Dimethyl 6H,12H-5,11-methano­dibenzo[b,f][1,5]diazo­cine-2,8-diacetate

Masoud Faroughi; Paul Jensen; Andrew C Try

doi:10.1107/S1600536808001918

. 2008 Jan 23;64(Pt 2):o500. doi: 10.1107/S1600536808001918

Dimethyl 6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine-2,8-diacetate

Masoud Faroughi ^a, Paul Jensen ^b, Andrew C Try ^c,^*

PMCID: PMC2960187 PMID: 21201521

Abstract

The asymmetric unit of the title compound, C₂₁H₂₂N₂O₄, a Tröger’s base analogue derived from methyl 4-aminophenylacetate, contains two crystallographically independent molecules with dihedral angles of 88.44 (5) and 88.68 (6)° between the two benzene rings.

Related literature

For related literature, see: Faroughi et al. (2006 ▶, 2007 ▶, 2008a ▶,b ▶); Solano et al. (2005 ▶); Bag & Maitra (1995 ▶).

Experimental

Crystal data

C₂₁H₂₂N₂O₄
M _r = 366.41
Monoclinic,
a = 11.559 (1) Å
b = 10.957 (1) Å
c = 28.976 (3) Å
β = 100.080 (1)°
V = 3613.2 (6) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 150 (2) K
0.50 × 0.39 × 0.36 mm

Data collection

Bruker SMART 1000 CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.919, T _max = 0.967
35113 measured reflections
8689 independent reflections
5732 reflections with I > 2σ(I)
R _int = 0.036

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.138
S = 1.01
8689 reflections
491 parameters
H-atom parameters constrained
Δρ_max = 0.44 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: SMART (Bruker, 1998 ▶); 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 ▶) and SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: modiCIFer (Guzei, 2005 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808001918/hk2419sup1.cif

e-64-0o500-sup1.cif^{(31.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808001918/hk2419Isup2.hkl

e-64-0o500-Isup2.hkl^{(425KB, hkl)}

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

Acknowledgments

The authors thank the Australian Research Council for a Discovery Project grant to ACT (grant No. DP0345180) and Macquarie University for the award of a Macquarie University Research Development grant to ACT.

supplementary crystallographic information

Comment

The near perpendicular arrangement of the aryl rings in Tröger's base analogues is a result of the methano-strap that is connected to the two nitrogen atoms in the diazocine bridge. Changing the length of this strap has significant effects on the geometry of the resultant compounds, with straps of three and four atoms creating a larger cavity (Faroughi et al., 2007) and a strap of two atoms creating a smaller cavity (Faroughi et al., 2007, 2008a,b). However, even within the methano-strapped family of simple dibenzo Tröger's base analogues there is significant variation of 26° in the dihedral angle that has been measured to lie between 82° (Solano et al., 2005) and 108.44 (4)° (Faroughi et al., 2006). Both types of molecules in the asymmetric unit of (I) shown in Fig. 1 lie toward the middle of this range, with dihedral angles of 91.56 (5)° and 91.32 (6)°.

Experimental

The title compound was prepared according to the literature procedure (Bag & Maitra, 1995). For the preparation of the title compound, methyl 4-aminophenyl- acetate (4.14 g, 25.1 mmol) and paraformaldehyde (1.21 mg, 40.16 mmol) were dissolved in trifluoroacetic acid (50 ml) and the mixture was stirred under an argon atmosphere in the dark for 8 d. The reaction mixture was then treated with a solution of concentrated ammonia (55 ml) in water (100 ml) and further basified by the addition of a saturated sodium hydrogen carbonate solution (150 ml). The crude material was extracted into dichloromethane (3 x 75 ml) and the combined organic layers were washed with brine (100 ml), dried over anhydrous sodium sulfate, filtered and evaporated to dryness to yield brown solid. The crude material was chromatographed (silica gel, ethyl acetate:dichloromethane 1:3) to afford the title compound, (I), (2.82 g, 61%) as a white solid. Single crystals of (I) were produced from slow evaporation of a dichloromethane solution.