organic compounds
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In the crystal structure of the title compound, C21H24F2N2O2, there are two intramolecular O—HN hydrogen bonds involving the N atoms of the imidazolidine ring and the hydroxy groups. The crystal studied was a meso compound obtained by the reaction of the aminal (2S,7R,11S,16R)-1,8,10,17-tetraazapentacyclo[8.8.1.18,17.02,7.011,16]cosane with 4-fluorophenol. The imidazolidine ring has a twisted conformation with a CH—CH—N—CH2 torsion angle of 44.99 (14)° and, surprisingly, the lone pairs of the N atoms are disposed in a syn isomerism, making the title compound an exception to the typical `rabbit-ear effect' in 1,2-diamines. In the crystal, molecules are linked via C—HF hydrogen bonds, forming chains along the c-axis direction. These chains are linked via another C—HF hydrogen bond, forming a three-dimensional network.
organic compounds
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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—HN 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.
organic compounds
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The asymmetric unit of the title compound, C23H30N2O2, contains one half-molecule, with a twofold axis splitting the molecule in two identical halves. The structure of the racemic mixture has been reported previously [Rivera et al. (2009) J. Chem. Crystallogr. 39, 827–830] but the enantiomer reported here crystallized in the orthorhombic space group P21212 (Z = 2), whereas the racemate occurs in the triclinic space group P-1 (Z = 2). The observed molecular conformation is stabilized by two intramolecular O—HN hydrogen bonds, which generate rings with graph-set motif S(6). In the crystal, molecules are linked via non-classical C—HO interactions, which stack the molecules along the b axis.
organic compounds
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The methyl-substituted imidazolidine ring of the title compound, C24H26N2O2, adopts an envelope conformation with the N atom adjacent to the methylene group as the flap. The methyl–ethylene fragment in this ring is disordered over two positions with an occupancy ratio of 0.899 (4):0.101 (4). The hydroxybenzyl groups are inclined at 71.57 (15) and 69.97 (19)° to the mean plane of major disorder component of the heterocyclic ring with an interplanar angle between the two hydroxybenzyl groups of 66.00 (5)°. The phenyl substituent approaches a nearly perpendicular orientation relative to the mean plane of the imidazolidine ring, making a dihedral angle of 75.60 (12)°. This conformation is stabilized by two intramolecular O—HN bonds, which generate S(6) ring motifs.
organic compounds
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In the title compound, C24H25ClN2O2, the 2-hydroxybenzyl substituents and the 2-chlorophenyl group occupy the sterically preferred equatorial positions, whereas the methyl group occupies the axial position. The imidazolidine ring adopts an envelope conformation with one of the N atoms adjacent to the methylene group as the flap. The chlorophenyl substituent approaches a nearly perpendicular orientation relative to the mean plane of the imidazolidine ring, making a dihedral angle of 73.44 (12)° and the Cl atom is almost coplanar with the C atom bearing the chlorophenyl substituent [Cl—C—C—C torsion angle = 1.1 (3)°]. The hydroxybenzyl groups make dihedral angles of 71.23 (15) and 69.13 (19)° with the mean plane of the heterocyclic ring. The dihedral angle between the two hydroxybenzyl groups is 69.61 (12)°. The molecular structure features two intramolecular O—HN hydrogen bonds with graph-set motif S(6) between the phenolic hydroxyl groups and N atoms.
organic compounds
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The asymmetric unit in the title compound, C24H26N2O3, comprises two independent molecules (A and B). In molecule A, the central 2-hydroxyphenyl ring is inclined to the mean plane of the major component of the imidazolidine ring by 84.52 (14)°, and by 68.08 (9) and 47.48 (9)° to the outer phenol rings. The later are inclined to one another by 66.76 (9)° and by 78.12 (14) and 80.20 (14)° to the imidazoline ring mean plane. In molecule B, the central 2-hydroxyphenyl ring is inclined to the mean plane of the imidazolidine ring by 73.64 (10)°, and by 75.60 (8) and 38.32 (9)° to the outer phenol rings. The later are inclined to one another by 69.47 (9)° and by 82.60 (10) and 64.26 (10)° to the imidazolidine ring mean plane. In each of the independent molecules, two intramolecular O—HN hydrogen bond form S(6) ring motifs. In disordered molecule A, the O—H groups of the 2-hydroxybenzyl groups are also involved in intramolecular O—HO hydrogen bonds, with the O atom of the hydroxyphenyl group acting as the acceptor. In the crystal, A molecules are linked by pairs of O—HO hydrogen bonds forming inversion dimers. These dimers are linked to the B molecules via O—HO hydrogen bonds forming double-layered slabs lying parallel to the bc plane.