organic compounds
meso-4,4′-Dimethoxy-2,2′-{[(3aR,7aS)-2,3,3a,4,5,6,7,7a-octahydro-1H-benzimidazole-1,3-diyl]bis(methylene)}diphenol
aUniversidad Nacional de Colombia, Sede Bogotá, Facultad de Ciencias, Departamento de Química, Cra 30 No. 45-03, Bogotá, Código Postal 111321, Colombia, and bInstitute of Physics ASCR, v.v.i., Na Slovance 2, 182 21 Praha 8, Czech Republic
*Correspondence e-mail: ariverau@unal.edu.co
The title compound, C23H30N2O4, a di-Mannich base derived from 4-methoxyphenol and cis-1,2-diaminecyclohexane, has a perhydrobenzimidazolidine nucleus, in which the cyclohexane ring adopts a chair conformation and the heterocyclic ring has a half-chair conformation with a C—N—C—C torsion angles of −48.14 (15) and −14.57 (16)°. The mean plane of the heterocycle makes dihedral angles of 86.29 (6) and 78.92 (6)° with the pendant benzene rings. The molecular structure of the title compound shows the presence of two interactions between the N atoms of the imidazolidine ring and the hydroxyl groups through intramolecular O—H⋯N hydrogen bonds with graph-set motif S(6). The unobserved lone pairs of the N atoms are presumed to be disposed in a syn conformation, being only the second example of an exception to the typical `rabbit-ears' effect in 1,2-diamines.
Related literature
For related structures, see: Rivera et al. (2011, 2013a). For the preparation of the title compound, see: Rivera et al. (2013b). For standard bond lengths, see: Allen et al. (1987). For hydrogen-bond graph-set nomenclature, see: Bernstein et al. (1995). For a discussion of the `rabbit-ear' effect in 1,2-diamines, see: Hutchins et al. (1968). For background to this work, see: Van den Enden & Geise (1981); Geise et al. (1971). For the extinction correction, see: Becker & Coppens (1974).
Experimental
Crystal data
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Data collection: CrysAlis PRO (Agilent, 2010); cell CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis 2007); program(s) used to refine structure: JANA2006 (Petříček et al., 2006); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: JANA2006.
Supporting information
https://doi.org/10.1107/S1600536813015092/sj5324sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536813015092/sj5324Isup2.hkl
A solution of p-methoxyphenol (2.00 mmol) in dioxane (3 ml) was added dropwise to a stirred solution of (2S,7R,11S,16R)-1,8,10,17-tetraazapentacyclo[8.8.1.1.8,170.2,7011,16]icosane (276 mg, 1.00 mmol) in dioxane (3 ml). The mixture was stirred for 15 min at room temperature and then water (4 ml) was added. The mixture was heated at 313 K during 30 h. After cooling to room temperature, the solvent was removed in vacuo and the crude product was purified by
on a silica column and subjected to with light petroleum ether: ethyl acetate (yield 45%, M.p. = 405–406 K). Single crystals of (I) were grown from a CHCl3 solution by slow evaporation of the solvent at room temperature over a period of about 2 weeks.The hydroxyl hydrogen atoms were found in difference Fourier maps and their coordinates were refined with a distance restraint d(O—H) = 0.926 Å with σ 0.01. All other H atoms atoms were kept in the geometrically correct positions with C—H distance 0.96 A. The isotropic atomic displacement parameters of hydrogen atoms were evaluated as 1.2×Ueq of the parent atom.
Structural features and stereochemistry of 1,1- and 1,2-diamine functionalities play an important role in the potential reactivity of cyclic
We have demonstrated that cyclic are precursors of di-Mannich bases, an interesting family of 1,2-diamines, where the lone pairs usually adopt an anti conformation (Rivera, et al. 2011) to avoid electron pair repulsions (the rabbit-ears effect) (Hutchins et al. 1968). Although a syn conformation is not typical in this kind of compounds, we obtained 4,4'-difluoro-2,2'-{[(3aR,7aS)-2,3,3a,4,5,6,7,7a-octahydro-1H-1,3-benzimidazole-1,3-diyl]bis(methylene)}diphenol (Rivera et al., 2013a), one exception of the "rabbit-ears effect" (Hutchins et al., 1968). Here we report the synthesis and of the title compound (I).The molecular structure and atom-numbering scheme for (I) are shown in Fig. 1. The bond lengths are close to normal (Allen et al., 1987). The
of (I) shows two intramolecular hydrogen bonds with graph-set motif S(6) (Bernstein et al., 1995) (Table 1), where the N···H distances and the N···O distances are shorter (by about 0.06 Å and 0.03 Å, respectively) than the observed values in a related structure (Rivera, et al. 2013a). These results suggest that the electronic character of the< i>para substituent in the aromatic rings does not significantly influence the strength of the intermolecular hydrogen bonds in these compounds.The cyclohexane ring adopts a chair conformation where the endocyclic C—C—C bond angles are distorted from the normal tetrahedral bond angles in a chair conformation (Geise et al., 1971), since these values are in the range of 110.29 (15)° to 114.50 (14)°. The imidazolidine ring adopts a half chair conformation (Van den Enden & Geise, 1981), where the nitrogen lone pairs are oriented in a syn disposition and the benzyl groups are located in 1,3-diequatorial positions.
The dihedral angle between the aromatic rings is 49.19 (52) °. The C3—C8 and C6—C4 bonds are the longest and the C10—C12 and C19—C22 bond are the shortest in the aromatic rings.
For related structures, see: Rivera et al. (2011, 2013a). For the preparation of the title compound, see: Rivera et al. (2013b). For standard bond lengths, see: Allen et al. (1987). For hydrogen-bond graph-set nomenclature, see: Bernstein et al. (1995). For a discussion of the `rabbit-ear' effect in 1,2-diamines, see: Hutchins et al. (1968). For background to this work, see: Van den Enden & Geise (1981); Geise et al. (1971). For the extinction correction, see: Becker & Coppens (1974).
Data collection: CrysAlis PRO (Agilent, 2010); cell
CrysAlis PRO (Agilent, 2010); data reduction: CrysAlis PRO (Agilent, 2010); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis 2007); program(s) used to refine structure: JANA2006 (Petříček et al., 2006); molecular graphics: Diamond (Brandenburg & Putz, 2005); software used to prepare material for publication: JANA2006 (Petříček et al. 2006).C23H30N2O4 | F(000) = 856 |
Mr = 398.5 | Dx = 1.300 Mg m−3 |
Orthorhombic, P212121 | Cu Kα radiation, λ = 1.5418 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 3881 reflections |
a = 6.4135 (3) Å | θ = 4.2–67.0° |
b = 11.4099 (6) Å | µ = 0.72 mm−1 |
c = 27.8249 (14) Å | T = 120 K |
V = 2036.15 (18) Å3 | Polygon shape, white |
Z = 4 | 0.21 × 0.13 × 0.13 mm |
Agilent Xcalibur (Atlas, Gemini ultra) diffractometer | 3491 independent reflections |
Radiation source: Enhance Ultra (Cu) X-ray Source | 3103 reflections with I > 3σ(I) |
Mirror monochromator | Rint = 0.023 |
Detector resolution: 10.3784 pixels mm-1 | θmax = 67.1°, θmin = 3.2° |
ω scans | h = −7→4 |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2010) | k = −13→12 |
Tmin = 0.341, Tmax = 1 | l = −30→32 |
5920 measured reflections |
Refinement on F2 | H atoms treated by a mixture of independent and constrained refinement |
R[F > 3σ(F)] = 0.031 | Weighting scheme based on measured s.u.'s w = 1/(σ2(I) + 0.0016I2) |
wR(F) = 0.080 | (Δ/σ)max = 0.014 |
S = 1.13 | Δρmax = 0.11 e Å−3 |
3491 reflections | Δρmin = −0.09 e Å−3 |
269 parameters | Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974) |
1 restraint | Extinction coefficient: 1800 (300) |
114 constraints |
C23H30N2O4 | V = 2036.15 (18) Å3 |
Mr = 398.5 | Z = 4 |
Orthorhombic, P212121 | Cu Kα radiation |
a = 6.4135 (3) Å | µ = 0.72 mm−1 |
b = 11.4099 (6) Å | T = 120 K |
c = 27.8249 (14) Å | 0.21 × 0.13 × 0.13 mm |
Agilent Xcalibur (Atlas, Gemini ultra) diffractometer | 3491 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2010) | 3103 reflections with I > 3σ(I) |
Tmin = 0.341, Tmax = 1 | Rint = 0.023 |
5920 measured reflections |
R[F > 3σ(F)] = 0.031 | 1 restraint |
wR(F) = 0.080 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.13 | Δρmax = 0.11 e Å−3 |
3491 reflections | Δρmin = −0.09 e Å−3 |
269 parameters |
Refinement. The refinement was carried out against all reflections. The conventional R-factor is always based on F. The goodness of fit as well as the weighted R-factor are based on F and F2 for refinement carried out on F and F2, respectively. The threshold expression is used only for calculating R-factors etc. and it is not relevant to the choice of reflections for refinement. The program used for refinement, Jana2006, uses the weighting scheme based on the experimental expectations, see _refine_ls_weighting_details, that does not force S to be one. Therefore the values of S are usually larger than the ones from the SHELX program. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.9143 (2) | 0.54863 (11) | 0.19640 (4) | 0.0301 (4) | |
O2 | 0.5296 (2) | 0.11931 (11) | 0.22143 (5) | 0.0331 (4) | |
O3 | 1.1573 (2) | 0.56734 (11) | 0.02995 (4) | 0.0307 (4) | |
O4 | 0.75546 (19) | 0.25342 (11) | −0.08969 (5) | 0.0323 (4) | |
N1 | 0.6253 (2) | 0.60135 (11) | 0.13114 (5) | 0.0214 (4) | |
N2 | 0.7838 (2) | 0.63852 (12) | 0.05764 (5) | 0.0236 (4) | |
C1 | 0.5156 (3) | 0.31779 (14) | 0.18880 (5) | 0.0235 (5) | |
C2 | 0.6158 (3) | 0.22830 (15) | 0.21334 (6) | 0.0263 (5) | |
C3 | 0.8117 (3) | 0.44415 (15) | 0.20127 (6) | 0.0239 (5) | |
C4 | 0.8426 (3) | 0.51409 (14) | −0.01265 (5) | 0.0227 (4) | |
C5 | 0.7086 (3) | 0.74987 (14) | 0.07934 (6) | 0.0240 (5) | |
C6 | 1.0495 (3) | 0.49232 (15) | 0.00056 (6) | 0.0249 (5) | |
C7 | 0.8898 (3) | 0.80893 (16) | 0.10624 (6) | 0.0291 (5) | |
C8 | 0.6101 (3) | 0.42686 (14) | 0.18311 (5) | 0.0225 (5) | |
C9 | 0.7333 (3) | 0.62223 (15) | 0.00643 (6) | 0.0241 (5) | |
C10 | 1.0459 (3) | 0.31475 (16) | −0.04591 (6) | 0.0299 (5) | |
C11 | 0.4897 (3) | 0.52615 (15) | 0.16028 (6) | 0.0232 (5) | |
C12 | 1.1484 (3) | 0.39175 (15) | −0.01597 (6) | 0.0285 (5) | |
C13 | 0.8412 (3) | 0.33593 (14) | −0.05968 (6) | 0.0253 (5) | |
C14 | 0.7399 (3) | 0.43469 (14) | −0.04254 (6) | 0.0234 (5) | |
C15 | 0.3383 (3) | 0.09474 (15) | 0.19795 (7) | 0.0318 (5) | |
C16 | 0.6655 (3) | 0.84873 (15) | 0.17768 (6) | 0.0296 (5) | |
C17 | 0.6964 (3) | 0.54281 (14) | 0.08724 (6) | 0.0246 (5) | |
C18 | 0.4760 (3) | 0.79993 (15) | 0.15171 (6) | 0.0267 (5) | |
C19 | 0.8144 (3) | 0.24615 (15) | 0.23194 (6) | 0.0277 (5) | |
C20 | 0.8172 (3) | 0.90189 (16) | 0.14189 (7) | 0.0339 (6) | |
C21 | 0.5386 (3) | 0.26108 (18) | −0.09885 (7) | 0.0377 (6) | |
C22 | 0.9116 (3) | 0.35333 (16) | 0.22549 (6) | 0.0273 (5) | |
C23 | 0.5338 (3) | 0.71070 (14) | 0.11279 (6) | 0.0230 (5) | |
H1c1 | 0.379468 | 0.30444 | 0.17556 | 0.0282* | |
H1c5 | 0.65943 | 0.806783 | 0.0566 | 0.0288* | |
H1c7 | 0.969757 | 0.750452 | 0.122842 | 0.0349* | |
H2c7 | 0.983602 | 0.843718 | 0.083447 | 0.0349* | |
H1c9 | 0.777998 | 0.689708 | −0.011408 | 0.0289* | |
H2c9 | 0.585279 | 0.613214 | 0.002786 | 0.0289* | |
H1c10 | 1.11646 | 0.245973 | −0.057325 | 0.0359* | |
H1c11 | 0.380664 | 0.494706 | 0.140473 | 0.0278* | |
H2c11 | 0.424373 | 0.572215 | 0.184908 | 0.0278* | |
H1c12 | 1.289471 | 0.375787 | −0.006445 | 0.0342* | |
H1c14 | 0.597307 | 0.448657 | −0.051337 | 0.028* | |
H1c15 | 0.291175 | 0.017919 | 0.206897 | 0.0381* | |
H2c15 | 0.235901 | 0.151753 | 0.207273 | 0.0381* | |
H3c15 | 0.358284 | 0.097924 | 0.163784 | 0.0381* | |
H1c16 | 0.621918 | 0.907719 | 0.200132 | 0.0355* | |
H2c16 | 0.733433 | 0.786893 | 0.195069 | 0.0355* | |
H1c17 | 0.579091 | 0.508786 | 0.070973 | 0.0295* | |
H2c17 | 0.804762 | 0.487985 | 0.095061 | 0.0295* | |
H1c18 | 0.398726 | 0.863134 | 0.137522 | 0.0321* | |
H2c18 | 0.383947 | 0.763989 | 0.174577 | 0.0321* | |
H1c19 | 0.883769 | 0.184533 | 0.249162 | 0.0333* | |
H1c20 | 0.935569 | 0.932931 | 0.158751 | 0.0407* | |
H2c20 | 0.749972 | 0.964503 | 0.124838 | 0.0407* | |
H1c21 | 0.49724 | 0.198114 | −0.119656 | 0.0453* | |
H2c21 | 0.463462 | 0.255624 | −0.069084 | 0.0453* | |
H3c21 | 0.50801 | 0.334683 | −0.114005 | 0.0453* | |
H1c22 | 1.049675 | 0.365199 | 0.237874 | 0.0327* | |
H1c23 | 0.400514 | 0.701537 | 0.097533 | 0.0276* | |
H1o3 | 1.050 (3) | 0.6060 (18) | 0.0456 (7) | 0.0369* | |
H1o1 | 0.834 (3) | 0.5936 (17) | 0.1758 (7) | 0.0361* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0312 (7) | 0.0281 (7) | 0.0309 (6) | −0.0030 (6) | −0.0068 (5) | 0.0021 (5) |
O2 | 0.0438 (7) | 0.0216 (6) | 0.0340 (6) | 0.0000 (6) | −0.0026 (6) | 0.0074 (5) |
O3 | 0.0261 (6) | 0.0333 (7) | 0.0328 (6) | −0.0028 (6) | −0.0018 (5) | −0.0048 (5) |
O4 | 0.0330 (7) | 0.0310 (7) | 0.0330 (6) | −0.0036 (6) | 0.0062 (5) | −0.0123 (5) |
N1 | 0.0260 (7) | 0.0180 (6) | 0.0202 (6) | 0.0011 (6) | 0.0004 (5) | −0.0003 (5) |
N2 | 0.0321 (8) | 0.0189 (7) | 0.0197 (6) | 0.0012 (6) | −0.0010 (6) | −0.0011 (5) |
C1 | 0.0268 (9) | 0.0236 (9) | 0.0202 (7) | 0.0013 (7) | 0.0010 (7) | 0.0005 (6) |
C2 | 0.0346 (10) | 0.0240 (9) | 0.0204 (7) | 0.0042 (8) | 0.0044 (7) | 0.0022 (6) |
C3 | 0.0284 (9) | 0.0239 (8) | 0.0194 (7) | 0.0018 (7) | −0.0002 (6) | −0.0010 (6) |
C4 | 0.0281 (9) | 0.0227 (8) | 0.0174 (7) | 0.0002 (8) | 0.0035 (7) | 0.0020 (6) |
C5 | 0.0348 (9) | 0.0177 (8) | 0.0195 (7) | 0.0026 (8) | −0.0015 (7) | 0.0017 (6) |
C6 | 0.0268 (8) | 0.0263 (9) | 0.0217 (7) | −0.0038 (7) | 0.0019 (7) | 0.0006 (6) |
C7 | 0.0325 (10) | 0.0258 (9) | 0.0289 (8) | −0.0052 (8) | 0.0034 (7) | −0.0014 (7) |
C8 | 0.0269 (9) | 0.0240 (8) | 0.0165 (7) | 0.0029 (7) | 0.0011 (6) | −0.0014 (6) |
C9 | 0.0283 (9) | 0.0239 (8) | 0.0201 (7) | 0.0014 (7) | −0.0007 (6) | 0.0011 (6) |
C10 | 0.0302 (9) | 0.0242 (9) | 0.0354 (9) | 0.0007 (8) | 0.0105 (8) | −0.0022 (7) |
C11 | 0.0240 (8) | 0.0235 (8) | 0.0220 (7) | 0.0001 (7) | −0.0007 (6) | 0.0015 (6) |
C12 | 0.0255 (9) | 0.0282 (9) | 0.0319 (8) | 0.0009 (8) | 0.0032 (7) | 0.0037 (7) |
C13 | 0.0300 (9) | 0.0223 (8) | 0.0237 (8) | −0.0048 (7) | 0.0062 (7) | −0.0014 (6) |
C14 | 0.0242 (8) | 0.0253 (8) | 0.0206 (7) | −0.0013 (7) | 0.0026 (6) | 0.0005 (6) |
C15 | 0.0360 (10) | 0.0245 (9) | 0.0349 (9) | −0.0012 (8) | 0.0039 (8) | 0.0040 (7) |
C16 | 0.0400 (10) | 0.0239 (8) | 0.0249 (8) | 0.0025 (8) | −0.0039 (8) | −0.0069 (6) |
C17 | 0.0313 (9) | 0.0208 (8) | 0.0217 (7) | 0.0035 (7) | 0.0017 (7) | −0.0003 (6) |
C18 | 0.0305 (9) | 0.0222 (8) | 0.0274 (8) | 0.0053 (8) | 0.0010 (7) | −0.0010 (7) |
C19 | 0.0334 (10) | 0.0275 (9) | 0.0222 (7) | 0.0091 (8) | 0.0003 (7) | 0.0035 (7) |
C20 | 0.0425 (11) | 0.0244 (9) | 0.0348 (9) | −0.0045 (9) | −0.0052 (8) | −0.0047 (7) |
C21 | 0.0345 (10) | 0.0397 (11) | 0.0389 (10) | −0.0068 (9) | 0.0015 (8) | −0.0152 (8) |
C22 | 0.0255 (9) | 0.0341 (9) | 0.0223 (8) | 0.0052 (8) | −0.0024 (7) | 0.0008 (7) |
C23 | 0.0248 (9) | 0.0202 (8) | 0.0239 (7) | 0.0020 (7) | −0.0033 (7) | 0.0002 (6) |
O1—C3 | 1.368 (2) | C9—H1c9 | 0.96 |
O1—H1o1 | 0.93 (2) | C9—H2c9 | 0.96 |
O2—C2 | 1.380 (2) | C10—C12 | 1.378 (3) |
O2—C15 | 1.418 (2) | C10—C13 | 1.389 (3) |
O3—C6 | 1.371 (2) | C10—H1c10 | 0.96 |
O3—H1o3 | 0.93 (2) | C11—H1c11 | 0.96 |
O4—C13 | 1.373 (2) | C11—H2c11 | 0.96 |
O4—C21 | 1.417 (2) | C12—H1c12 | 0.96 |
N1—C11 | 1.466 (2) | C13—C14 | 1.385 (2) |
N1—C17 | 1.465 (2) | C14—H1c14 | 0.96 |
N1—C23 | 1.470 (2) | C15—H1c15 | 0.96 |
N2—C5 | 1.487 (2) | C15—H2c15 | 0.96 |
N2—C9 | 1.473 (2) | C15—H3c15 | 0.96 |
N2—C17 | 1.478 (2) | C16—C18 | 1.520 (3) |
C1—C2 | 1.386 (2) | C16—C20 | 1.519 (3) |
C1—C8 | 1.393 (2) | C16—H1c16 | 0.96 |
C1—H1c1 | 0.96 | C16—H2c16 | 0.96 |
C2—C19 | 1.390 (3) | C17—H1c17 | 0.96 |
C3—C8 | 1.402 (2) | C17—H2c17 | 0.96 |
C3—C22 | 1.392 (2) | C18—C23 | 1.532 (2) |
C4—C6 | 1.399 (3) | C18—H1c18 | 0.96 |
C4—C9 | 1.515 (2) | C18—H2c18 | 0.96 |
C4—C14 | 1.395 (2) | C19—C22 | 1.384 (3) |
C5—C7 | 1.538 (2) | C19—H1c19 | 0.96 |
C5—C23 | 1.524 (2) | C20—H1c20 | 0.96 |
C5—H1c5 | 0.96 | C20—H2c20 | 0.96 |
C6—C12 | 1.390 (2) | C21—H1c21 | 0.96 |
C7—C20 | 1.525 (3) | C21—H2c21 | 0.96 |
C7—H1c7 | 0.96 | C21—H3c21 | 0.96 |
C7—H2c7 | 0.96 | C22—H1c22 | 0.96 |
C8—C11 | 1.511 (2) | C23—H1c23 | 0.96 |
C3—O1—H1o1 | 106.0 (13) | C6—C12—H1c12 | 119.71 |
C2—O2—C15 | 116.72 (13) | C10—C12—H1c12 | 119.71 |
C6—O3—H1o3 | 101.6 (13) | O4—C13—C10 | 115.28 (15) |
C13—O4—C21 | 117.40 (14) | O4—C13—C14 | 125.39 (16) |
C11—N1—C17 | 112.27 (12) | C10—C13—C14 | 119.32 (16) |
C11—N1—C23 | 116.87 (13) | C4—C14—C13 | 120.79 (16) |
C17—N1—C23 | 102.81 (12) | C4—C14—H1c14 | 119.6 |
C5—N2—C9 | 115.42 (13) | C13—C14—H1c14 | 119.6 |
C5—N2—C17 | 106.39 (12) | O2—C15—H1c15 | 109.47 |
C9—N2—C17 | 111.24 (13) | O2—C15—H2c15 | 109.47 |
C2—C1—C8 | 120.84 (16) | O2—C15—H3c15 | 109.47 |
C2—C1—H1c1 | 119.58 | H1c15—C15—H2c15 | 109.47 |
C8—C1—H1c1 | 119.58 | H1c15—C15—H3c15 | 109.47 |
O2—C2—C1 | 123.98 (16) | H2c15—C15—H3c15 | 109.47 |
O2—C2—C19 | 116.01 (15) | C18—C16—C20 | 110.30 (14) |
C1—C2—C19 | 120.01 (16) | C18—C16—H1c16 | 109.47 |
O1—C3—C8 | 122.03 (15) | C18—C16—H2c16 | 109.47 |
O1—C3—C22 | 118.37 (15) | C20—C16—H1c16 | 109.47 |
C8—C3—C22 | 119.60 (15) | C20—C16—H2c16 | 109.47 |
C6—C4—C9 | 119.44 (14) | H1c16—C16—H2c16 | 108.63 |
C6—C4—C14 | 119.29 (15) | N1—C17—N2 | 104.22 (12) |
C9—C4—C14 | 121.26 (15) | N1—C17—H1c17 | 109.47 |
N2—C5—C7 | 109.08 (14) | N1—C17—H2c17 | 109.47 |
N2—C5—C23 | 103.65 (13) | N2—C17—H1c17 | 109.47 |
N2—C5—H1c5 | 114.64 | N2—C17—H2c17 | 109.47 |
C7—C5—C23 | 112.79 (13) | H1c17—C17—H2c17 | 114.25 |
C7—C5—H1c5 | 105.82 | C16—C18—C23 | 112.72 (15) |
C23—C5—H1c5 | 111.05 | C16—C18—H1c18 | 109.47 |
O3—C6—C4 | 121.62 (15) | C16—C18—H2c18 | 109.47 |
O3—C6—C12 | 118.85 (16) | C23—C18—H1c18 | 109.47 |
C4—C6—C12 | 119.52 (16) | C23—C18—H2c18 | 109.47 |
C5—C7—C20 | 113.00 (15) | H1c18—C18—H2c18 | 106.02 |
C5—C7—H1c7 | 109.47 | C2—C19—C22 | 119.58 (16) |
C5—C7—H2c7 | 109.47 | C2—C19—H1c19 | 120.21 |
C20—C7—H1c7 | 109.47 | C22—C19—H1c19 | 120.21 |
C20—C7—H2c7 | 109.47 | C7—C20—C16 | 110.14 (15) |
H1c7—C7—H2c7 | 105.7 | C7—C20—H1c20 | 109.47 |
C1—C8—C3 | 119.06 (15) | C7—C20—H2c20 | 109.47 |
C1—C8—C11 | 119.71 (15) | C16—C20—H1c20 | 109.47 |
C3—C8—C11 | 121.14 (15) | C16—C20—H2c20 | 109.47 |
N2—C9—C4 | 109.87 (13) | H1c20—C20—H2c20 | 108.8 |
N2—C9—H1c9 | 109.47 | O4—C21—H1c21 | 109.47 |
N2—C9—H2c9 | 109.47 | O4—C21—H2c21 | 109.47 |
C4—C9—H1c9 | 109.47 | O4—C21—H3c21 | 109.47 |
C4—C9—H2c9 | 109.47 | H1c21—C21—H2c21 | 109.47 |
H1c9—C9—H2c9 | 109.07 | H1c21—C21—H3c21 | 109.47 |
C12—C10—C13 | 120.47 (16) | H2c21—C21—H3c21 | 109.47 |
C12—C10—H1c10 | 119.76 | C3—C22—C19 | 120.89 (16) |
C13—C10—H1c10 | 119.76 | C3—C22—H1c22 | 119.56 |
N1—C11—C8 | 111.62 (14) | C19—C22—H1c22 | 119.56 |
N1—C11—H1c11 | 109.47 | N1—C23—C5 | 99.62 (13) |
N1—C11—H2c11 | 109.47 | N1—C23—C18 | 114.52 (13) |
C8—C11—H1c11 | 109.47 | N1—C23—H1c23 | 114.61 |
C8—C11—H2c11 | 109.47 | C5—C23—C18 | 114.50 (14) |
H1c11—C11—H2c11 | 107.24 | C5—C23—H1c23 | 114.63 |
C6—C12—C10 | 120.58 (17) | C18—C23—H1c23 | 99.77 |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H1o3···N2 | 0.93 (2) | 1.78 (2) | 2.6443 (19) | 154.4 (19) |
O1—H1o1···N1 | 0.93 (2) | 1.83 (2) | 2.6638 (19) | 148.8 (18) |
Experimental details
Crystal data | |
Chemical formula | C23H30N2O4 |
Mr | 398.5 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 120 |
a, b, c (Å) | 6.4135 (3), 11.4099 (6), 27.8249 (14) |
V (Å3) | 2036.15 (18) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 0.72 |
Crystal size (mm) | 0.21 × 0.13 × 0.13 |
Data collection | |
Diffractometer | Agilent Xcalibur (Atlas, Gemini ultra) |
Absorption correction | Multi-scan (CrysAlis PRO; Agilent, 2010) |
Tmin, Tmax | 0.341, 1 |
No. of measured, independent and observed [I > 3σ(I)] reflections | 5920, 3491, 3103 |
Rint | 0.023 |
(sin θ/λ)max (Å−1) | 0.597 |
Refinement | |
R[F > 3σ(F)], wR(F), S | 0.031, 0.080, 1.13 |
No. of reflections | 3491 |
No. of parameters | 269 |
No. of restraints | 1 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.11, −0.09 |
Computer programs: CrysAlis PRO (Agilent, 2010), SUPERFLIP (Palatinus & Chapuis 2007), JANA2006 (Petříček et al., 2006), Diamond (Brandenburg & Putz, 2005), JANA2006 (Petříček et al. 2006).
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H1o3···N2 | 0.93 (2) | 1.78 (2) | 2.6443 (19) | 154.4 (19) |
O1—H1o1···N1 | 0.93 (2) | 1.83 (2) | 2.6638 (19) | 148.8 (18) |
Acknowledgements
We acknowledge the Dirección de Investigaciones, Sede Bogotá (DIB) de laUniversidad Nacional de Colombia, for financial support of this work and the Praemium Academiae project of the Academy of Sciences of the Czech Republic. DQ acknowledges the Vicerrectoría Académica de la Universidad Nacional de Colombia for a fellowship.
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Structural features and stereochemistry of 1,1- and 1,2-diamine functionalities play an important role in the potential reactivity of cyclic aminals. We have demonstrated that cyclic aminals are precursors of di-Mannich bases, an interesting family of 1,2-diamines, where the lone pairs usually adopt an anti conformation (Rivera, et al. 2011) to avoid electron pair repulsions (the rabbit-ears effect) (Hutchins et al. 1968). Although a syn conformation is not typical in this kind of compounds, we obtained 4,4'-difluoro-2,2'-{[(3aR,7aS)-2,3,3a,4,5,6,7,7a-octahydro-1H-1,3-benzimidazole-1,3-diyl]bis(methylene)}diphenol (Rivera et al., 2013a), one exception of the "rabbit-ears effect" (Hutchins et al., 1968). Here we report the synthesis and crystal structure of the title compound (I).
The molecular structure and atom-numbering scheme for (I) are shown in Fig. 1. The bond lengths are close to normal (Allen et al., 1987). The crystal structure of (I) shows two intramolecular hydrogen bonds with graph-set motif S(6) (Bernstein et al., 1995) (Table 1), where the N···H distances and the N···O distances are shorter (by about 0.06 Å and 0.03 Å, respectively) than the observed values in a related structure (Rivera, et al. 2013a). These results suggest that the electronic character of the< i>para substituent in the aromatic rings does not significantly influence the strength of the intermolecular hydrogen bonds in these compounds.
The cyclohexane ring adopts a chair conformation where the endocyclic C—C—C bond angles are distorted from the normal tetrahedral bond angles in a chair conformation (Geise et al., 1971), since these values are in the range of 110.29 (15)° to 114.50 (14)°. The imidazolidine ring adopts a half chair conformation (Van den Enden & Geise, 1981), where the nitrogen lone pairs are oriented in a syn disposition and the benzyl groups are located in 1,3-diequatorial positions.
The dihedral angle between the aromatic rings is 49.19 (52) °. The C3—C8 and C6—C4 bonds are the longest and the C10—C12 and C19—C22 bond are the shortest in the aromatic rings.