Crystal structure of obscurine: a natural product isolated from the stem bark of B. obscura

Lenta, B.N.; Chouna, R.J.; Neumann, B.; Stammler, H.-G.; Sewald, N.

doi:10.1107/S2056989015010567

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 71| Part 7| July 2015| Pages o457-o458

doi:10.1107/S2056989015010567

Open

access

Crystal structure of obscurine: a natural product isolated from the stem bark of B. obscura

Bruno N. Lenta,^a ^* Rodolphe J. Chouna,^b Beate Neumann,^c Hans-Georg Stammler ^c and Norbert Sewald ^c

^aDepartment of Chemistry, Higher Teacher Training College, University of Yaoundé 1, PO Box 47, Yaoundé, Cameroon, ^bDepartment of Chemistry, University of Dschang, PO Box 371, Dschang, Cameroon, and ^cDepartment of Chemistry, University of Bielefeld, PO Box 100131, 33501 Bielefeld, Germany
^*Correspondence e-mail: lentabruno@yahoo.fr

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 21 April 2015; accepted 1 June 2015; online 10 June 2015)

The title compound, C₂₄H₃₁NO₃ {systematic name: (E)-3-[(1R*,2S*,4aS*,8aR*)-2-(benzo[d][1,3]dioxol-5-yl)-1,2,4a,5,6,7,8,8a-octahydronaphthalen-1-yl]-N-isobutylacrylamide}, is a natural product isolated from the stem bark of B. obscura. It is composed of an octahydronaphthalene ring system substituted with an essentially planar benzodioxole ring system [r.m.s. deviation = 0.012 Å] and an extended isobutylacrylamide group. In the crystal, molecules are linked by N—H⋯O hydrogen bonds, forming chains propagating along [100]. The chains are linked by pairs of C—H⋯O hydrogen bonds, involving inversion-related benzodioxole ring systems, forming ribbons lying parallel to (010). There are also C—H⋯π interactions present within the ribbons.

Keywords: crystal structure; obscurine; octahydronaphthalene; benzodioxole; isobutylacrylamide; N—H⋯O hydrogen bonds.

CCDC reference: 1404418

1. Related literature

For background to the Beilschmiedia genus, medicinal plants used in Cameroon, see: Chouna et al. (2009 , 2010 , 2011 ); Lenta et al. (2009 , 2011 ). For related structures, see: Balawsnt et al. (1975 ).

2. Experimental

2.1. Crystal data

C₂₄H₃₁NO₃
M_r = 381.50
Triclinic, $[P \overline 1]$
a = 5.14153 (16) Å
b = 9.7449 (3) Å
c = 20.4639 (5) Å
α = 98.839 (2)°
β = 90.946 (2)°
γ = 100.237 (3)°
V = 996.00 (5) Å³
Z = 2
Cu Kα radiation
μ = 0.66 mm⁻¹
T = 100 K
0.36 × 0.03 × 0.02 mm

2.2. Data collection

Agilent SuperNova, Dual, Cu at zero, Atlas diffractometer
Absorption correction: gaussian (CrysAlis PRO; Agilent, 2013 ) T_min = 0.798, T_max = 1.000
13324 measured reflections
3892 independent reflections
3425 reflections with I > 2σ(I)
R_int = 0.027

2.3. Refinement

R[F² > 2σ(F²)] = 0.035
wR(F²) = 0.091
S = 1.04
3892 reflections
377 parameters
All H-atom parameters refined
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

Cg2 is the centroid of the benzene ring C2–C7.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O3ⁱ	0.896 (16)	2.105 (16)	2.8938 (13)	146.3 (13)
C7—H7⋯O1ⁱⁱ	0.984 (16)	2.503 (16)	3.4264 (15)	156.3 (12)
C1—H1B⋯Cg2ⁱ	0.978 (16)	2.595 (15)	3.4578 (12)	147.4 (11)
Symmetry codes: (i) x-1, y, z; (ii) -x+1, -y+2, -z+1.

Data collection: CrysAlis PRO (Agilent, 2013); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008 ); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009 ) and PLATON (Spek, 2009 ).

Supporting information

CCDC reference: 1404418

Crystal structure: contains datablocks I, global. DOI: 10.1107/S2056989015010567/su5126sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2056989015010567/su5126Isup2.hkl

checkCIF report

Chemical context top

Plants of the Beilschmiedia genus have been the subject of research interest (Lenta et al., 2009, 2011; Chouna et al. 2011). Our interests involve the isolation of active constituents from the stem bark and leaves of B. obscura, a medicinal plant used in Cameroon. Herein, we report on the crystal structure of the title compound, a natural product isolated from the stem bark of B. obscura.

Isolation and crystallization top

The air-dried stem bark of B. obscura (400 g) was macerated with methanol at room temperature for 72 h. The methanol extract was concentrated under reduced pressure to give a residue of 16 g, which was selectively extracted with CH₂Cl₂ at room temperature to afford 4 g of the CH₂Cl₂ soluble residue. This extract was subjected to column chromatography (CC) over silica gel (0.023-0.20 mesh, Merck) and eluted with a gradient system of n-hexane/ CH₂Cl₂ and ( CH₂Cl₂/MeOH,) to afford obscurine (4.2 mg), the solid obtained was grounded and then recrystallised from a mixture of petroleum ether/dichlorometahne (1:1), yielding colourless needle-like crystals.

Refinement top

Crystal data, data collection and structure refinement details are summarized in Table 2. All of the H atoms were all located in difference Fourier maps and freely refined.

Related literature top

For background to the Beilschmiedia genus, medical plants used in Cameroon, see: Chouna et al. (2009, 2010, 2011); Lenta et al. (2009, 2011). For related structures, see: Balawsnt et al. (1975).

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: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009) and PLATON (Spek, 2009).

Figures top

	Fig. 1. A view of the molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 50% probabilityl evel.
	Fig. 2. A view along the b axis of the crystal packing of the title compound. The hydrogen bonds are shown as dashed lines (see Table 1 for details).

(E)-3-[(1R*,2S*,4aS*,8aR*)-2-(Benzo[d][1,3]dioxol-5-yl)-1,2,4a,5,6,7,8,8a-octahydronaphthalen-1-yl]-N-isobutylacrylamide top

Crystal data top

C₂₄H₃₁NO₃	Z = 2
M_r = 381.50	F(000) = 412
Triclinic, P1	D_x = 1.272 Mg m⁻³
a = 5.14153 (16) Å	Cu Kα radiation, λ = 1.5418 Å
b = 9.7449 (3) Å	Cell parameters from 7209 reflections
c = 20.4639 (5) Å	θ = 4.7–76.2°
α = 98.839 (2)°	µ = 0.66 mm⁻¹
β = 90.946 (2)°	T = 100 K
γ = 100.237 (3)°	Needle, clear colourless
V = 996.00 (5) Å³	0.36 × 0.03 × 0.02 mm

Data collection top

Agilent SuperNova, Dual, Cu at zero, Atlas diffractometer	3892 independent reflections
Radiation source: SuperNova (Cu) X-ray Source	3425 reflections with I > 2σ(I)
Mirror monochromator	R_int = 0.027
Detector resolution: 5.3114 pixels mm^-1	θ_max = 72.1°, θ_min = 4.4°
ω scans	h = −6→5
Absorption correction: gaussian (CrysAlis PRO; Agilent, 2013)	k = −11→12
T_min = 0.798, T_max = 1.000	l = −24→24
13324 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F² > 2σ(F²)] = 0.035	All H-atom parameters refined
wR(F²) = 0.091	w = 1/[σ²(F_o²) + (0.0424P)² + 0.3477P] where P = (F_o² + 2F_c²)/3
S = 1.04	(Δ/σ)_max = 0.001
3892 reflections	Δρ_max = 0.24 e Å⁻³
377 parameters	Δρ_min = −0.22 e Å⁻³
0 restraints

Crystal data top

C₂₄H₃₁NO₃	γ = 100.237 (3)°
M_r = 381.50	V = 996.00 (5) Å³
Triclinic, P1	Z = 2
a = 5.14153 (16) Å	Cu Kα radiation
b = 9.7449 (3) Å	µ = 0.66 mm⁻¹
c = 20.4639 (5) Å	T = 100 K
α = 98.839 (2)°	0.36 × 0.03 × 0.02 mm
β = 90.946 (2)°

Data collection top

Agilent SuperNova, Dual, Cu at zero, Atlas diffractometer	3892 independent reflections
Absorption correction: gaussian (CrysAlis PRO; Agilent, 2013)	3425 reflections with I > 2σ(I)
T_min = 0.798, T_max = 1.000	R_int = 0.027
13324 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.035	0 restraints
wR(F²) = 0.091	All H-atom parameters refined
S = 1.04	Δρ_max = 0.24 e Å⁻³
3892 reflections	Δρ_min = −0.22 e Å⁻³
377 parameters

Special details top

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

	x	y	z	U_iso*/U_eq
O3	0.99052 (16)	0.81354 (9)	0.86676 (4)	0.01947 (19)
O1	0.32116 (17)	0.81350 (9)	0.50886 (4)	0.0198 (2)
O2	0.26950 (17)	0.59230 (9)	0.54145 (4)	0.0211 (2)
N1	0.5440 (2)	0.79089 (11)	0.87047 (5)	0.0177 (2)
C7	0.7117 (2)	0.92262 (12)	0.58231 (6)	0.0155 (2)
C6	0.8900 (2)	0.89637 (12)	0.62993 (6)	0.0149 (2)
C14	0.9558 (2)	1.40385 (13)	0.81143 (6)	0.0189 (3)
C18	0.9906 (2)	1.00932 (12)	0.77808 (6)	0.0161 (2)
C19	0.7706 (2)	0.94294 (12)	0.80006 (6)	0.0172 (2)
C4	0.6528 (2)	0.65272 (13)	0.62212 (6)	0.0183 (2)
C16	1.2263 (2)	1.23586 (12)	0.74705 (6)	0.0152 (2)
C17	1.0186 (2)	1.10091 (12)	0.72506 (6)	0.0147 (2)
C2	0.5136 (2)	0.81316 (12)	0.55642 (6)	0.0154 (2)
C22	0.4536 (2)	0.77083 (13)	0.98764 (6)	0.0195 (3)
C8	1.1097 (2)	1.01511 (12)	0.66128 (6)	0.0150 (2)
C3	0.4823 (2)	0.68151 (12)	0.57583 (6)	0.0162 (2)
C5	0.8593 (2)	0.76299 (12)	0.64871 (6)	0.0174 (2)
C20	0.7803 (2)	0.84434 (12)	0.84886 (6)	0.0161 (2)
C21	0.5080 (2)	0.69546 (13)	0.91942 (6)	0.0182 (3)
C12	1.0346 (2)	1.41782 (12)	0.69190 (6)	0.0174 (2)
C13	1.0029 (3)	1.50233 (13)	0.75965 (6)	0.0192 (3)
C9	1.2170 (2)	1.11024 (13)	0.61238 (6)	0.0163 (2)
C11	1.2589 (2)	1.33271 (12)	0.69369 (6)	0.0153 (2)
C10	1.2835 (2)	1.24957 (13)	0.62661 (6)	0.0166 (2)
C23	0.3498 (3)	0.66495 (16)	1.03273 (7)	0.0293 (3)
C15	1.1801 (2)	1.32087 (13)	0.81431 (6)	0.0178 (2)
C1	0.1586 (2)	0.67567 (13)	0.49990 (6)	0.0186 (3)
C24	0.6991 (3)	0.87158 (15)	1.01892 (7)	0.0260 (3)
H16	1.402 (3)	1.2038 (15)	0.7515 (7)	0.016 (3)*
H11	1.426 (3)	1.4037 (15)	0.7059 (7)	0.015 (3)*
H17	0.844 (3)	1.1256 (15)	0.7138 (7)	0.015 (3)*
H21A	0.670 (3)	0.6545 (15)	0.9203 (7)	0.019 (4)*
H15A	1.345 (3)	1.3876 (15)	0.8301 (7)	0.017 (3)*
H4	0.633 (3)	0.5592 (17)	0.6353 (8)	0.026 (4)*
H9	1.238 (3)	1.0624 (15)	0.5679 (7)	0.018 (3)*
H5	0.986 (3)	0.7444 (16)	0.6806 (8)	0.023 (4)*
H12A	0.862 (3)	1.3498 (16)	0.6770 (7)	0.019 (4)*
H18	1.159 (3)	0.9934 (15)	0.7974 (7)	0.020 (4)*
H7	0.730 (3)	1.0156 (17)	0.5680 (7)	0.022 (4)*
H13A	1.169 (3)	1.5731 (16)	0.7739 (8)	0.023 (4)*
H14A	0.942 (3)	1.4596 (16)	0.8555 (8)	0.023 (4)*
H21B	0.354 (3)	0.6183 (16)	0.9026 (7)	0.022 (4)*
H1	0.399 (3)	0.8194 (16)	0.8567 (7)	0.022 (4)*
H1A	0.160 (3)	0.6301 (16)	0.4528 (8)	0.023 (4)*
H8	1.260 (3)	0.9720 (15)	0.6758 (7)	0.019 (4)*
H12B	1.068 (3)	1.4823 (16)	0.6573 (8)	0.021 (4)*
H14B	0.780 (3)	1.3357 (16)	0.7997 (8)	0.023 (4)*
H1B	−0.020 (3)	0.6828 (15)	0.5137 (7)	0.021 (4)*
H22	0.313 (3)	0.8255 (15)	0.9805 (7)	0.018 (3)*
H10	1.350 (3)	1.3042 (16)	0.5915 (8)	0.023 (4)*
H15B	1.146 (3)	1.2548 (17)	0.8489 (8)	0.025 (4)*
H13B	0.851 (3)	1.5540 (17)	0.7578 (8)	0.026 (4)*
H24A	0.841 (3)	0.8171 (19)	1.0287 (9)	0.036 (5)*
H24B	0.660 (3)	0.9237 (19)	1.0614 (9)	0.037 (5)*
H23A	0.483 (4)	0.609 (2)	1.0412 (9)	0.041 (5)*
H19	0.599 (3)	0.9535 (17)	0.7834 (8)	0.029 (4)*
H24C	0.775 (3)	0.9404 (19)	0.9890 (9)	0.036 (5)*
H23B	0.304 (4)	0.717 (2)	1.0772 (10)	0.043 (5)*
H23C	0.187 (4)	0.601 (2)	1.0128 (9)	0.043 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O3	0.0158 (4)	0.0234 (4)	0.0221 (4)	0.0068 (3)	0.0012 (3)	0.0090 (3)
O1	0.0191 (4)	0.0170 (4)	0.0230 (4)	0.0005 (3)	−0.0059 (3)	0.0060 (3)
O2	0.0198 (4)	0.0153 (4)	0.0277 (5)	−0.0001 (3)	−0.0058 (4)	0.0058 (3)
N1	0.0154 (5)	0.0214 (5)	0.0187 (5)	0.0052 (4)	0.0010 (4)	0.0087 (4)
C7	0.0162 (6)	0.0148 (5)	0.0173 (6)	0.0050 (4)	0.0025 (4)	0.0048 (4)
C6	0.0153 (5)	0.0152 (5)	0.0152 (5)	0.0049 (4)	0.0034 (4)	0.0031 (4)
C14	0.0176 (6)	0.0216 (6)	0.0169 (6)	0.0042 (5)	0.0017 (5)	0.0007 (5)
C18	0.0175 (6)	0.0160 (5)	0.0157 (6)	0.0054 (4)	−0.0008 (4)	0.0029 (4)
C19	0.0161 (6)	0.0199 (6)	0.0176 (6)	0.0060 (5)	0.0000 (4)	0.0059 (4)
C4	0.0207 (6)	0.0143 (6)	0.0218 (6)	0.0047 (5)	0.0027 (5)	0.0069 (4)
C16	0.0134 (5)	0.0160 (5)	0.0171 (6)	0.0040 (4)	−0.0006 (4)	0.0038 (4)
C17	0.0134 (5)	0.0166 (6)	0.0154 (6)	0.0048 (4)	−0.0001 (4)	0.0041 (4)
C2	0.0153 (5)	0.0175 (6)	0.0150 (5)	0.0059 (4)	0.0018 (4)	0.0043 (4)
C22	0.0195 (6)	0.0213 (6)	0.0200 (6)	0.0066 (5)	0.0031 (5)	0.0070 (5)
C8	0.0138 (5)	0.0154 (5)	0.0170 (6)	0.0049 (4)	0.0006 (4)	0.0038 (4)
C3	0.0147 (5)	0.0146 (5)	0.0188 (6)	0.0020 (4)	0.0022 (4)	0.0019 (4)
C5	0.0187 (6)	0.0172 (6)	0.0185 (6)	0.0067 (5)	0.0006 (5)	0.0056 (4)
C20	0.0175 (6)	0.0158 (5)	0.0156 (6)	0.0043 (4)	0.0004 (4)	0.0027 (4)
C21	0.0194 (6)	0.0169 (6)	0.0193 (6)	0.0027 (5)	0.0008 (5)	0.0068 (4)
C12	0.0185 (6)	0.0172 (6)	0.0181 (6)	0.0060 (5)	−0.0004 (5)	0.0045 (4)
C13	0.0198 (6)	0.0172 (6)	0.0218 (6)	0.0070 (5)	0.0003 (5)	0.0022 (5)
C9	0.0141 (6)	0.0189 (6)	0.0164 (6)	0.0039 (4)	0.0017 (4)	0.0032 (4)
C11	0.0135 (5)	0.0154 (5)	0.0171 (6)	0.0025 (4)	0.0006 (4)	0.0033 (4)
C10	0.0145 (6)	0.0187 (6)	0.0176 (6)	0.0031 (4)	0.0021 (4)	0.0061 (4)
C23	0.0335 (8)	0.0297 (7)	0.0245 (7)	−0.0006 (6)	0.0050 (6)	0.0109 (6)
C15	0.0181 (6)	0.0186 (6)	0.0164 (6)	0.0026 (5)	−0.0014 (5)	0.0026 (4)
C1	0.0181 (6)	0.0167 (6)	0.0203 (6)	0.0012 (5)	−0.0015 (5)	0.0037 (4)
C24	0.0296 (7)	0.0235 (7)	0.0233 (7)	0.0028 (6)	−0.0010 (6)	0.0018 (5)

Geometric parameters (Å, º) top

O3—C20	1.2363 (15)	C2—C3	1.3838 (16)
O1—C2	1.3772 (14)	C22—C21	1.5289 (17)
O1—C1	1.4341 (15)	C22—C23	1.5213 (18)
O2—C3	1.3772 (14)	C22—C24	1.5189 (18)
O2—C1	1.4386 (15)	C22—H22	0.991 (15)
N1—C20	1.3443 (16)	C8—C9	1.5120 (16)
N1—C21	1.4606 (15)	C8—H8	1.006 (15)
N1—H1	0.894 (16)	C5—H5	0.973 (16)
C7—C6	1.4093 (16)	C21—H21A	0.987 (16)
C7—C2	1.3705 (17)	C21—H21B	1.004 (16)
C7—H7	0.984 (16)	C12—C13	1.5269 (16)
C6—C8	1.5199 (16)	C12—C11	1.5384 (16)
C6—C5	1.3945 (16)	C12—H12A	1.020 (15)
C14—C13	1.5300 (17)	C12—H12B	1.014 (16)
C14—C15	1.5270 (17)	C13—H13A	1.007 (16)
C14—H14A	0.988 (16)	C13—H13B	1.003 (17)
C14—H14B	1.021 (16)	C9—C10	1.3250 (17)
C18—C19	1.3216 (18)	C9—H9	0.973 (15)
C18—C17	1.5007 (16)	C11—C10	1.5024 (16)
C18—H18	0.994 (15)	C11—H11	1.006 (15)
C19—C20	1.4944 (16)	C10—H10	0.988 (16)
C19—H19	0.970 (17)	C23—H23A	0.98 (2)
C4—C3	1.3732 (17)	C23—H23B	1.025 (19)
C4—C5	1.4050 (17)	C23—H23C	0.99 (2)
C4—H4	0.978 (16)	C15—H15A	0.990 (15)
C16—C17	1.5411 (16)	C15—H15B	1.025 (16)
C16—C11	1.5421 (16)	C1—H1A	0.997 (16)
C16—C15	1.5385 (16)	C1—H1B	0.978 (16)
C16—H16	1.016 (15)	C24—H24A	1.010 (18)
C17—C8	1.5640 (16)	C24—H24B	0.980 (18)
C17—H17	1.002 (14)	C24—H24C	1.010 (19)

C2—O1—C1	106.11 (9)	C4—C5—H5	118.5 (9)
C3—O2—C1	105.76 (9)	O3—C20—N1	123.23 (11)
C20—N1—C21	124.03 (10)	O3—C20—C19	121.94 (11)
C20—N1—H1	119.1 (10)	N1—C20—C19	114.83 (10)
C21—N1—H1	116.7 (10)	N1—C21—C22	112.10 (10)
C6—C7—H7	121.2 (9)	N1—C21—H21A	106.5 (9)
C2—C7—C6	117.32 (11)	N1—C21—H21B	106.8 (9)
C2—C7—H7	121.5 (9)	C22—C21—H21A	112.0 (9)
C7—C6—C8	119.41 (10)	C22—C21—H21B	110.2 (9)
C5—C6—C7	119.69 (11)	H21A—C21—H21B	109.0 (12)
C5—C6—C8	120.89 (10)	C13—C12—C11	111.67 (10)
C13—C14—H14A	109.7 (9)	C13—C12—H12A	109.2 (8)
C13—C14—H14B	108.9 (9)	C13—C12—H12B	110.8 (9)
C15—C14—C13	111.11 (10)	C11—C12—H12A	108.9 (8)
C15—C14—H14A	109.2 (9)	C11—C12—H12B	110.0 (9)
C15—C14—H14B	109.8 (9)	H12A—C12—H12B	106.0 (12)
H14A—C14—H14B	108.0 (12)	C14—C13—H13A	107.7 (9)
C19—C18—C17	128.07 (11)	C14—C13—H13B	109.8 (9)
C19—C18—H18	116.3 (9)	C12—C13—C14	110.15 (10)
C17—C18—H18	115.5 (9)	C12—C13—H13A	110.0 (9)
C18—C19—C20	120.79 (11)	C12—C13—H13B	110.4 (9)
C18—C19—H19	120.9 (10)	H13A—C13—H13B	108.8 (12)
C20—C19—H19	118.3 (10)	C8—C9—H9	115.5 (9)
C3—C4—C5	116.89 (11)	C10—C9—C8	124.58 (11)
C3—C4—H4	121.4 (9)	C10—C9—H9	119.9 (9)
C5—C4—H4	121.7 (9)	C16—C11—H11	107.0 (8)
C17—C16—C11	111.83 (9)	C12—C11—C16	112.87 (10)
C17—C16—H16	106.3 (8)	C12—C11—H11	106.4 (8)
C11—C16—H16	106.0 (8)	C10—C11—C16	110.93 (9)
C15—C16—C17	114.84 (10)	C10—C11—C12	110.45 (10)
C15—C16—C11	110.08 (9)	C10—C11—H11	109.0 (8)
C15—C16—H16	107.2 (8)	C9—C10—C11	123.82 (11)
C18—C17—C16	110.54 (9)	C9—C10—H10	119.5 (9)
C18—C17—C8	108.26 (9)	C11—C10—H10	116.7 (9)
C18—C17—H17	110.5 (8)	C22—C23—H23A	110.8 (11)
C16—C17—C8	109.30 (9)	C22—C23—H23B	110.0 (11)
C16—C17—H17	110.5 (8)	C22—C23—H23C	110.8 (11)
C8—C17—H17	107.6 (8)	H23A—C23—H23B	108.3 (15)
O1—C2—C3	109.80 (10)	H23A—C23—H23C	109.1 (16)
C7—C2—O1	127.48 (10)	H23B—C23—H23C	107.8 (15)
C7—C2—C3	122.71 (11)	C14—C15—C16	113.29 (10)
C21—C22—H22	106.4 (8)	C14—C15—H15A	108.9 (8)
C23—C22—C21	110.96 (11)	C14—C15—H15B	110.5 (9)
C23—C22—H22	108.2 (9)	C16—C15—H15A	108.7 (8)
C24—C22—C21	111.12 (11)	C16—C15—H15B	109.8 (9)
C24—C22—C23	110.86 (11)	H15A—C15—H15B	105.3 (12)
C24—C22—H22	109.2 (9)	O1—C1—O2	108.07 (9)
C6—C8—C17	111.47 (9)	O1—C1—H1A	109.5 (9)
C6—C8—H8	108.3 (8)	O1—C1—H1B	109.9 (9)
C17—C8—H8	106.4 (8)	O2—C1—H1A	108.7 (9)
C9—C8—C6	111.81 (9)	O2—C1—H1B	108.4 (9)
C9—C8—C17	111.61 (9)	H1A—C1—H1B	112.2 (12)
C9—C8—H8	107.0 (9)	C22—C24—H24A	110.3 (10)
O2—C3—C2	110.17 (10)	C22—C24—H24B	110.8 (11)
C4—C3—O2	128.50 (11)	C22—C24—H24C	112.1 (10)
C4—C3—C2	121.32 (11)	H24A—C24—H24B	106.4 (14)
C6—C5—C4	122.06 (11)	H24A—C24—H24C	107.5 (14)
C6—C5—H5	119.5 (9)	H24B—C24—H24C	109.5 (14)

O1—C2—C3—O2	0.14 (14)	C3—O2—C1—O1	2.82 (12)
O1—C2—C3—C4	178.82 (11)	C3—C4—C5—C6	0.73 (18)
C7—C6—C8—C17	89.64 (12)	C5—C6—C8—C17	−88.97 (13)
C7—C6—C8—C9	−36.07 (14)	C5—C6—C8—C9	145.33 (11)
C7—C6—C5—C4	−0.73 (18)	C5—C4—C3—O2	178.46 (11)
C7—C2—C3—O2	−179.54 (11)	C5—C4—C3—C2	0.05 (18)
C7—C2—C3—C4	−0.87 (19)	C20—N1—C21—C22	103.43 (13)
C6—C7—C2—O1	−178.77 (11)	C21—N1—C20—O3	2.70 (18)
C6—C7—C2—C3	0.86 (17)	C21—N1—C20—C19	−178.39 (10)
C6—C8—C9—C10	140.17 (12)	C12—C11—C10—C9	−109.46 (13)
C18—C19—C20—O3	−5.24 (18)	C13—C14—C15—C16	−55.96 (13)
C18—C19—C20—N1	175.83 (11)	C13—C12—C11—C16	54.57 (13)
C18—C17—C8—C6	70.41 (12)	C13—C12—C11—C10	179.40 (10)
C18—C17—C8—C9	−163.77 (10)	C11—C16—C17—C18	−179.76 (9)
C19—C18—C17—C16	135.66 (13)	C11—C16—C17—C8	61.18 (12)
C19—C18—C17—C8	−104.64 (14)	C11—C16—C15—C14	52.15 (13)
C16—C17—C8—C6	−169.12 (9)	C11—C12—C13—C14	−56.40 (13)
C16—C17—C8—C9	−43.30 (12)	C23—C22—C21—N1	165.79 (11)
C16—C11—C10—C9	16.46 (16)	C15—C14—C13—C12	56.89 (13)
C17—C18—C19—C20	173.97 (11)	C15—C16—C17—C18	−53.39 (13)
C17—C16—C11—C12	77.81 (12)	C15—C16—C17—C8	−172.45 (9)
C17—C16—C11—C10	−46.76 (13)	C15—C16—C11—C12	−51.11 (13)
C17—C16—C15—C14	−75.12 (13)	C15—C16—C11—C10	−175.68 (10)
C17—C8—C9—C10	14.53 (16)	C1—O1—C2—C7	−178.70 (12)
C2—O1—C1—O2	−2.74 (12)	C1—O1—C2—C3	1.63 (13)
C2—C7—C6—C8	−178.69 (10)	C1—O2—C3—C4	179.60 (12)
C2—C7—C6—C5	−0.07 (17)	C1—O2—C3—C2	−1.84 (13)
C8—C6—C5—C4	177.87 (11)	C24—C22—C21—N1	−70.39 (13)
C8—C9—C10—C11	−0.56 (19)

Hydrogen-bond geometry (Å, º) top

Cg2 is the centroid of the benzene ring C2–C7.

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O3ⁱ	0.896 (16)	2.105 (16)	2.8938 (13)	146.3 (13)
C7—H7···O1ⁱⁱ	0.984 (16)	2.503 (16)	3.4264 (15)	156.3 (12)
C1—H1B···Cg2ⁱ	0.978 (16)	2.595 (15)	3.4578 (12)	147.4 (11)

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

Hydrogen-bond geometry (Å, º) top

Cg2 is the centroid of the benzene ring C2–C7.

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O3ⁱ	0.896 (16)	2.105 (16)	2.8938 (13)	146.3 (13)
C7—H7···O1ⁱⁱ	0.984 (16)	2.503 (16)	3.4264 (15)	156.3 (12)
C1—H1B···Cg2ⁱ	0.978 (16)	2.595 (15)	3.4578 (12)	147.4 (11)

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

Acknowledgements

BNL thanks the Alexander von Humboldt Foundation for providing a fellowship to study at Bielefeld University.

References

Agilent (2013). CrysAlis PRO. Agilent Technologies, Yarnton, England. Google Scholar
Balawsnt, S. J., Nerayanan, V., Dillip, H. G., Veakstachahm, B. & Wolfgang, V. P. (1975). Helv. Chim. Acta, 58, 2295–2305. Google Scholar
Chouna, J. R., Nkeng-Efouet, P. A., Lenta, B. N., Wansi, D. J., Neumann, B., Stammler, H.-G., Fon Kimbu, S. & Sewald, N. (2011). Helv. Chim. Acta, 94, 1071–1076. CSD CrossRef CAS Google Scholar
Chouna, J. R., Nkeng-Efouet, P. A., Lenta, B. N., Devkota, K. P., Neumann, B., Stammler, H. G., Kimbu, S. F. & Sewald, N. (2009). Phytochemistry, 70, 684–688. Web of Science CSD CrossRef PubMed CAS Google Scholar
Chouna, J. R., Nkeng-Efouet, P. A., Lenta, B. N., Wansi, J. D., Kimbu, S. F. & Sewald, N. (2010). Phytochemistry Lett. 3, 13–16. Web of Science CrossRef CAS Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
Lenta, B. N., Chouna, J. R., Nkeng-Efouet, P. A., Kimbu, S. F., Tsamo, E. & Sewald, N. (2011). Nat. Prod. Commun. 6, 1591–1592. Web of Science CAS PubMed Google Scholar
Lenta, B. N., Tantangmo, F., Devkota, K. P., Wansi, J. D., Chouna, J. R., Soh, R. C. F., Neumann, B., Stammler, H.-G., Tsamo, E. & Sewald, N. (2009). J. Nat. Prod. 72, 2130–2134. Web of Science CSD CrossRef PubMed CAS Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 71| Part 7| July 2015| Pages o457-o458

doi:10.1107/S2056989015010567

Open

access

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Plain Text

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Plain Text

Search IUCr Journals		doi		Advanced search
Author		volume	page

organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Crystal structure of obscurine: a natural product isolated from the stem bark of B. obscura

1. Related literature

2. Experimental

2.1. Crystal data

2.2. Data collection

2.3. Refinement

Supporting information

Acknowledgements

References

organic compounds