5-Bromo-17-nitro-26,28-prop-2-en­oxy-25,27-dipropoxycalix[4]arene

Catharina Hippius; Frank Würthner; Michael Bolte

doi:10.1107/S160053680900659X

. 2009 Feb 28;65(Pt 3):o617. doi: 10.1107/S160053680900659X

5-Bromo-17-nitro-26,28-prop-2-enoxy-25,27-dipropoxycalix[4]arene

Catharina Hippius ^a, Frank Würthner ^a, Michael Bolte ^b,^*

PMCID: PMC2968623 PMID: 21582269

Abstract

Molecules of the title compound, C₄₀H₄₂BrNO₆, are located on a crystallographic twofold rotation axis. As a result, the nitro group and bromine residue are mutually disordered with equal occupancies. The propoxy-substituted aromatic rings are close to parallel to each other [dihedral angle = 21.24 (1)°], whereas the propenoxy-substituted rings enclose a dihedral angle of 70.44 (1)°. The dihedral angles between the methylene C atoms and the aromatic rings shows that the propenoxy substituted rings are bent away from the calixarene cavity [dihedral angle between the planes = 35.22 (8)°], whereas the propoxy-substituted rings are almost perpendicular [79.38 (10)°] to the plane of the methylene C atoms.

Related literature

For related literature on calix[4]arenes, see: Asfari et al. (2001 ▶); Böhmer (1995 ▶); Gutsche (1998 ▶); Mandolini & Ungaro (2000 ▶). For the synthesis of the title compound, see: Sansone et al. (2004 ▶).

Experimental

Crystal data

C₄₀H₄₂BrNO₆
M _r = 712.66
Monoclinic,
a = 25.001 (3) Å
b = 8.4963 (14) Å
c = 19.909 (3) Å
β = 121.530 (8)°
V = 3604.6 (9) Å³
Z = 4
Mo Kα radiation
μ = 1.19 mm⁻¹
T = 173 K
0.26 × 0.12 × 0.11 mm

Data collection

Stoe IPDS-II two-circle diffractometer
Absorption correction: multi-scan (MULABS; Spek, 2009 ▶; Blessing, 1995 ▶) T _min = 0.748, T _max = 0.881
9833 measured reflections
3366 independent reflections
1538 reflections with I > 2σ(I)
R _int = 0.081

Refinement

R[F ² > 2σ(F ²)] = 0.065
wR(F ²) = 0.130
S = 0.92
3366 reflections
286 parameters
47 restraints
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2001 ▶); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680900659X/at2726sup1.cif

e-65-0o617-sup1.cif^{(24.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680900659X/at2726Isup2.hkl

e-65-0o617-Isup2.hkl^{(165.2KB, hkl)}

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

supplementary crystallographic information

Comment

Calix[4]arenes are macrocycles which provide an ideal scaffold to preorganize functional units for application in catalysis or molecular recognition. They are available in large quantities and can be easily modified by selective reactions involving the wide or narrow rim of the molecule (Asfari et al., 2001; Mandolini & Ungaro, 2000; Gutsche, 1998; Böhmer, 1995). Accordingly, compound 1 was obtained by bromination of 5-mononitro-26,28-dipropyloxycalix[4]arene in CH₂Cl₂ with 59% yield (Sansone et al., 2004). Subsequent reaction of 1 with allyl bromide and NaH in DMF at room temperature afforded the respective monoalkylated derivative 2. Further reaction of compound 2 with a large excess of allyl bromide afforded compound 3 with 22% yield.

Molecules of the title compound 3 (Fig. 1) are located on a crystallographic twofold rotation axis. As a result of that, the nitro group and bromine residue are mutually disordered. The propoxy substituted aromatic rings are almost parallel to each other [dihedral angle 21.24 (1)°], whereas the propenoxy substituted rings enclose a dihedral angle of 70.44 (1)°. The dihedral angles between the methylene C atoms and the aromatic rings shows that the propenoxy substituted rings are bent away from the calixarene cavity [dihedral angle between the planes 35.22 (8)°] whereas the propoxy substituted rings are almost perpendicular [79.38 (10)°] to the plane of the methylene C atoms.

Experimental

5-Mononitro-26,28-dipropyloxycalix[4]arene was synthesized according to literature (Sansone et al., 2004). Under an argon atmosphere 29 mg (0.045 mmol, 1 equiv.) of compound 2 and 26 mg (1.12 mmol, 25 equiv.) of NaH were suspended in 2 ml of dry DMF and stirred for some minutes. Afterwards, 135 mg (1.12 mmol, 25 equiv.) of allyl bromide in 0.7 ml DMF were slowly added to the mixture and the latter stirred for additional 12 h at room temperature. Subsequently, the reaction suspension was slowly stirred into a mixture of 20 ml CH₂Cl₂ and 10 ml 1 N HCl. The obtained organic phase was separated, washed with water and brine and dried over MgSO₄. The solvent was evaporated and the resulting crude product was purified by column chromatography with CH₂Cl₂/pentane 40:60 and subsequent crystallization from CHCl₃/methanol. Compound 3 was obtained as white crystals (7 mg, yield 22%). C₄₀H₄₂BrNO₆ (712.67). Mp = 203–206°C. CH₂Cl₂/Hexan 40:60; R_f=0.30. ¹H-NMR (400 MHz, CDCl₃, TMS, 25°C) δ (p.p.m.): 7.80 (s, 2H; Ar-H); 6.96 (s, 2H; Ar-H); 6.50–6.39 (m, 6H; Ar-H); 6.37 - 6.26 (m, 2H; AllylC=H); 5.21–5.16 (m, 4H; AllylC=H₂); 4.66 and 4.64 (dt, 2H, ³J=6.0 Hz, ⁴J=0.98 Hz; O—CH₂Allyl); 4.52 and 4.50 (dt, 2H, ³J=6.5 Hz, ⁴J=1.1 Hz; O—CH₂Allyl); 4.65 and 3.26 (AB, total 4H, ²J=13.6; Ar—CH₂-Ar); 4.36 and 3.11 (AB, total 4H, ²J=13.5; Ar—CH₂-Ar); 3.79 - 3.73 (m, 4H; O—CH₂); 1.93 - 1.85 (m, 4H; propyl), 1.03 (t, 6H, ³J=7.5 Hz; propyl). MS (EI) calc. for C₄₀H₄₂BrNO₆: m/z= 711.22; found m/z= 711.1 [M]⁺.