simone ^c and Edward R. T. Tiekink ^d

^aPhysics Department, Universidade Federal de São Carlos, 13565-905 São Carlos, SP, Brazil, ^bDepartamento de Farmácia, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, SP, Brazil, ^cInstituto de Química e Biotecnologia, Universidade Federal de Alagoas, 57072-970 Maceió, AL, Brazil, and ^dDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
^*Correspondence e-mail: ignez@ufscar.br

(Received 21 October 2010; accepted 22 October 2010; online 6 November 2010)

The pyrrolidine-2,5-dione ring in the title compound, C₁₅H₁₅NO₆, is in a twisted conformation with the acetyl C atoms projecting to opposite sides of the ring. The acetyl groups lie to opposite sides of the five-membered ring. The benzene ring is roughly perpendicular to the heterocyclic ring, forming a dihedral angle of 76.57 (14)° with it. In the crystal, molecules are connected through a network of C—H⋯O and C—H⋯π interactions.

Related literature

For the use of N-acyliminium in organic synthesis, see: Vieira et al. (2008 ); Huang (2006 ); Russo et al. (2010 ). For background to the synthesis, see: Caracelli et al. (2010 ). For a related structure, see: Naz et al. (2009 ). For conformational analysis, see: Cremer & Pople (1975 ); Iulek & Zukerman-Schpector (1997 ).

Experimental

Crystal data

C₁₅H₁₅NO₆
M_r = 305.28
Orthorhombic, P 2₁ 2₁ 2₁
a = 8.8498 (4) Å
b = 9.8107 (4) Å
c = 17.5148 (6) Å
V = 1520.68 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 290 K
0.28 × 0.23 × 0.06 mm

Data collection

Bruker SMART APEXII diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.962, T_max = 0.991
7672 measured reflections
1541 independent reflections
1396 reflections with I > 2σ(I)
R_int = 0.122

Refinement

R[F² > 2σ(F²)] = 0.036
wR(F²) = 0.085
S = 1.07
1541 reflections
202 parameters
H-atom parameters constrained
Δρ_max = 0.12 e Å⁻³
Δρ_min = −0.12 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2⋯O3ⁱ	0.98	2.51	3.206 (2)	128
C3—H3⋯O1ⁱⁱ	0.98	2.55	3.276 (3)	131
C5—H5b⋯O6ⁱⁱⁱ	0.97	2.49	3.328 (3)	144
C13—H13b⋯Cg1ⁱⁱ	0.96	2.95	3.702 (3)	136
Symmetry codes: (i) $[x-{\script{1\over 2}}, -y+{\script{3\over 2}}, -z]$ ; (ii) $[x+{\script{1\over 2}}, -y+{\script{3\over 2}}, -z]$ ; (iii) $[-x+1, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ . Cg1 is the centroid of the C6–C11 ring.

Data collection: APEX2 (Bruker, 2007 ); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ); molecular graphics: ORTEP-3 (Farrugia, 1997 ) and DIAMOND (Brandenburg, 2006 ); software used to prepare material for publication: publCIF (Westrip, 2010 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810043187/hg2732sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810043187/hg2732Isup2.hkl

checkCIF report

Comment top

N-Acyliminium ions are very important in organic synthesis since they are reactive intermediates involved in the synthesis of many compounds with interesting biological properties (Vieira et al., 2008). Nucleophilic additions to N-acyliminium ions constitute an important method to provide α-functionalized amino compounds and for the preparation of alkaloids (Huang, 2006) and many other biologically active nitrogen heterocycles, such as ethosuximide used in the treatment of epilepsy (Russo et al., 2010). As part of our on-going research interest in bioactive compounds (Caracelli et al., 2010) the title compound, (I), was synthesized and its crystal structure determined as described herein.

The molecular structure of (I), Fig. 1, shows the pyrrolidine-2,5-dione ring [r.m.s. deviation of the N1,C1–C4 atoms = 0.105 Å] to adopt a twisted conformation with the C2 and C3 atoms being displaced by 0.089 (2) and -0.087 (2) Å, respectively, out of the plane. The ring-puckering parameters are q₂ = 0.149 (2) Å, and φ₂ = 87.4 (8) ° (Cremer & Pople, 1975; Iulek & Zukerman-Schpector, 1997). The O1 and O6 atoms lie -0.178 (2) and 0.139 (2) Å out of the plane through the pyrrolidine ring, and the benzene ring is orientated to be normal to the ring as seen in the dihedral angle formed between their least-squares planes [76.57 (14) °]. The acetyl groups lie on opposite sides of the pyrrolidine plane. To a first approximation, the structure of (I) resembles that reported recently for the N-(m-tolyl) analogue (Naz et al., 2009).

In the crystal packing, molecules are connected via C—H···O and C—H···π interactions, Fig. 2 and Table 1.

Related literature top

For the use of N-acyliminium in organic synthesis, see: Vieira et al. (2008); Huang (2006); Russo et al. (2010). For background to the synthesis, see: Caracelli et al. (2010). For a related structure, see: Naz et al. (2009). For conformational analysis, see: Cremer & Pople (1975); Iulek & Zukerman-Schpector (1997).

Experimental top

A mixture of L-tartaric acid (15.0 g, 100 mmol) and acetylchloride (70 ml, 1.0 mol) was stirred under reflux for 24 h under nitrogen atmosphere, during which the solution became homogeneous. Excess acetyl chloride was removed by distillation at 1 atm and trace amounts were removed under vacuum. The resulting crude anhydride was dissolved in dry THF (120 ml) and benzylamine (10.7 g,100 mmol) was slowly added. The solution was stirred for 4 h, and then concentrated in vacuum. The residue was then refluxed with acetyl chloride (70 ml, 1.0 mol) for another 5 h. After concentration of the reaction mixture under vacuum, the residue was purified by column chromatography (n-hexane/ethyl acetate, 2:1) to give the title compound (23.8 g, 78%) as a white solid. Single crystals of (I) were obtained by slow evaporation from its ethyl acetate-hexane solution.

Structure description top

In the crystal packing, molecules are connected via C—H···O and C—H···π interactions, Fig. 2 and Table 1.

For the use of N-acyliminium in organic synthesis, see: Vieira et al. (2008); Huang (2006); Russo et al. (2010). For background to the synthesis, see: Caracelli et al. (2010). For a related structure, see: Naz et al. (2009). For conformational analysis, see: Cremer & Pople (1975); Iulek & Zukerman-Schpector (1997).

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top

	Fig. 1. Molecular structure of (I) showing atom labelling scheme and displacement ellipsoids at the 35% probability level.
	Fig. 2. Unit-cell contents shown in projection down the a axis in (I). The C—H···O and C—H···π contacts are shown as orange and purple dashed lines, respectively.

1-Benzyl-2,5-dioxopyrrolidine-3,4-diyl diacetate top

Crystal data top

C₁₅H₁₅NO₆	F(000) = 640
M_r = 305.28	D_x = 1.333 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 5560 reflections
a = 8.8498 (4) Å	θ = 2.9–26.4°
b = 9.8107 (4) Å	µ = 0.10 mm⁻¹
c = 17.5148 (6) Å	T = 290 K
V = 1520.68 (11) Å³	Block, colourless
Z = 4	0.28 × 0.23 × 0.06 mm

Data collection top

Bruker SMART APEXII diffractometer	1541 independent reflections
Radiation source: fine-focus sealed tube	1396 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.122
φ and ω scans	θ_max = 25.0°, θ_min = 3.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→10
T_min = 0.962, T_max = 0.991	k = −10→11
7672 measured reflections	l = −20→20

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.036	H-atom parameters constrained
wR(F²) = 0.085	w = 1/[σ²(F_o²) + (0.0293P)² + 0.1923P] where P = (F_o² + 2F_c²)/3
S = 1.07	(Δ/σ)_max = 0.001
1541 reflections	Δρ_max = 0.12 e Å⁻³
202 parameters	Δρ_min = −0.12 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.111 (10)

Crystal data top

C₁₅H₁₅NO₆	V = 1520.68 (11) Å³
M_r = 305.28	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 8.8498 (4) Å	µ = 0.10 mm⁻¹
b = 9.8107 (4) Å	T = 290 K
c = 17.5148 (6) Å	0.28 × 0.23 × 0.06 mm

Data collection top

Bruker SMART APEXII diffractometer	1541 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1396 reflections with I > 2σ(I)
T_min = 0.962, T_max = 0.991	R_int = 0.122
7672 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.036	0 restraints
wR(F²) = 0.085	H-atom parameters constrained
S = 1.07	Δρ_max = 0.12 e Å⁻³
1541 reflections	Δρ_min = −0.12 e Å⁻³
202 parameters

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.25814 (16)	0.67116 (18)	0.09591 (10)	0.0555 (5)
O2	0.42326 (15)	0.75768 (16)	−0.03939 (9)	0.0425 (4)
O3	0.57172 (17)	0.60872 (18)	0.02191 (10)	0.0505 (4)
O4	0.5859 (2)	1.03936 (19)	0.03516 (11)	0.0652 (6)
O5	0.3864 (3)	1.1015 (2)	0.10556 (14)	0.0772 (6)
O6	0.6412 (2)	0.93139 (18)	0.18931 (10)	0.0603 (5)
N1	0.44087 (19)	0.79166 (19)	0.15977 (11)	0.0418 (5)
C1	0.3594 (2)	0.7537 (2)	0.09654 (13)	0.0415 (5)
C2	0.4146 (2)	0.8367 (2)	0.02866 (13)	0.0400 (5)
H2	0.3419	0.9104	0.0199	0.048*
C3	0.5611 (2)	0.9008 (2)	0.05719 (14)	0.0448 (5)
H3	0.6453	0.8463	0.0374	0.054*
C4	0.5564 (2)	0.8820 (2)	0.14324 (14)	0.0437 (5)
C5	0.4073 (3)	0.7405 (3)	0.23638 (14)	0.0510 (6)
H5A	0.4951	0.7538	0.2687	0.061*
H5B	0.3875	0.6434	0.2336	0.061*
C6	0.2737 (3)	0.8104 (2)	0.27199 (13)	0.0482 (6)
C7	0.1408 (3)	0.7410 (3)	0.28440 (16)	0.0629 (7)
H7	0.1336	0.6495	0.2708	0.075*
C8	0.0181 (4)	0.8059 (4)	0.3169 (2)	0.0835 (10)
H8	−0.0709	0.7579	0.3254	0.100*
C9	0.0272 (5)	0.9408 (4)	0.3365 (2)	0.0896 (12)
H9	−0.0554	0.9845	0.3584	0.108*
C10	0.1573 (5)	1.0103 (4)	0.3238 (2)	0.0956 (12)
H10	0.1636	1.1019	0.3370	0.115*
C11	0.2808 (4)	0.9457 (3)	0.2914 (2)	0.0748 (9)
H11	0.3693	0.9944	0.2828	0.090*
C12	0.5071 (2)	0.6412 (2)	−0.03556 (14)	0.0425 (5)
C13	0.5040 (3)	0.5656 (3)	−0.10878 (16)	0.0586 (7)
H13A	0.5864	0.5020	−0.1102	0.088*
H13B	0.5135	0.6287	−0.1504	0.088*
H13C	0.4102	0.5172	−0.1132	0.088*
C14	0.4873 (5)	1.1318 (3)	0.06372 (18)	0.0722 (9)
C15	0.5247 (7)	1.2725 (3)	0.0367 (3)	0.1274 (19)
H15A	0.4450	1.3338	0.0509	0.191*
H15B	0.5355	1.2721	−0.0178	0.191*
H15C	0.6177	1.3018	0.0597	0.191*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0492 (8)	0.0622 (11)	0.0550 (11)	−0.0163 (8)	0.0025 (7)	0.0034 (9)
O2	0.0459 (7)	0.0426 (8)	0.0388 (8)	0.0016 (7)	−0.0020 (6)	−0.0024 (7)
O3	0.0532 (8)	0.0470 (9)	0.0514 (10)	0.0047 (8)	−0.0038 (8)	0.0011 (8)
O4	0.0894 (13)	0.0503 (10)	0.0558 (11)	−0.0256 (10)	0.0064 (10)	0.0006 (9)
O5	0.1066 (15)	0.0511 (11)	0.0739 (14)	0.0153 (12)	0.0061 (13)	−0.0027 (11)
O6	0.0602 (10)	0.0644 (11)	0.0562 (11)	−0.0106 (9)	−0.0110 (8)	−0.0119 (10)
N1	0.0427 (9)	0.0433 (10)	0.0395 (10)	0.0004 (8)	−0.0002 (7)	−0.0005 (9)
C1	0.0390 (10)	0.0409 (11)	0.0445 (12)	0.0007 (10)	0.0029 (9)	−0.0015 (11)
C2	0.0417 (10)	0.0394 (11)	0.0390 (11)	0.0005 (9)	0.0015 (9)	−0.0021 (10)
C3	0.0473 (11)	0.0414 (11)	0.0457 (13)	−0.0088 (10)	0.0046 (10)	−0.0064 (11)
C4	0.0438 (11)	0.0408 (12)	0.0465 (12)	0.0000 (11)	−0.0002 (10)	−0.0050 (10)
C5	0.0585 (12)	0.0517 (13)	0.0428 (12)	0.0063 (12)	0.0029 (10)	0.0077 (12)
C6	0.0628 (13)	0.0482 (12)	0.0337 (12)	0.0064 (12)	0.0026 (10)	0.0025 (11)
C7	0.0716 (15)	0.0587 (15)	0.0584 (17)	0.0038 (15)	0.0144 (13)	0.0088 (15)
C8	0.0765 (18)	0.101 (3)	0.073 (2)	0.016 (2)	0.0284 (16)	0.018 (2)
C9	0.104 (3)	0.100 (3)	0.0645 (19)	0.048 (2)	0.0299 (18)	0.007 (2)
C10	0.134 (3)	0.071 (2)	0.082 (2)	0.024 (2)	0.022 (2)	−0.019 (2)
C11	0.0864 (19)	0.0607 (16)	0.077 (2)	0.0022 (17)	0.0113 (17)	−0.0182 (17)
C12	0.0421 (10)	0.0384 (12)	0.0469 (13)	−0.0025 (10)	0.0043 (10)	−0.0014 (10)
C13	0.0644 (14)	0.0558 (15)	0.0557 (15)	−0.0018 (14)	0.0033 (12)	−0.0154 (14)
C14	0.123 (3)	0.0413 (14)	0.0525 (16)	−0.0093 (17)	−0.0130 (19)	0.0001 (14)
C15	0.246 (6)	0.0468 (18)	0.090 (3)	−0.032 (3)	−0.023 (3)	0.0162 (19)

Geometric parameters (Å, º) top

O1—C1	1.208 (2)	C6—C11	1.372 (4)
O2—C12	1.365 (3)	C6—C7	1.376 (4)
O2—C2	1.424 (3)	C7—C8	1.382 (4)
O3—C12	1.201 (3)	C7—H7	0.9300
O4—C14	1.354 (4)	C8—C9	1.370 (5)
O4—C3	1.430 (3)	C8—H8	0.9300
O5—C14	1.193 (4)	C9—C10	1.356 (6)
O6—C4	1.204 (3)	C9—H9	0.9300
N1—C1	1.373 (3)	C10—C11	1.385 (5)
N1—C4	1.384 (3)	C10—H10	0.9300
N1—C5	1.463 (3)	C11—H11	0.9300
C1—C2	1.522 (3)	C12—C13	1.481 (3)
C2—C3	1.525 (3)	C13—H13A	0.9600
C2—H2	0.9800	C13—H13B	0.9600
C3—C4	1.519 (3)	C13—H13C	0.9600
C3—H3	0.9800	C14—C15	1.496 (4)
C5—C6	1.502 (3)	C15—H15A	0.9600
C5—H5A	0.9700	C15—H15B	0.9600
C5—H5B	0.9700	C15—H15C	0.9600

C12—O2—C2	116.37 (16)	C6—C7—H7	119.7
C14—O4—C3	116.0 (2)	C8—C7—H7	119.7
C1—N1—C4	113.15 (19)	C9—C8—C7	120.2 (4)
C1—N1—C5	122.70 (18)	C9—C8—H8	119.9
C4—N1—C5	124.15 (19)	C7—C8—H8	119.9
O1—C1—N1	125.4 (2)	C10—C9—C8	119.6 (3)
O1—C1—C2	126.2 (2)	C10—C9—H9	120.2
N1—C1—C2	108.44 (17)	C8—C9—H9	120.2
O2—C2—C1	112.34 (17)	C9—C10—C11	120.5 (3)
O2—C2—C3	116.94 (17)	C9—C10—H10	119.8
C1—C2—C3	103.76 (18)	C11—C10—H10	119.8
O2—C2—H2	107.8	C6—C11—C10	120.5 (3)
C1—C2—H2	107.8	C6—C11—H11	119.7
C3—C2—H2	107.8	C10—C11—H11	119.7
O4—C3—C4	112.8 (2)	O3—C12—O2	121.5 (2)
O4—C3—C2	115.7 (2)	O3—C12—C13	127.0 (2)
C4—C3—C2	104.60 (18)	O2—C12—C13	111.5 (2)
O4—C3—H3	107.8	C12—C13—H13A	109.5
C4—C3—H3	107.8	C12—C13—H13B	109.5
C2—C3—H3	107.8	H13A—C13—H13B	109.5
O6—C4—N1	125.3 (2)	C12—C13—H13C	109.5
O6—C4—C3	126.8 (2)	H13A—C13—H13C	109.5
N1—C4—C3	107.78 (18)	H13B—C13—H13C	109.5
N1—C5—C6	112.58 (19)	O5—C14—O4	122.9 (3)
N1—C5—H5A	109.1	O5—C14—C15	126.1 (4)
C6—C5—H5A	109.1	O4—C14—C15	111.0 (4)
N1—C5—H5B	109.1	C14—C15—H15A	109.5
C6—C5—H5B	109.1	C14—C15—H15B	109.5
H5A—C5—H5B	107.8	H15A—C15—H15B	109.5
C11—C6—C7	118.6 (3)	C14—C15—H15C	109.5
C11—C6—C5	120.5 (3)	H15A—C15—H15C	109.5
C7—C6—C5	120.8 (2)	H15B—C15—H15C	109.5
C6—C7—C8	120.6 (3)

C4—N1—C1—O1	176.2 (2)	O4—C3—C4—O6	−44.1 (3)
C5—N1—C1—O1	−3.7 (3)	C2—C3—C4—O6	−170.7 (2)
C4—N1—C1—C2	−5.8 (2)	O4—C3—C4—N1	138.79 (19)
C5—N1—C1—C2	174.33 (19)	C2—C3—C4—N1	12.2 (2)
C12—O2—C2—C1	−54.5 (2)	C1—N1—C5—C6	−77.9 (3)
C12—O2—C2—C3	65.3 (2)	C4—N1—C5—C6	102.2 (2)
O1—C1—C2—O2	−41.8 (3)	N1—C5—C6—C11	−67.2 (3)
N1—C1—C2—O2	140.22 (17)	N1—C5—C6—C7	111.6 (3)
O1—C1—C2—C3	−169.0 (2)	C11—C6—C7—C8	−1.0 (5)
N1—C1—C2—C3	13.0 (2)	C5—C6—C7—C8	−179.7 (3)
C14—O4—C3—C4	−55.3 (3)	C6—C7—C8—C9	0.6 (5)
C14—O4—C3—C2	65.1 (3)	C7—C8—C9—C10	0.0 (6)
O2—C2—C3—O4	96.2 (2)	C8—C9—C10—C11	−0.2 (6)
C1—C2—C3—O4	−139.5 (2)	C7—C6—C11—C10	0.9 (5)
O2—C2—C3—C4	−139.1 (2)	C5—C6—C11—C10	179.6 (3)
C1—C2—C3—C4	−14.8 (2)	C9—C10—C11—C6	−0.3 (6)
C1—N1—C4—O6	178.6 (2)	C2—O2—C12—O3	−1.1 (3)
C5—N1—C4—O6	−1.5 (3)	C2—O2—C12—C13	178.27 (18)
C1—N1—C4—C3	−4.2 (2)	C3—O4—C14—O5	0.9 (4)
C5—N1—C4—C3	175.7 (2)	C3—O4—C14—C15	−179.9 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O3ⁱ	0.98	2.51	3.206 (2)	128
C3—H3···O1ⁱⁱ	0.98	2.55	3.276 (3)	131
C5—H5b···O6ⁱⁱⁱ	0.97	2.49	3.328 (3)	144
C13—H13b···Cg1ⁱⁱ	0.96	2.95	3.702 (3)	136

Symmetry codes: (i) x−1/2, −y+3/2, −z; (ii) x+1/2, −y+3/2, −z; (iii) −x+1, y−1/2, −z+1/2.

Experimental details

Crystal data
Chemical formula	C₁₅H₁₅NO₆
M_r	305.28
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	290
a, b, c (Å)	8.8498 (4), 9.8107 (4), 17.5148 (6)
V (Å³)	1520.68 (11)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.28 × 0.23 × 0.06

Data collection
Diffractometer	Bruker SMART APEXII
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.962, 0.991
No. of measured, independent and observed [I > 2σ(I)] reflections	7672, 1541, 1396
R_int	0.122
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.036, 0.085, 1.07
No. of reflections	1541
No. of parameters	202
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.12, −0.12

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O3ⁱ	0.98	2.51	3.206 (2)	128
C3—H3···O1ⁱⁱ	0.98	2.55	3.276 (3)	131
C5—H5b···O6ⁱⁱⁱ	0.97	2.49	3.328 (3)	144
C13—H13b···Cg1ⁱⁱ	0.96	2.95	3.702 (3)	136

Symmetry codes: (i) x−1/2, −y+3/2, −z; (ii) x+1/2, −y+3/2, −z; (iii) −x+1, y−1/2, −z+1/2.

Acknowledgements

We thank FAPESP (grant No. 07/59404–2 to HAS), CNPq (grant No. 300613/2007 to HAS) and CAPES (Rede Nanobiotec-Brasil grant No. 808/2009 to IC) for financial support.

References

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