6-Meth­oxy-1-(4-meth­oxy­phen­yl)-1,2,3,4-tetra­hydro-9H-β-carbolin-2-ium acetate

Teik Beng Goh; Mohd Nizam Mordi; Sharif Mahsufi Mansor; Mohd Mustaqim Rosli; Hoong-Kun Fun

doi:10.1107/S1600536812016753

. 2012 Apr 21;68(Pt 5):o1483. doi: 10.1107/S1600536812016753

6-Methoxy-1-(4-methoxyphenyl)-1,2,3,4-tetrahydro-9H-β-carbolin-2-ium acetate

Teik Beng Goh ^a, Mohd Nizam Mordi ^a, Sharif Mahsufi Mansor ^a, Mohd Mustaqim Rosli ^b, Hoong-Kun Fun ^b,^*

PMCID: PMC3344593 PMID: 22590355

Abstract

In the title compound, C₁₉H₂₁N₂O₂ ⁺·C₂H₃O₂ ⁻, the 1H-indole ring system is essentially planar [maximum deviation = 0.0257 (14) Å] and forms a dihedral angle of 87.92 (7) Å with the benzene ring attached to the tetrahydropyridinium fragment. The tetrahydropyridinium ring adopts a half-chair conformation. In the crystal, cations and anions are linked by interionic N—H⋯O, C—H⋯O and C—H⋯N hydrogen bonds into chains along the a axis.

Related literature

For the biological activity of metal complexes with 6-methoxy-1-methyl-4,9-dihydro-3H-pyrido[3,4-b]indole, see: Al-Allaf et al. (1990 ▶); Herraiz et al. (2003 ▶). For a related tetrachloridozincate structure, see: Goh et al. (2012 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₁₉H₂₁N₂O₂ ⁺·C₂H₃O₂ ⁻
M _r = 368.42
Monoclinic,
a = 9.1046 (4) Å
b = 19.8837 (8) Å
c = 12.0856 (5) Å
β = 123.281 (3)°
V = 1829.06 (15) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 K
0.28 × 0.24 × 0.16 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.974, T _max = 0.985
21273 measured reflections
6211 independent reflections
4350 reflections with I > 2σ(I)
R _int = 0.045

Refinement

R[F ² > 2σ(F ²)] = 0.056
wR(F ²) = 0.134
S = 1.03
6211 reflections
247 parameters
H-atom parameters constrained
Δρ_max = 0.42 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812016753/rz2738sup1.cif

e-68-o1483-sup1.cif^{(21.9KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812016753/rz2738Isup2.hkl

e-68-o1483-Isup2.hkl^{(304KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812016753/rz2738Isup3.cml

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
N2—H1⋯O3ⁱ	0.93	1.86	2.7762 (15)	169
N1—H2⋯O3	0.90	1.93	2.7895 (19)	160
N2—H3⋯O4ⁱⁱ	0.97	1.72	2.6800 (18)	171
C9—H9A⋯O3ⁱⁱ	0.99	2.52	3.285 (2)	134
C10—H10A⋯N1ⁱ	1.00	2.55	3.4038 (19)	143
C15—H15A⋯O4ⁱⁱⁱ	0.95	2.60	3.5073 (19)	160

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

Acknowledgments

This work was supported by USM Research University Grant No. 1001/CDADAH/815020 and the R&D Initiative Fund, Ministry of Science, Technology and Innovation, Malaysia (MOSTI). HKF thanks USM for the Research University Grant No. 1001/PFIZIK/811160.

supplementary crystallographic information

Comment

The metal complexes of 6-methoxy-1-methyl-4,9-dihydro-3H-β-carboline and other carboline alkaloids were previously reported to have biological activity (Al-Allaf et al. 1990). It is now well established that these class of beta carboline alkaloids may occur under mild conditions in foods from a Pictet-Spengler condensation of indoleamines such as L-tryptophan and short aliphatic aldehydes (Herraiz et al. 2003). Our present work intend to synthesize this compound and prepare it in salt form to investigate its safety and antiproliferative efficacy in cancer cell line.

All bond lengths and angles in the title compound (Fig. 1) are within normal ranges and comparable with those observed for a related compound recently reported (Goh et al., 2012). The 1H-indole ring (C1—C7/C11/N1) is planar with a maximum deviation of 0.0257 (14) Å for atom C11 and forms a dihedral angle of 87.92 (7)° with the C13—C18 benzene ring. The tetrahydropyridinium ring show a half-chair conformation with puckering parameters Q = 0.5216 (16) Å, θ = 52.70 (18)° and φ = 23.4 (2)°. In the crystal structure, cations and anions are linked by intermolecular N—H···O, C—H···O and C—H···N interactions (Table 1) into one-dimensional chains along the a axis (Fig. 2).

Experimental

6-Methoxy-1-(4-methoxyphenyl)-4,9-dihydro-3H-β-carboline (2.50 mmol, 770 mg) was dissolved in analytical grade dichloromethane (0.60 ml). Vortex was performed to aid mixing. Glacial acetic acid (99.5%, 2.50 mmol, 145 µl) was transferred by a micropipette (50–200 µl) and was then added to the 6-methoxy-1-(4-methoxyphenyl)-4,9-dihydro-3H-β-carboline solution dropwise in a 20 ml glass bottle. The side of the glass bottle was scratched with a small spatula and the bottle was kept in fridge at 4° C for 60 days before yielding colourless crystals of 6-methoxy-1-(4-methoxyphenyl)-4,9-dihydro-3H-β-carbolinium acetate which were filtered off, washed twice with acetone and air-dried. Crystals of the title compound suitable for X-ray diffraction analysis were selected directly from the sample as prepared.