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1.  1,3-Bis(3-tert-butyl-2-hy­droxy-5-meth­oxy­benz­yl)hexa­hydro­pyrimidin-5-ol monohydrate 
The asymmetric unit of the title compound, C28H42N2O5·H2O, consists of one half of the organic mol­ecule and one half-mol­ecule of water, both of which are located on a mirror plane which passes through the central C atoms and the hydroxyl group of the heterocyclic system. The hydroxyl group at the central ring is disordered over two equally occupied positions. The six-membered ring adopts a chair conformation, and the 2-hy­droxy­benzyl substituents occupy the sterically preferred equatorial positions. The aromatic rings make dihedral angles of 75.57 (9)° with the mean plane of the heterocyclic ring. The dihedral angle between the two aromatic rings is 19.18 (10)°. The mol­ecular structure features two intra­molecular phenolic O—H⋯N hydrogen bonds with graph-set motif S(6). In the crystal, mol­ecules are connected via O—H⋯O hydrogen bonds into zigzag chains running along the a-axis direction.
doi:10.1107/S1600536814010769
PMCID: PMC4051104  PMID: 24940265
2.  Redetermination of 1,3,6,8-tetra­aza­tri­cyclo­[4.4.1.13,8]dodeca­ne 
The structure of the title compound, C8H16N4, which consists of four fused seven-membered rings, has been redetermined at 173 K. This redetermination corrects the orientation of two H atoms, which were located at unrealistic positions in the original room-temperature study [Murray-Rust (1974 ▶). J. Chem. Soc. Perkin Trans. 2, pp. 1136–1141]. The complete mol­ecule is generated by -42m symmetry, with one quarter of a mol­ecule [one N atom (site symmetry m), two C atoms (one with site symmetry m and the other with site symmetry 2) and two H atoms] in the asymmetric unit. No directional inter­actions beyond van der Waals contacts are apparent in the crystal structure.
doi:10.1107/S1600536814002608
PMCID: PMC3998434  PMID: 24764981
3.  6,6′-Dimethyl-2,2′-[imidazolidine-1,3-diyl­bis(methyl­ene)]diphenol 
In the title compound, C19H24N2O2, a di-Mannich base derived from 2-methyl­phenol and 1,3,6,8-tetra­aza­tri­cyclo­[4.4.1.13,8]dodecane, the imidazolidine ring adopts a twist conformation, with a twist about the ring N—C bond [C—N—C—C torsion angle = −44.34 (14)°]. The two 2-hy­droxy-3-methyl­benzyl groups are located in trans positions with respect to the imidazolidine fragment. The structure displays two intra­molecular O—H⋯N hydrogen bonds, which each form an S(6) ring motif. In the crystal, the mol­ecules are linked by weak C—H⋯O inter­actions with a bifurcated acceptor, forming a three-dimensional network.
doi:10.1107/S1600536814002128
PMCID: PMC3998388  PMID: 24764964
4.  2-[(1H-Benzimidazol-1-yl)meth­yl]phenol benzene hemisolvate 
In the title solvate, C14H12N2O·0.5C6H6, the complete benzene molecule is generated by a crystallographic inversion centre. The dihedral angle between the planes of the benzimidazole moiety and the phenol substituent is 75.28 (3)°. In the crystal, O—H⋯N hydrogen bonds link the mol­ecules into parallel chains propagating along [100]. The mol­ecules are further connected by C—H⋯π inter­actions.
doi:10.1107/S1600536814000841
PMCID: PMC3998331  PMID: 24764892
5.  2,2′-{[2-(2-Hy­droxy­phen­yl)-4-methyl­imidazolidine-1,3-di­yl]bis­(methyl­ene)}diphenol 
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—H⋯N 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—H⋯O 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—H⋯O hydrogen bonds forming inversion dimers. These dimers are linked to the B molecules via O—H⋯O hydrogen bonds forming double-layered slabs lying parallel to the bc plane.
doi:10.1107/S1600536813019417
PMCID: PMC3793786  PMID: 24109373
6.  2,2′-{[2-(2-Chloro­phen­yl)-4-methyl­imidazolidine-1,3-di­yl]bis­(methyl­ene)}diphenol 
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—H⋯N hydrogen bonds with graph-set motif S(6) between the phenolic hydroxyl groups and N atoms.
doi:10.1107/S1600536813017923
PMCID: PMC3793727  PMID: 24109314
7.  2,2′-[(4-Methyl-2-phenyl­imidazolidine-1,3-di­yl)bis­(methyl­ene)]diphenol 
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—H⋯N bonds, which generate S(6) ring motifs.
doi:10.1107/S1600536813017893
PMCID: PMC3793710  PMID: 24109297
8.  4,4′-Di-tert-butyl-2,2′-[imidazolidine-1,3-diylbis(methyl­ene)]diphenol 
In the title compound, C25H36N2O2, the two tert-butyl-substituted benzene rings are inclined at an angle of 53.5 (3)° to one another. The imidazolidine ring has an envelope conformation with with one of the C atoms of the ethylene fragment as the flap. The structure displays two intra­molecular O—H⋯N hydrogen bonds that generate S(6) ring motifs. The crystal studied was a non-merohedral twin with a fractional contribution of 0.281(6) for the minor domain.
doi:10.1107/S1600536813017157
PMCID: PMC3770425  PMID: 24046710
9.  Single-step synthesis of a new series of meso di-Mannich bases from the cyclic aminal (2S,7R,11S,16R)-1,8,10,17-tetraazapentacyclo[8.8.1.1.8,170.2,7011,16]icosane and p-substituted phenols 
Background
The results presented herein show that the cyclic aminal (2S,7R,11S,16R)-1,8,10,17-tetraazapentacyclo[8.8.1.1.8,170.2,7011,16]icosane (6), derived from cis-(meso)-1,2-diaminocyclohexane and formaldehyde, is a suitable substrate for the preption of a series of cis-meso Mannich bases such as 8a-l by reaction with p-substituted phenols 7a-l in basic media. These compounds are valuable synthetic products and may find application in asymmetric catalysis.
Results
The products were characterized principally by NMR and IR spectroscopy. Both the benzylic and aminalic protons of the perhydrobenzimidazolidine moiety were diastereotopic due to the presence of stereogenic nitrogen centers. The occurrence of intramolecular hydrogen bonding interactions was confirmed by the broad OH stretching vibration band in the IR spectra. Vibrational spectra were calculated using B3LYP at 6-31G(d,p) level, and the calculated frequencies for the νOH vibrations were compared to those of the experimental spectra. Hydrogen bonding interactions in the solid state were observed through the X-ray crystallography of 8j. Additionally, Mulliken charges and Fukui indices for 6 were calculated as theoretical descriptors of electrophilicity.
Conclusion
A new series of meso Mannich bases called 4,4′-disubstituted-2,2′-{[(3aR,7aS)-2,3,3a,4,5,6,7,7a-octahydro-1H-1,3-benzimidazole-1,3-diyl]bis(methylene)} diphenols (8a-l) which are derived from cis-(meso)-1,2-diaminocyclohexane, were obtained from cyclic aminal 6. These results confirmed the behavior of 6 as an electrophilic preformed reagent in Mannich reactions in basic media.
doi:10.1186/1752-153X-7-100
PMCID: PMC3698105  PMID: 23758899
10.  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 
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.
doi:10.1107/S1600536813015092
PMCID: PMC3772488  PMID: 24046631
11.  4,4′-Dimethyl-2,2′-{[2,3,3a,4,5,6,7,7a-octa­hydro-1H-benzimidazole-1,3-di­yl]bis­(methyl­ene)}diphenol 
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—H⋯N hydrogen bonds, which generate rings with graph-set motif S(6). In the crystal, mol­ecules are linked via non-classical C—H⋯O inter­actions, which stack the mol­ecules along the b axis.
doi:10.1107/S1600536813015237
PMCID: PMC3772489  PMID: 24046632
12.  meso-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 
In the crystal structure of the title compound, C21H24F2N2O2, there are two intra­molecular O—H⋯N 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—H⋯F hydrogen bonds, forming chains along the c-axis direction. These chains are linked via another C—H⋯F hydrogen bond, forming a three-dimensional network.
doi:10.1107/S1600536813000305
PMCID: PMC3569752  PMID: 23424498
13.  1,3-Dibenzyl-2-(2-chloro­phen­yl)-4-methyl­imidazolidine 
In the title compound, C24H25ClN2, the methine, methyl­ene and methyl C atoms of the methyl-substituted imidazolidine ring are disordered over two sets of sites with a refined occupancy ratio of 0.834 (4):0.166 (4). Each disordered ring assumes an envelope conformation with an N atom as the flap. The pendant benzyl rings are oriented equatorially with respect to the imidazolidine ring. The chloro­phenyl ring is inclined to the mean plane of the four planar atoms of the major component of the imidazolidine ring by 76.27 (12)°. The dihedral angles between the chloro­phenyl ring and the two benzyl rings are 55.31 (9) and 57.50 (8)°; the dihedral angle between these latter rings is 71.59 (9)°. In the crystal, mol­ecules are linked by C—H⋯Cl inter­actions and a number of weak C—H⋯π inter­actions, involving all three aromatic rings, forming a three-dimensional structure.
doi:10.1107/S1600536812047575
PMCID: PMC3589010  PMID: 23476246
14.  2,2′-[1,2-Phenyl­enebis(aza­nedi­yl)]di­aceto­nitrile 
The title compound, C10H10N4, shows chemical but not crystallographic C 2 symmetry. The two cyano­methyl groups are located in an anti position with respect to the aromatic ring. In the crystal, mol­ecules form parallel ladder-like tapes linked through two N—H⋯N hydrogen bonds. Further weak intra­molecular N—H⋯N hydrogen bonding is responsible for the elongation of one of the Caromatic—N bonds.
doi:10.1107/S1600536812047538
PMCID: PMC3589011  PMID: 23476247
15.  4,4′-Dimethyl-2,2′-[imidazolidine-1,3-diylbis(methyl­ene)]diphenol 
The imidazolidine ring in the title compound, C19H24N2O2, adopts a twist conformation and its mean plane (r.m.s. deviation = 0.19 Å) makes dihedral angles of 72.38 (9) and 71.64 (9)° with the two pendant aromatic rings. The dihedral angle between the phenyl rings is 55.94 (8)°. The mol­ecular structure shows the presence of two intra­molecular O—H⋯N hydrogen bonds between the phenolic hydroxyl groups and N atoms with graph-set motif S(6). In the crystal, C—H⋯O hydrogen bonds lead to the formation of chains along the b-axis direction.
doi:10.1107/S1600536812042808
PMCID: PMC3515265  PMID: 23284485
16.  (2S,7S)-10-Ethyl-1,8,10,12-tetra­aza­tetra­cyclo­[8.3.1.18,12.02,7]penta­decan-10-ium iodide 
The title chiral quaternary ammonium salt, C13H25N4 +·I−, was synthesized through the Menschutkin reaction between the cage aminal (2S,7S)-1,8,10,12-tetra­aza­tetra­cyclo­[8.3.1.18,12.02,7]penta­decane and ethyl iodide. The quaternization occurred regioselectively on the nitrogen with major sp3 character. The crystal structure consists of anions and cations separated by normal distances. Ions are not linked through C—H⋯I hydrogen bonds.
doi:10.1107/S1600536812040159
PMCID: PMC3470393  PMID: 23125806
17.  4,4′-Difluoro-2,2′-[imidazolidine-1,3-diylbis(methyl­ene)]diphenol 
In the title compound, C17H18F2N2O2, the imidazolidine ring system exists in a twist conformation. The mean plane through this ring system forms dihedral angles of 80.8 (8)° and 66.2 (13)°, with the benzene rings. The dihedral angle between the benzene rings is 52.0 (14)°. Two intra­molecular O—H⋯N hydrogen bonds each generate S(6) ring motifs. In the crystal, weak C—H⋯O hydrogen bonds form dimers, which are connected by further C—H⋯O inter­actions.
doi:10.1107/S1600536812040329
PMCID: PMC3470394  PMID: 23125807
18.  rac-4-Chloro-2-[({2-[(3-chloro-6-hy­droxy-2,4-dimethyl­benz­yl)(meth­yl)amino]­prop­yl}(meth­yl)amino)­meth­yl]-3,5-dimethyl­phenol 
The title compound, C23H32Cl2N2O2, a potential chiral ligand for coordination chemistry, was prepared by a two-step reaction. The mol­ecule is located on a crystallographic centre of inversion. As a result, the methyl group bonded to the methyl­ene group is disordered over two equally occupied positions, sharing the same site as the H atom of the chiral C atom. As a further consequence of the crystallographic centrosymmetry, the 1,2-diamino­propane unit adopts an anti­periplanar conformation and the two benzene rings are coplanar. The central chain is in an all-trans arrangement. An intra­molecular O—H⋯N hydrogen bond makes an S(6) ring motif. A C—H⋯π inter­action links the mol­ecules into one-dimensional chains along the [001] direction.
doi:10.1107/S1600536812039694
PMCID: PMC3470356  PMID: 23125769
19.  3,3′-(Ethane-1,2-diyl)bis(6-meth­oxy-3,4-dihydro-2H-1,3-benzoxazine) mono­hydrate 
The asymmetric unit of the title compound, C20H24N2O4·H2O, contains one half-organic mol­ecule (an inversion centre generates the other half of the mol­ecule) and a half-mol­ecule of water (the O atom has site symmetry 2). The near planarity of the fused-benzene ring is illustrated by the very small deviations of all the atoms from the plane [largest deviation = 0.0092 (11) Å. The six-membered N,O-containing ring adopts a half-chair conformation. The observed N—CH2 and CH2—O bond lengths can be correlated to the manifestation of an anomeric effect in the N—CH2—O unit. In the crystal, the mol­ecules are connected into zigzag chains parallel to [001] through O—H⋯N hydrogen bonds formed between the oxazinic N atom and the solvent water mol­ecule. The chains are consolidated by C—H⋯O inter­actions.
doi:10.1107/S1600536812035519
PMCID: PMC3435746  PMID: 22969617
20.  1,3-Dinitro­soimidazolidine 
The title compound, C3H6N4O2, exhibits partial disorder with the refined occupancy ratios of the two components being 0.582 (5):0.418 (5). In the major component, the nitroso groups have a relative syn spatial arrangement [O=N⋯N=O pseudo-torsion angle = 1.1 (4)°], whereas the other component has an anti disposition [177.6 (1)°]. The N—N=O moieties are almost coplanar with a dihedral angle of 5.3 (3)°, while in the minor occupied set of atoms, this angle is 8 (1)°. In both components, the imidazolidine ring adopts a twisted conformation on the C—C bond and the crystal structure shows the strain of this ring according to the N—CH2—CH2—N torsion angles [25.9 (5) and −23.8 (7)°]. In the crystal, molecules are linked by weak C—H⋯O hydrogen bonds.
doi:10.1107/S1600536812030796
PMCID: PMC3414354  PMID: 22904887
21.  6H,13H-5,12:7,14-Dimethano­dinaphtho­[2,3-d:2,3-i][1,3,6,8]tetra­azecine 
In the title compound, C24H20N4, obtained through the condensation of naphthalene-2,3-diamine with formaldehyde in methanol, the mol­ecule is located on a special position of site symmetry -4. Due to symmetry considerations, the aromatic rings are strictly perpendicular to each other. In the crystal, mol­ecules are linked by pairs of C—H⋯π inter­actions into columns along [110].
doi:10.1107/S1600536812010185
PMCID: PMC3344019  PMID: 22589928
22.  6,6′-Dimethyl-2,2′-[1,3-diazinane-1,3-diyl­bis(methyl­ene)]diphenol 
In the mol­ecule of the title compound, C20H26N2O2, the 1,3-diazinane ring adopts a slightly distorted chair conformation and the hy­droxy­benzyl substituents occupy equatorial positions on the N atoms of the heterocyclic ring. There are two intra­molecular O—H⋯N hydrogen bonds between the N atoms of the 1,3-diazinane ring and the hy­droxy groups of the aromatic rings, with an S(6) set-graph motif. However, the two observed intra­molecular hydrogen-bond distances were different. Considering that both N atoms experience the same chemical environment, it is surprising to see the difference in O⋯N distances [2.6771 (14) and 2.8123 (12) Å]. The crystal structure is further stabilized by a C—H⋯π interaction.
doi:10.1107/S1600536812005284
PMCID: PMC3295478  PMID: 22412589
23.  (1H-Benzimidazol-1-yl)methanol 
In the title compound, C8H8N2O, the N—CH2 and CH2—O bond lengths can be correlated to the manifestation of an anomeric effect in the N—CH2—O moiety. In the crystal, inter­molecular O—H⋯N hydrogen bonds link the mol­ecules into zigzag chains, with graph-set motif C(6), parallel to [001]. These chains are further linked into sheets by weak nonclassical C—H⋯O hydrogen bonds.
doi:10.1107/S1600536812004114
PMCID: PMC3295415  PMID: 22412526
24.  2,2′-[1,3-Diazinane-1,3-diylbis(methyl­ene)]bis­(4-bromo­phenol) 
The title compound, C18H20Br2N2O2, the heterocyclic ring adopts a chair conformation. The benzene rings make dihedral angles of 86.84 (10) and 60.73 (10)° with the mean plane of the heterocyclic ring. The dihedral angle between the two benzene rings is 79.77 (10)°. The mol­ecular structure is stabilized by two intra­molecular hydrogen bonds between the phenolic hy­droxy groups and N atoms with graph-set motif S(6). The crystal structure is stabilized by weak C—H⋯π inter­actions.
doi:10.1107/S1600536812001985
PMCID: PMC3275243  PMID: 22347099
25.  1,1′-[Imidazolidine-1,3-diylbis(methyl­ene)]bis­(1H-benzotriazole) 
In the title compound, C17H18N8, the imidazolidine ring adopts an envelope conformation with the substituents at the N atoms in trans positions with respect to the central ring. The dihedral angle between the two benzotriazole rings is 71.65 (10)°. In the crystal, non-classical C—H⋯N inter­actions link the mol­ecules into helical chains along the b axis. The crystal packing is further stabilized by weak C—H⋯π inter­actions.
doi:10.1107/S1600536812000232
PMCID: PMC3275003  PMID: 22346948

Results 1-25 (54)