4-Meth­oxy­benzoyl-meso-octa­methyl­calix[2]pyrrolidino[2]pyrrole: an acyl chloride derivative of a partially reduced calix[4]pyrrole

Guillaume Journot; Reinhard Neier; Helen Stoeckli-Evans

doi:10.1107/S1600536812008008

. 2012 Mar 7;68(Pt 4):o929–o930. doi: 10.1107/S1600536812008008

4-Methoxybenzoyl-meso-octamethylcalix[2]pyrrolidino[2]pyrrole: an acyl chloride derivative of a partially reduced calix[4]pyrrole

Guillaume Journot ^a, Reinhard Neier ^a,^*, Helen Stoeckli-Evans ^b,^*

PMCID: PMC3343912 PMID: 22589993

Abstract

In the title compound, C₃₆H₅₀N₄O₂, the two pyrrolidine rings have envelope conformations. The conformation of the macrocycle is stabilized by N—H⋯N hydrogen bonds and a C—H⋯N interaction. The benzoyl ring is inclined to an adjacent pyrrole ring by 6.76 (9)°, with a centroid-to-centroid distance of 3.6285 (10) Å. In the crystal, apart from a C—H⋯O and a C—H⋯π interaction, molecules are linked via an N—H⋯O hydrogen bond, leading to the formation of helical chains propagating along [010].

Related literature

For the heterogeneous catalytic hydrogenation of meso-octamethylcalix[4]pyrrole, which gave meso-octamethylcalix[2]pyrrole[2]pyrrolidine, see: Blangy et al. (2009 ▶). For the N-acylation of pyrrolidines using substituted benzoyl chlorides, see: Journot et al. (2012a ▶); Zhang et al. (2009 ▶). For the synthesis and reactivity of the title compound, see: Journot & Neier (2012 ▶). For the crystal structures of similar compounds, see: Journot et al. (2012b ▶,c ▶,d ▶,e ▶)

Experimental

Crystal data

C₃₆H₅₀N₄O₂
M _r = 570.80
Monoclinic,
a = 10.3150 (4) Å
b = 11.8104 (5) Å
c = 26.1856 (10) Å
β = 98.629 (3)°
V = 3153.9 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 173 K
0.40 × 0.39 × 0.39 mm

Data collection

Stoe IPDS II diffractometer
Absorption correction: multi-scan (MULABS in PLATON; Spek, 2009 ▶) T _min = 0.893, T _max = 1.000
33803 measured reflections
5943 independent reflections
4470 reflections with I > 2σ(I)
R _int = 0.063

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.097
S = 1.03
5943 reflections
393 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2009 ▶); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2009 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97, PLATON and publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812008008/aa2052sup1.cif

e-68-0o929-sup1.cif^{(43.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812008008/aa2052Isup2.hkl

e-68-0o929-Isup2.hkl^{(291KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812008008/aa2052Isup3.cml

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

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

Cg1 is the centroid of the pyrrole ring N2/C3/C4/C25/C26 and Cg2 is the centroid of the benzene ring C30–C35.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2A⋯N3	0.88	2.57	3.0671 (18)	117
N4—H4A⋯N3	0.88	2.33	2.8759 (18)	121
C28—H28B⋯N4	0.98	2.59	3.561 (2)	171
C28—H28B⋯Cg1	0.98	2.45	3.3632 (18)	155
N3—H3N⋯O1ⁱ	0.924 (18)	2.283 (18)	3.1401 (17)	154.0 (15)
C20—H20B⋯O1ⁱ	0.98	2.56	3.530 (2)	170
C15—H15A⋯Cg2ⁱ	0.98	2.85	3.7176 (19)	148

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Symmetry code: (i) Inline graphic .

Acknowledgments

HSE thanks the staff of the XRD Application Laboratory, CSEM, Neuchâtel, for access to the X-ray diffraction equipment.

supplementary crystallographic information

Comment

We have recently reported the access to new macrocycles by heterogeneous catalytic hydrogenation of meso-octamethylcalix[4]pyrrole, which gave meso-octamethylcalix[2]pyrrole[2]pyrrolidine (1 in Fig. 3) (Blangy et al., 2009). It was decided to investigate the nucleophilicity of this new macrocycle, which showed interesting reactivity (Journot & Neier, 2012), by reacting different substituted benzoyl chlorides with the macrocycle under smooth conditions (Journot et al., 2012a; Zhang et al., 2009). Herein, we report on the synthesis and crystal structure of the title 4-methoxybenzoyl derivative, one of five compounds that have been studied by X-ray diffraction analysis (Journot et al., 2012b,c,d,e).

The molecular structure of the title compound is given in Fig. 1. The two pyrrolidine rings (N1,C1,C12–C14) and (N3,C6,C7,C21,C22) have envelope conformations with, respectively, atoms C14 and C7 as the flaps. The conformation of the macrocycle is stabilized by intramolecular N—H···N hydrogen bonds involving atom N3 and the two pyrrole H atoms, H2 and H4 (Table 1). The benzoyl ring (C30–C35) is inclined to the pyrrole ring (N2,C3,C4,C25,C26) by 6.76 (9)°, with a centroid-to-centroid distance of 3.6285 (10) Å. The methyl group C28 is also in close contact with the pyrrole ring (N4,C9,C10,C17,C18), with a short C28—H28A···N4 interaction and a C28—H28A···centroid distance of 3.3632 (18) Å (Table 1).

In the crystal, molecules are linked via an N—H···O hydrogen bond, involving the N3 pyrrolidine H atom (H3N) and the benzoyl O atom (O1), leading to the formation of helical chains propagating along [010] (Fig. 2 and Table 1). The same O atom is involved in a C—H···O contact with methyl group C20. A C—H···π interaction is also observed, involving the methyl group C15 and the benzoyl ring (C30–C35) (see Table 1).

The overall geometry and crystal packing is very similar to that reported for the 4-chlorobenzoyl derivative (Journot et al., 2012b), and the 4-nitrobenzoyl (Journot et al., 2012d) and 4-methylbenzoyl (Journot et al., 2012e) derivatives. The benzoyl derivative (Journot et al., 2012c) crystallized in the trigonal space group R3, as a partial (0.25H₂O) hydrate, and forms hydrogen bonded chains propagating along [001].

Experimental

General procedure for the N-acylation of meso-octamethylcalix[2]pyrrolidino[2]pyrrole (1) is illustrated in Fig. 3. The full details of this synthesis will be reported elsewhere (Journot & Neier, 2012). The title amide 3e was prepared, according to the general procedure, from 100 mg of 1 (0.23 mmol), 4-methoxybenzoyl chloride (2e, 64.93 µl, 0.48 mmol), potassium carbonate (70 mg, 0.48 mmol) in THF (5 ml) and ACN (2.5 ml). The residue was purified by column chromatography (SiO₂, CH₂Cl₂/MeOH, 97/3) to yield 117.0 mg (90%) of colourless crystals of the title compound (3e). Melting point: 488 K. HRMS calcd. for C₃₆H₅₀N₄O₂+H⁺ 571.4007, found 571.3993. Further synthetic and spectroscopic data has been reported elsewhere (Journot & Neier, 2012).