Methyl 7-oxo-12-propyl­amino-13-nitro­deisopropyl­dehydro­abietate

Kai Wang; Ye Zhang; Xiang-Hui Yi; Yong Zhang; Ying-Ming Pan

doi:10.1107/S1600536810032824

. 2010 Sep 25;66(Pt 10):o2604. doi: 10.1107/S1600536810032824

Methyl 7-oxo-12-propylamino-13-nitrodeisopropyldehydroabietate

Kai Wang ^a,^b, Ye Zhang ^b, Xiang-Hui Yi ^b,^*, Yong Zhang ^c, Ying-Ming Pan ^a

PMCID: PMC2983386 PMID: 21587581

Abstract

In the title compound, C₂₁H₂₈N₂O₅ (systematic name: methyl 1,4a-dimethyl-7-nitro-9-oxo-6-propylamino-1,2,3,4,4a,9,10,10a-octahydrophenanthrene-1-carboxylate) the cyclohexane ring (A) and the central cyclohexene ring (B) exist at a trans ring junction, with the two methyl groups in the axial positions of the six-membered rings. Ring A has a chair conformation and ring B a half-chair conformation. An intramolecular N—H⋯O hydrogen bond occurs. The crystal structure is stabilized by intermolecular C—H⋯O and N—H⋯O interactions.

Related literature

For inhibition of viruses by resin acid derivatives, see: Fonseca et al. (2004 ▶); Gigante et al. (2003 ▶). For related structures, see: Hamodrakas et al. (1978 ▶); Silvestre et al. (1998 ▶).

Experimental

Crystal data

C₂₁H₂₈N₂O₅
M _r = 388.45
Orthorhombic,
a = 8.2915 (15) Å
b = 11.344 (2) Å
c = 20.288 (4) Å
V = 1908.3 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 223 K
0.40 × 0.18 × 0.14 mm

Data collection

Rigaku Saturn diffractometer
Absorption correction: multi-scan (Jacobson, 1998 ▶) T _min = 0.956, T _max = 0.987
9263 measured reflections
2492 independent reflections
2249 reflections with I > 2σ(I)
R _int = 0.047

Refinement

R[F ² > 2σ(F ²)] = 0.061
wR(F ²) = 0.122
S = 1.19
2492 reflections
262 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.16 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Data collection: CrystalClear (Rigaku, 1999 ▶); cell refinement: CrystalClear; data reduction: CrystalStructure (Rigaku/MSC, 2000 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810032824/ng5010sup1.cif

e-66-o2604-sup1.cif^{(23.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810032824/ng5010Isup2.hkl

e-66-o2604-Isup2.hkl^{(122.4KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O3	0.93 (4)	1.94 (4)	2.654 (4)	133 (3)
C8—H8B⋯O3ⁱ	0.98	2.55	3.454 (4)	154
C15—H15A⋯O1ⁱⁱ	0.98	2.40	3.344 (4)	161

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors thank the National Natural Science Foundation of China (No. 20762001), Guangxi’s Medicine Talented Persons Small Highland Foundation (0808) and the Guangxi Department of Education research project (200911MS281, 200911MS282) for support.

supplementary crystallographic information

Comment

As the main components of rosin, abietic acid and dehydroabietic acid are tricyclic diterpene carboxylic acids. It have been demonstrated that resin acid derivatives exhibit inhibition activity against viruses by recent works (Gigante et al., 2003; Fonseca et al., 2004), which prompted us to synthesis of the title compound. In the cation of the title compounds (Fig.1), rings A (atoms C9—C14) and rings B (atoms C5—C10) demonstrate a trans ring junction with the torsion angles showing classical chair and halfchair conformations for rings A and B, respectively. There are two methyl groups in the axial positions of the six-membered rings and the overall geometric parameters of the title compound are comparable to those of 12-acetyl-dehydroabietate (Silvestre, et al., 1998) and methyl dehydroabietate (Hamodrakas, et al., 1978), apart from the substituted nitro group and propylamino at the benzene ring.

It should be noted that there are weak intermolecular C—H···O and N—H···O hydrogen bonds in the packing view, which link the molecules into a one-dimensional chain to stabilize the structure (Fig. 2).

The absolute configuration of the title compound could not determined from anomalous scattering effects because none heavier atoms than Si are present. However, NMR studies of analgous compounds suggest that the configuration is retained through the course of the reaction.Therefore, the absolute configuration of the title compound is assumed from the known absolute configuration of methyl dehydroabietate (Hamodrakas, et al., 1978).

Experimental

Methyl 7-oxo-12-bromo-13-nitro-deisopropyldehydroabietate (2.5 mmol), potassium carbonate (1.0 mmol), cuprous chloride (2.0 mmol) were added to 15 ml DMF. After stirring for 10 min, n-propylamine (2.5 mmol) was added drop-wise. The resultant solution was refluxed for 4 h, and then plenty of ice water was added, a lot of orange-yellow solid was precipitated, filtered, washed with water, and then dried. Upon recrystallization from ethanol, pale orange crystls were obtained (Yield 78.9%, m.p. 455–456 k).