Perillartine

Yuan, X.-Y.; Zhang, M.; Ng, S.W.

doi:10.1107/S1600536809031225

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 65| Part 9| September 2009| Page o2149

doi:10.1107/S1600536809031225

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Perillartine

Xian-You Yuan,^a Min Zhang ^a and Seik Weng Ng ^b ^*

^aDepartment of Biology and Chemistry, Hunan University of Science and Engineering, Yongzhou, Hunan 425100, People's Republic of China, and ^bDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
^*Correspondence e-mail: seikweng@um.edu.my

(Received 6 August 2009; accepted 6 August 2009; online 15 August 2009)

The chiral title compound [systematic name: 4-(1-methylvinyl)cyclohexene-1-carbaldehyde oxime], C₁₀H₁₅NO, crystallizes with two molecules in the asymmetric unit, one of which shows disorder of its propenyl substituent over two sets of sites in a 50:50 ratio. In both molecules, the six-membered carbaldehyde oxime ring adopts an approximate envelope conformation in which the C atom bearing the propenyl substituent represents the flap position. In both molecules, the plane passing through the propenyl substituent is nearly perpendicular to the mean plane of the six-membered ring [dihedral angles = 84.6 (6) and 87.4 (3)°]. In the crystal, the two independent molecules are linked by a pair O—H⋯N hydrogen bonds across a pseudo-inversion centre, generating a dimer. The unit cell of the known racemate of the title compound is similar to the cell found here, but with space group P $[\overline{1}]$ .

Related literature

Perillartine or perillartin [(S)-4-(prop-1-en-2-yl)cyclohex-1-ene carbaldehyde oxime], the oxime of perillaldehyde, is 2000 times sweeter than sucrose; see the handbook of artificial sweeteners by O'Brien Nabors & Gelardi (2001 ). For the crystal structure of the racemic compound, see: Hooft et al. (1990 ).

Experimental

Crystal data

C₁₀H₁₅NO
M_r = 165.23
Triclinic, P 1
a = 7.2679 (6) Å
b = 8.1702 (7) Å
c = 8.9426 (8) Å
α = 105.150 (1)°
β = 95.658 (1)°
γ = 104.602 (1)°
V = 488.25 (7) Å³
Z = 2
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 293 K
0.48 × 0.42 × 0.22 mm

Data collection

Bruker SMART diffractometer
Absorption correction: none
4074 measured reflections
2078 independent reflections
1457 reflections with I > 2σ(I)
R_int = 0.010

Refinement

R[F² > 2σ(F²)] = 0.043
wR(F²) = 0.139
S = 1.07
2078 reflections
234 parameters
21 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.15 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
O1—H1⋯N2	0.85 (4)	2.00 (2)	2.831 (4)	164 (5)
O2—H2⋯N1	0.85 (4)	2.04 (2)	2.811 (4)	150 (4)

Data collection: SMART (Bruker, 1997 ); cell refinement: SAINT (Bruker, 2003 ); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001 ); software used to prepare material for publication: publCIF (Westrip, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809031225/hb5034sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809031225/hb5034Isup2.hkl

checkCIF report

Related literature top

Perillartine or perillartin [(S)-4-(prop-1-en-2-yl)cyclohex-1-ene carbaldehyde oxime], the oxime of perillaldehyde, is 2000 times sweeter than sucrose; see the handbook of artificial sweeteners by O'Brien Nabors & Gelardi (2001). For the crystal structure of the racemic compound, see: Hooft et al. (1990).

Experimental top

Hydroxylamine hydrochloride (3.15 g, 0.045 mol) in water (50 ml) was treated with sodium carbonate (2.12 g, 0.02 mol). To this solution was added perillaldehyde (4.50 g, 0.03 mol). The mixture was kept at 318 K for 2 h. The solution was cooled and the solid that formed was heated in water for another 2 h. This was repeated a second time. The product was recrystallized from ethyl acetate to yield colourless blocks of (I) (yield 5.5 g, 80%); m.p. 374–375 K.

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2009).

Figures top

Fig. 1. The molecular structure of (I) at the 50% probability level; hydrogen atoms are drawn as spheres of arbitrary radius. The disorder is not shown.

4-(1-Methylvinyl)cyclohexene-1-carbaldehyde oxime top

Crystal data top

C₁₀H₁₅NO	Z = 2
M_r = 165.23	F(000) = 180
Triclinic, P1	D_x = 1.124 Mg m⁻³
Hall symbol: P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.2679 (6) Å	Cell parameters from 1889 reflections
b = 8.1702 (7) Å	θ = 2.4–26.9°
c = 8.9426 (8) Å	µ = 0.07 mm⁻¹
α = 105.150 (1)°	T = 293 K
β = 95.658 (1)°	Block, colorless
γ = 104.602 (1)°	0.48 × 0.42 × 0.22 mm
V = 488.25 (7) Å³

Data collection top

Bruker SMART diffractometer	1457 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.014
Graphite monochromator	θ_max = 27.1°, θ_min = 2.4°
ϕ and ω scans	h = −9→9
4074 measured reflections	k = −10→10
2078 independent reflections	l = −11→11

Refinement top

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)] = 0.043	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.139	H atoms treated by a mixture of independent and constrained refinement
S = 1.07	w = 1/[σ²(F_o²) + (0.0793P)² + 0.0172P] where P = (F_o² + 2F_c²)/3
2078 reflections	(Δ/σ)_max < 0.001
234 parameters	Δρ_max = 0.15 e Å⁻³
21 restraints	Δρ_min = −0.12 e Å⁻³

Crystal data top

C₁₀H₁₅NO	γ = 104.602 (1)°
M_r = 165.23	V = 488.25 (7) Å³
Triclinic, P1	Z = 2
a = 7.2679 (6) Å	Mo Kα radiation
b = 8.1702 (7) Å	µ = 0.07 mm⁻¹
c = 8.9426 (8) Å	T = 293 K
α = 105.150 (1)°	0.48 × 0.42 × 0.22 mm
β = 95.658 (1)°

Data collection top

Bruker SMART diffractometer	1457 reflections with I > 2σ(I)
4074 measured reflections	R_int = 0.014
2078 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.043	21 restraints
wR(F²) = 0.139	H atoms treated by a mixture of independent and constrained refinement
S = 1.07	Δρ_max = 0.15 e Å⁻³
2078 reflections	Δρ_min = −0.12 e Å⁻³
234 parameters

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
O1	0.5000 (4)	0.5002 (4)	0.5001 (3)	0.0885 (8)
O2	0.7482 (4)	0.9157 (4)	0.6717 (4)	0.0922 (8)
N1	0.4289 (4)	0.6405 (4)	0.4831 (3)	0.0724 (8)
N2	0.8170 (4)	0.7770 (4)	0.6971 (3)	0.0727 (7)
C1	0.2564 (5)	0.5857 (4)	0.4097 (4)	0.0699 (8)
H1A	0.1932	0.4649	0.3775	0.084*
C2	0.1551 (5)	0.7069 (4)	0.3745 (4)	0.0657 (8)
C3	−0.0246 (5)	0.6464 (4)	0.2976 (4)	0.0758 (9)
H3	−0.0836	0.5251	0.2706	0.091*
C4	−0.1401 (5)	0.7574 (4)	0.2510 (4)	0.0776 (9)
H4A	−0.2386	0.7643	0.3161	0.093*
H4B	−0.2048	0.7010	0.1425	0.093*
C5	−0.0167 (5)	0.9448 (4)	0.2672 (4)	0.0760 (9)
H5	0.0572	0.9363	0.1809	0.091*
C6	0.1263 (6)	1.0142 (4)	0.4182 (6)	0.0973 (13)
H6A	0.0572	1.0176	0.5058	0.117*
H6B	0.2013	1.1345	0.4291	0.117*
C7	0.2618 (6)	0.9016 (5)	0.4248 (5)	0.0905 (12)
H7A	0.3552	0.9237	0.3567	0.109*
H7B	0.3320	0.9354	0.5314	0.109*
C8	−0.1413 (5)	1.0638 (4)	0.2484 (4)	0.0784 (10)	0.50
C9	−0.2394 (18)	1.127 (2)	0.3557 (11)	0.088 (3)	0.50
H9A	−0.3134	1.1999	0.3366	0.105*	0.50
H9B	−0.2342	1.0994	0.4501	0.105*	0.50
C10	−0.1478 (19)	1.1072 (18)	0.0954 (12)	0.093 (3)	0.50
H10A	−0.2124	1.0017	0.0107	0.139*	0.50
H10B	−0.0186	1.1541	0.0797	0.139*	0.50
H10C	−0.2167	1.1936	0.0979	0.139*	0.50
C8'	−0.1413 (5)	1.0638 (4)	0.2484 (4)	0.0784 (10)	0.50
C9'	−0.1960 (17)	1.0794 (19)	0.1074 (12)	0.088 (3)	0.50
H9'A	−0.2772	1.1487	0.0964	0.105*	0.50
H9'B	−0.1529	1.0210	0.0200	0.105*	0.50
C10'	−0.208 (2)	1.157 (2)	0.3937 (11)	0.093 (3)	0.50
H10D	−0.2765	1.2350	0.3683	0.139*	0.50
H10E	−0.0981	1.2236	0.4747	0.139*	0.50
H10F	−0.2922	1.0702	0.4303	0.139*	0.50
C11	0.9893 (5)	0.8319 (4)	0.7688 (4)	0.0733 (9)
H11	1.0553	0.9518	0.7953	0.088*
C12	1.0866 (5)	0.7107 (4)	0.8108 (4)	0.0644 (8)
C13	1.2696 (5)	0.7692 (4)	0.8782 (5)	0.0781 (10)
H13	1.3307	0.8898	0.9017	0.094*
C14	1.3864 (5)	0.6556 (4)	0.9198 (5)	0.0798 (10)
H14A	1.4061	0.6763	1.0328	0.096*
H14B	1.5121	0.6889	0.8899	0.096*
C15	1.2887 (4)	0.4597 (4)	0.8383 (4)	0.0632 (7)
H15	1.2949	0.4391	0.7262	0.076*
C16	1.0754 (4)	0.4179 (4)	0.8527 (5)	0.0746 (9)
H16A	1.0134	0.2921	0.8053	0.090*
H16B	1.0640	0.4475	0.9631	0.090*
C17	0.9742 (5)	0.5210 (4)	0.7724 (5)	0.0763 (10)
H17A	0.9523	0.4671	0.6594	0.092*
H17B	0.8492	0.5137	0.8041	0.092*
C18	1.3935 (4)	0.3442 (4)	0.8964 (4)	0.0666 (8)
C19	1.4889 (6)	0.2566 (5)	0.8038 (5)	0.0813 (9)
H19A	1.5548	0.1866	0.8401	0.098*
H19B	1.4904	0.2646	0.7021	0.098*
C20	1.3869 (7)	0.3355 (6)	1.0597 (5)	0.0934 (11)
H20A	1.4500	0.2509	1.0786	0.140*
H20B	1.2548	0.2998	1.0733	0.140*
H20C	1.4516	0.4500	1.1328	0.140*
H1	0.599 (5)	0.568 (5)	0.568 (5)	0.115 (18)*
H2	0.641 (4)	0.866 (5)	0.609 (5)	0.110 (17)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.096 (2)	0.0817 (17)	0.1005 (18)	0.0444 (17)	0.0085 (16)	0.0344 (14)
O2	0.095 (2)	0.0784 (16)	0.114 (2)	0.0444 (16)	0.0000 (17)	0.0349 (15)
N1	0.079 (2)	0.0743 (18)	0.0748 (16)	0.0356 (16)	0.0104 (15)	0.0285 (14)
N2	0.0716 (19)	0.0704 (17)	0.0855 (18)	0.0333 (15)	0.0092 (15)	0.0282 (14)
C1	0.078 (2)	0.0649 (19)	0.0689 (19)	0.0273 (18)	0.0089 (17)	0.0181 (15)
C2	0.068 (2)	0.0613 (18)	0.0666 (18)	0.0211 (15)	0.0059 (15)	0.0160 (14)
C3	0.071 (2)	0.0540 (18)	0.090 (2)	0.0132 (17)	−0.0072 (18)	0.0111 (16)
C4	0.065 (2)	0.0647 (19)	0.090 (2)	0.0149 (16)	−0.0079 (17)	0.0122 (17)
C5	0.0624 (19)	0.072 (2)	0.091 (2)	0.0177 (15)	0.0000 (16)	0.0272 (17)
C6	0.082 (2)	0.0569 (17)	0.134 (3)	0.0146 (16)	−0.035 (2)	0.0212 (19)
C7	0.071 (2)	0.068 (2)	0.119 (3)	0.0139 (18)	−0.021 (2)	0.024 (2)
C8	0.064 (2)	0.067 (2)	0.100 (3)	0.0135 (16)	−0.0078 (17)	0.0302 (18)
C9	0.097 (5)	0.108 (6)	0.076 (3)	0.048 (4)	0.020 (3)	0.040 (3)
C10	0.103 (5)	0.083 (4)	0.093 (4)	0.033 (4)	0.002 (3)	0.027 (3)
C8'	0.064 (2)	0.067 (2)	0.100 (3)	0.0135 (16)	−0.0078 (17)	0.0302 (18)
C9'	0.097 (5)	0.108 (6)	0.076 (3)	0.048 (4)	0.020 (3)	0.040 (3)
C10'	0.103 (5)	0.083 (4)	0.093 (4)	0.033 (4)	0.002 (3)	0.027 (3)
C11	0.075 (2)	0.0609 (19)	0.086 (2)	0.0230 (18)	0.0118 (18)	0.0229 (16)
C12	0.063 (2)	0.0578 (17)	0.0732 (18)	0.0205 (15)	0.0092 (15)	0.0195 (14)
C13	0.064 (2)	0.0537 (18)	0.107 (3)	0.0101 (16)	−0.0006 (18)	0.0200 (17)
C14	0.057 (2)	0.0608 (19)	0.112 (3)	0.0107 (16)	−0.0085 (18)	0.0231 (18)
C15	0.0576 (16)	0.0601 (16)	0.0705 (17)	0.0166 (13)	0.0037 (13)	0.0203 (13)
C16	0.0581 (18)	0.0659 (18)	0.100 (2)	0.0123 (15)	0.0015 (16)	0.0355 (18)
C17	0.056 (2)	0.066 (2)	0.105 (3)	0.0164 (16)	−0.0043 (17)	0.0292 (18)
C18	0.0528 (17)	0.0590 (18)	0.082 (2)	0.0124 (15)	−0.0022 (14)	0.0187 (15)
C19	0.080 (2)	0.0733 (19)	0.092 (2)	0.0299 (18)	0.0063 (18)	0.0227 (17)
C20	0.094 (3)	0.107 (3)	0.095 (2)	0.041 (2)	0.010 (2)	0.047 (2)

Geometric parameters (Å, º) top

O1—N1	1.407 (3)	C9'—H9'A	0.9300
O1—H1	0.85 (4)	C9'—H9'B	0.9300
O2—N2	1.408 (3)	C10'—H10D	0.9600
O2—H2	0.85 (4)	C10'—H10E	0.9600
N1—C1	1.266 (4)	C10'—H10F	0.9600
N2—C11	1.261 (5)	C11—C12	1.455 (4)
C1—C2	1.451 (4)	C11—H11	0.9300
C1—H1A	0.9300	C12—C13	1.316 (5)
C2—C3	1.320 (5)	C12—C17	1.489 (5)
C2—C7	1.506 (5)	C13—C14	1.495 (4)
C3—C4	1.487 (4)	C13—H13	0.9300
C3—H3	0.9300	C14—C15	1.520 (4)
C4—C5	1.529 (5)	C14—H14A	0.9700
C4—H4A	0.9700	C14—H14B	0.9700
C4—H4B	0.9700	C15—C18	1.511 (4)
C5—C6	1.500 (5)	C15—C16	1.527 (4)
C5—C8	1.514 (4)	C15—H15	0.9800
C5—H5	0.9800	C16—C17	1.514 (4)
C6—C7	1.515 (5)	C16—H16A	0.9700
C6—H6A	0.9700	C16—H16B	0.9700
C6—H6B	0.9700	C17—H17A	0.9700
C7—H7A	0.9700	C17—H17B	0.9700
C7—H7B	0.9700	C18—C19	1.316 (5)
C8—C9	1.327 (8)	C18—C20	1.485 (5)
C8—C10	1.500 (8)	C19—H19A	0.9300
C9—H9A	0.9300	C19—H19B	0.9300
C9—H9B	0.9300	C20—H20A	0.9600
C10—H10A	0.9600	C20—H20B	0.9600
C10—H10B	0.9600	C20—H20C	0.9600
C10—H10C	0.9600

N1—O1—H1	94 (3)	H10E—C10'—H10F	109.5
N2—O2—H2	106 (3)	N2—C11—C12	121.0 (3)
C1—N1—O1	111.9 (3)	N2—C11—H11	119.5
C11—N2—O2	112.1 (3)	C12—C11—H11	119.5
N1—C1—C2	121.6 (3)	C13—C12—C11	120.0 (3)
N1—C1—H1A	119.2	C13—C12—C17	121.9 (3)
C2—C1—H1A	119.2	C11—C12—C17	118.0 (3)
C3—C2—C1	120.4 (3)	C12—C13—C14	124.6 (3)
C3—C2—C7	121.3 (3)	C12—C13—H13	117.7
C1—C2—C7	118.3 (3)	C14—C13—H13	117.7
C2—C3—C4	125.1 (3)	C13—C14—C15	112.1 (3)
C2—C3—H3	117.5	C13—C14—H14A	109.2
C4—C3—H3	117.5	C15—C14—H14A	109.2
C3—C4—C5	112.7 (3)	C13—C14—H14B	109.2
C3—C4—H4A	109.1	C15—C14—H14B	109.2
C5—C4—H4A	109.1	H14A—C14—H14B	107.9
C3—C4—H4B	109.1	C18—C15—C14	112.0 (2)
C5—C4—H4B	109.1	C18—C15—C16	114.2 (2)
H4A—C4—H4B	107.8	C14—C15—C16	108.9 (3)
C6—C5—C8	114.0 (3)	C18—C15—H15	107.1
C6—C5—C4	109.6 (3)	C14—C15—H15	107.1
C8—C5—C4	111.3 (3)	C16—C15—H15	107.1
C6—C5—H5	107.2	C17—C16—C15	111.1 (2)
C8—C5—H5	107.2	C17—C16—H16A	109.4
C4—C5—H5	107.2	C15—C16—H16A	109.4
C5—C6—C7	112.3 (3)	C17—C16—H16B	109.4
C5—C6—H6A	109.2	C15—C16—H16B	109.4
C7—C6—H6A	109.2	H16A—C16—H16B	108.0
C5—C6—H6B	109.2	C12—C17—C16	112.7 (3)
C7—C6—H6B	109.2	C12—C17—H17A	109.0
H6A—C6—H6B	107.9	C16—C17—H17A	109.0
C2—C7—C6	111.9 (3)	C12—C17—H17B	109.0
C2—C7—H7A	109.2	C16—C17—H17B	109.0
C6—C7—H7A	109.2	H17A—C17—H17B	107.8
C2—C7—H7B	109.2	C19—C18—C20	122.0 (3)
C6—C7—H7B	109.2	C19—C18—C15	120.0 (3)
H7A—C7—H7B	107.9	C20—C18—C15	118.0 (3)
C9—C8—C10	120.8 (8)	C18—C19—H19A	120.0
C9—C8—C5	124.4 (6)	C18—C19—H19B	120.0
C10—C8—C5	114.7 (6)	H19A—C19—H19B	120.0
C8—C9—H9A	120.0	C18—C20—H20A	109.5
C8—C9—H9B	120.0	C18—C20—H20B	109.5
H9A—C9—H9B	120.0	H20A—C20—H20B	109.5
H9'A—C9'—H9'B	120.0	C18—C20—H20C	109.5
H10D—C10'—H10E	109.5	H20A—C20—H20C	109.5
H10D—C10'—H10F	109.5	H20B—C20—H20C	109.5

O1—N1—C1—C2	−178.2 (3)	O2—N2—C11—C12	178.3 (3)
N1—C1—C2—C3	179.9 (3)	N2—C11—C12—C13	176.4 (3)
N1—C1—C2—C7	1.2 (5)	N2—C11—C12—C17	−2.5 (5)
C1—C2—C3—C4	−178.0 (3)	C11—C12—C13—C14	−177.1 (3)
C7—C2—C3—C4	0.7 (6)	C17—C12—C13—C14	1.7 (6)
C2—C3—C4—C5	13.1 (5)	C12—C13—C14—C15	15.1 (6)
C3—C4—C5—C6	−42.4 (4)	C13—C14—C15—C18	−172.6 (3)
C3—C4—C5—C8	−169.4 (3)	C13—C14—C15—C16	−45.3 (4)
C8—C5—C6—C7	−174.0 (4)	C18—C15—C16—C17	−172.3 (3)
C4—C5—C6—C7	60.5 (5)	C14—C15—C16—C17	61.8 (4)
C3—C2—C7—C6	15.8 (5)	C13—C12—C17—C16	13.8 (5)
C1—C2—C7—C6	−165.5 (3)	C11—C12—C17—C16	−167.3 (3)
C5—C6—C7—C2	−46.7 (5)	C15—C16—C17—C12	−45.5 (4)
C6—C5—C8—C9	−51.0 (9)	C14—C15—C18—C19	−109.8 (4)
C4—C5—C8—C9	73.5 (8)	C16—C15—C18—C19	125.9 (3)
C6—C5—C8—C10	129.0 (7)	C14—C15—C18—C20	69.4 (4)
C4—C5—C8—C10	−106.4 (7)	C16—C15—C18—C20	−54.9 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N2	0.85 (4)	2.00 (2)	2.831 (4)	164 (5)
O2—H2···N1	0.85 (4)	2.04 (2)	2.811 (4)	150 (4)

Experimental details

Crystal data
Chemical formula	C₁₀H₁₅NO
M_r	165.23
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	7.2679 (6), 8.1702 (7), 8.9426 (8)
α, β, γ (°)	105.150 (1), 95.658 (1), 104.602 (1)
V (Å³)	488.25 (7)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.07
Crystal size (mm)	0.48 × 0.42 × 0.22

Data collection
Diffractometer	Bruker SMART diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	4074, 2078, 1457
R_int	0.014
(sin θ/λ)_max (Å⁻¹)	0.640

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.043, 0.139, 1.07
No. of reflections	2078
No. of parameters	234
No. of restraints	21
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.15, −0.12

Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 2003), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001), publCIF (Westrip, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N2	0.85 (4)	2.00 (2)	2.831 (4)	164 (5)
O2—H2···N1	0.85 (4)	2.04 (2)	2.811 (4)	150 (4)

Acknowledgements

We thank the Key Subject Construction Project of Hunan Province (No. 2006–180), the Key Scientific Research Project of Hunan Provincial Education Department (No. 08 A023), the NSF of Hunan Province (No. 09 J J3028) and the University of Malaya for supporting this study.

References

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