Crystal structures of two chiral piperidine derivatives: 1-[(1 R )-2-hydroxy-1-phenylethyl]piperidin-4-one and 8-[(1 S )-1-phenylethyl]-1,4-dioxa-8-azaspiro[4.5]decane-7-thione (original) (raw)
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Journal of Molecular Structure, 2008
In continuation of the studies on weak H-bond formation in N-substituted-spiro-succinimides, the crystal structures of three derivatives from the series of N-methyl-arylpiperazine-spiro-succinimides were examined. Previously and newly studied species differ in the lengths of the distance between imide and aromatic rings. In the described structures methyl-piperazine is located as an aliphatic linker in the place of one atomic group (CH 2 ). It was established that the distance elongation destroyed supramolecular synthons formed in previously studied N-benzyl-spiro-succinimides. The molecules of N-methyl-arylpiperazine-spiro-succinimides are joined predominantly in dimmers via two types of weak H-bonds: C@O. . .HAC(sp 3 ) and C@O. . .HAC(arom). In the bonds with Csp 3 piperazine carbon atoms are mainly involved.
Acta crystallographica. Section E, Crystallographic communications, 2015
As part of a comprehensive program to discover α9α10 nicotinic acetyl-choline receptor antagonists, the title compounds C30H36N2, (I), and C36H48N2, (II), were synthesized by coupling 4,4'-bis-(3-bromo-prop-1-yn-1-yl)-1,1'-biphenyl with 4-methyl-piperidine and 2,2,6,6-tetra-methyl-piperidine, respectively, in aceto-nitrile at room temperature. In compound (I), the biphenyl system has a twisted conformation with a dihedral angle of 26.57 (6)° between the two phenyl rings of the biphenyl moiety, while in compound (II), the biphenyl moiety sits on a crystallographic inversion centre so the two phenyl rings are exactly coplanar. The terminal piperidine rings in both compound (I) and compound (II) are in the chair conformation. In compound (I), the dihedral angles about the ethynyl groups between the planes of the phenyl rings and the piperidine ring N atoms are 37.16 (16) and 14.20 (17)°. In compound (II), the corresponding dihedral angles are both 61.48 (17)°. There are no note...
Zeitschrift für Kristallographie - Crystalline Materials, 2018
Crystallography reveals two polymorphs for the salt [4-(4-acetylphenyl)piperazin-1-ium][2-amino-4-nitrobenzoate], a monoclinic form (2; modelled as P21/n with Z′=4) formed directly from the reaction mixture, and a triclinic form (1; Z′=1) isolated from recrystallisation. Relatively minor differences are noted in the conformations of the anions and of the cations, mainly relating to the twist of, respectively, the carboxylate groups and piperazin-1-ium rings with respect to the phenyl rings they are connected to. The key feature of the packing of both forms is the formation of charge-assisted ammonium-N–H···O (carboxylate) hydrogen bonds which lead to cyclic 12-membered {···HNH ···OCO}2 synthons in the case of 1 but, supramolecular chains in 2. The three-dimensional architecture in the crystal of 1 is further stabilised by amine-N–H···O (nitro) and amine-N–H···O (acetyl) hydrogen bonds, leading to double-layers in the bc-plane, which are linked along the a-axis by methylene-C–H···O (...
ChemistrySelect, 2017
Weak noncovalent interactions between large disclike molecules in poorly solvating media generally lead to the formation of fibers where the molecules stack atop one another. Here, we show that a particular chiral spacing group between large aromatic moieties, which usually lead to columnar stacks, in this case gives rise to an intramolecularly folded structure in relatively polar solvents, but in very apolar solvents forms finite aggregates. The molecule that displays this behavior has a C 3 symmetric benzene-1,3,5-tris(3,3′diamido-2,2′-bipyridine) (BTAB) core with three metalloporphyrin units appended to it through short chiral spacers. Quite well-defined chromophore arrangements are evident by circular dichroism (CD) spectroscopy of this compound in solution, where clear exciton coupled bands of porphyrins are observed. In more polar solvents where the molecules are dispersed, a relatively weak CD signal is observed as a result of intramolecular folding, a feature confirmed by molecular modeling. The intramolecular folding was confirmed by measuring the CD of a C 2 symmetric analogue. The C 3 symmetric BTAB cores that would normally be expected to stack in a chiral arrangement in apolar solvents show no indication of CD, suggesting that there is no transfer of chirality through it (although the expected planar conformation of the 2,2′-bipyridine unit is confirmed by NMR spectroscopy). The incorporation of the porphyrins on the 3,3′-diamino-2,2′-bipyridine moiety spaced by a chiral unit leaves the latter incapable of assembling through supramolecular π−π stacking. Rather, modeling indicates that the three metalloporphyrin units interact, thanks to van der Waals interactions, favoring their close interactions over that of the BTAB units. Atomic force microscopy shows that, in contrast to other examples of molecules with the same core, disclike aggregates (rather than fibrillar one dimensional aggregates) are favored by the C 3 symmetric molecule. The closed structures are formed through nondirectional interlocking of porphyrin rings. The chiral spacer between the rigid core and the porphyrin moieties is undoubtedly important in determining the outcome in polar or less polar solvents, as modeling shows that this joint in the molecule has two favored conformations that render the molecule relatively flat or convex.
SUPRAMOLECULAR CHEMISTRY Principles of molecular associations and organizations as exemplified in biological macromolecules like nucleic acids, proteins and enzymes. Synthetic molecular receptors: receptors with molecular cleft, molecular tweezers, receptors with multiple hydrogen sites. Structures and properties of crown ethers, cryptands, cyclophanes, calixarenes, rotaxanes and cyclodextrins. Synthesis of crown ethers, cryptands and calixarenes. Molecular recognition and catalysis, molecular self-assembly. Supramolecular Polymers, Gelsand Fibres.
2011
In the present study 1,2-bis(4-pyridyl)ethane (BPA) crystallizes with 2-chlorobenzoic acid (2CBA), 4methylbenzoic acid (4MBA), phthalic acid (PA), succinic acid (SA) and adipic acid (AA) to yield co-crystals BPA.2CBA (1), BPA.4MBA (2), BPA.PA (3), BPA.SA (4) and BPA.AA (5) respectively. All the five co-crystals are constituted by the utilization of the R 2 2 (7) synthon, created by the combination of hard N-HÁ Á ÁO and complementary soft C-HÁ Á ÁO hydrogen bonds. 1 and 2 illustrate the formation of three component aggregate as in both cases BPA interacts with carboxylic acids to form supramolecular ladder-type assembies. Molecular recognition in co-crystals 3-5 results in the formation of extended infinite tapes and differ further as a consequence of the soft C-HÁ Á ÁO bonds and stacking interactions. Structure 3 shows the formation of zigzag tapes while 4 and 5 form linear infinite tapes. Structure 4 shows isostructural behaviour with an analogous structure previously reported (Bowes et al. (2003) [77]).The isostructurality is because of the structural resemblance between both the entities in the co-crystals-fumaric acid/succinic acid and 1,2-bis(4-pyridyl)ethane/1,2-bis(4-pyridyl)ethene. Compound 5 shows good degree of resemblance with another reported analogous structure-1,2-bis(4-pyridyl)ethene adipic acid. (Zhang et al. (2003) [72]). Structure 5 and the reported structure form similar supramolecular sheets through intertape interactions differing from each other only in the alignment of neighboring tapes. The linear tapes in both the cases are linked laterally through different C-HÁ Á ÁO interactions and ventrally through different stacking interactions. This work illustrates the construction of different supramolecular architectures and the role of weak C-HÁ Á ÁO hydrogen bonds and stacking interactions in the higher level of supramolecular organization.
Structures of Three Chalcones Derived from 6-Methoxy-2-naphthaldehyde
Journal of Chemical Crystallography, 2009
In the molecular structures of three new structurally related chalcone derivatives, namely (2E)-1-(2hydroxyphenyl)-3-(6-methoxy-2-naphthyl)prop-2-en-1-one, C 20 H 16 O 3 , I, (2E)-1-(2-chloropyridin-4-yl)-3-(6-methoxy-2-naphthyl)prop-2-en-1-one, C 19 H 14 ClNO 2 , II, and (2E)-3-(6-methoxy-2-naphthyl)-1-pyridin-4-ylprop-2-en-1-one, III, C 19 H 15 NO 2 , the configuration of the keto group is syn with respect to the olefinic double bond. In all three structures the molecules pack with weak intermolecular C-HÁÁÁO interactions utilizing both the methoxy and keto oxygen's in I, the methoxy oxygen in II and the keto oxygen in III. These interactions link the molecules into chains diagonally along the (011) plane of the unit cell in I and III and along the (010) plane in II. The dihedral angle between the phenyl and 2-napthyl rings in I is 31.7(3)°. In II and III the dihedral angle between the pyridyl and 2-naphthyl rings is 14.4(9)°a nd 1.8(9)°, respectively. C-HÁÁÁO hydrogen bonding interactions influence these twist angles of these rings in I-III while weak p-p stacking interactions between naphthyl rings in I and III and also between pyridyl and naphthyl rings in II help stabilize crystal packing. [I: P2 1 /c, a = 7.6635(4) Å , b = 11.8047(6) Å , c = 16.7584 Å , b = 99.271(5)°, V = 1496.25(13) Å 3 ; II: Pbca, a = 14.1424(4) Å , b = 6.0957(2) Å , c = 33.1458(11) Å , V = 2857.43(16) Å 3 ; III: P2 1 /c, a = 11.5155(4) Å , b = 6.0020(2) Å , c = 22.4645(8) Å , b = 103.002(4)°, V = 1512.85(9) Å 3 ].
Zeitschrift für Kristallographie - New Crystal Structures, 2002
C32H26N2O, monoclinic, P12,/nl (No. 14), a = 9.146(1) Â, b= 11.463(3) Â, c = 23.423(5) Â, β = 95.49(2)°, V = 2444.5 Â 3 , Z = 4,p m = 1.216 gem" 3 , Rp(F) = 0.038, wRKf(F 2) = 0.125, 7=293 K. Source of material The title compound has been synthesized as described in [ 1 ]. Details of the synthesis will be published elsewhere. Tiny plate like crystals of the compound were grown from chloroform-ethanol solution by slow evaporation. Discussion 2-Pyridine class of compounds show a wide spectrum of biological activities and also found to adopt an interesting stereochemistry. To investigate the effect of the substituents of different sizes like dimethyl [2], diethyl [3], dibenzyl [present study] at 1,3 position of the tetrahydropyridine (THP), on the molecular conformation of THP, we report here the molecular structure of one of the series of such steriochemically interesting THP derivative, namely 1,3-dibenzyl-2-oxo-4,6-diphenyl-1,2,3,4-tetrahydropyridine-3-carbonitrUe. THP ring plane has a half-chair conformation with two of its carbon atoms C2 and C3 deviated maximum by-0.329(1) Â and 0.269(1) Â, respectively from the best plane of the THP ring. Distorted half-chair conformation adopted by THP ring has also been observed for other closely related compounds [2-4]. Both the benzyl groups and the phenyl rings are planar within themselves. Benzyl group C26-C32 at Ν1 and the phenyl ring at para position of N1 stand vertical (dihedral angle is 87.92(5)° and 89.61(5)°, respectively) with the THP ring plane whereas the benzyl group and the phenyl ring at meta and ortho positions of Ν1 are twisted out of the central THP ring by 34.90(7)° and 49.20(6)°, respectively. The marked difference in the dihedral angle appeared to be influenced by their positions on THP ring. The displacement of C19 and C20 atoms of benzyl groups by-1.885(6) Â and-2.557(8) Â, respectively, on the same side from the central THP ring are significant. C-Ν bond 1.137(2) Â and the angle C2-C18-N2 of 175.1 (2)° of the cyano moiety have characteristic values as commonly observed in 3-cyano 2-pyridine derivatives [2,3,5]. Torsional angleCl-C2-C18-N2of-164(2)° defines the coplanar conformation of cyano moiety with THP ring plane. As observed in other pyridine derivatives Ol is remarkably out [6,7] of the best plane (0.53(1) Â) of the central ring. The torsion angles about C2-C18 and C2-C19 bonds (with the values for 1,3-diethyl and 1,3-dimethyl inside the square bracket) are: ¿C1-C2-C18-N2 =-164(2)° [-126(8)°, 107(5)°], ¿C3-C2-C18-N2 = 74(2)° [113(8)°,-136(5)°], ¿C1-C2-C19-C20 = 47.49(2)° [55.2(4)°,-], ZC3-C2-C19-C20 = 169.21(4)° [179.4(3)°,-]. The drastic difference in the values of torsion angles reveals that the molecular conformation of THP is quite different in all the three compounds. Thus these observations suggest that the size of the substituent influence the molecular