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Journal articles on the topic 'Equatorial methyl group'

Author: Grafiati

Published: 5 June 2025

Last updated: 1 August 2025

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1

N, Sharmila, Nageswara Rao B, Ramana G.V., and Satyanarayana P.V.V. "13C NMR Spectroscopy: A Tool for Study of Conformational Analysis of 2-Aryl-trans-decahydroquinolin-4-ols." Caribbean Journal of Science and Technology 07, no. 01 (2019): 76–87. http://dx.doi.org/10.55434/cbi.2019.7110.

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In this investigation, proton decoupled 13C NMR Spectroscopy was used as a tool for the study of conformations of differently substituted 2-aryl-trans-decahydroquinolin-4-ols. The fusion of the rings in 2-aryl-trans-decahydroquinolin-4-ols was conclusively proved to be trans-, from a comparison of the experimental and calculated values. The signal assignments were made on the basis of the model system and in this case trans-decahydroquinoline was taken as model system. Substituent parameters for methyl, hydroxyl, and phenyl groups were derived from analogous systems and incorporated in the mod

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2

Massywestropp, RA, RA Massywestropp, ERT Tiekink, ERT Tiekink, LM Tippett, and LM Tippett. "Crystal Structure and Equilibration of 1-[(1R*,4S*)-4,5,8-Trimethyl-1,2,3,4-tetrahydronaphthalen-1-yl]ethanone, C15H20O." Australian Journal of Chemistry 46, no. 2 (1993): 239. http://dx.doi.org/10.1071/ch9930239.

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The crystal structure of 1-[(1R*,4S*)-4,5,8-trimethyl-1,2,3,4-tetrahydronaphthalen-1-yl]ethan-one showed a half-chair conformation with the methyl group pseudo-axial and the acetyl group pseudo-equatorial. Equilibration gave a trans-to-cis ratio of 5:2.

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3

Chen, Guangwu, Richard W. Franck, Guangli Yang, and Michael Blumenstein. "Anomeric effects of sulfones." Canadian Journal of Chemistry 80, no. 8 (2002): 894–99. http://dx.doi.org/10.1139/v02-095.

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The anomeric effect of the sulfone group in tetrahydropyrans has been determined. The value is >2 kcal mol1, which is larger than the A-value of a methyl group but less than the A-value of the sulfone in a tetrahydropyran. Hence, in an unsubstituted tetrahydropyranyl sulfone, the equatorial conformer predominates, whereas in a properly substituted methyltetrahydropyranyl sulfone, an axial sulfone is preferred over an axial methyl group.Key words: sulfone, tetrahydropyran, anomeric effect.

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4

Petrović, Vesna, Ivan Halasz, Srđanka Tomić та Dubravka Matković Čalogović. "Methyl 4-O-pivaloyl-β-D-xylopyranoside". Acta Crystallographica Section E Structure Reports Online 62, № 7 (2006): o2746—o2748. http://dx.doi.org/10.1107/s1600536806021052.

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The six-membered ring of the title compound, C11H20O6, adopts the chair conformation, with the 4-O-pivaloyl group in an equatorial position. Two vicinal hydroxyl groups of each molecule form four hydrogen bonds of the O—H...O type in a one-dimensional chain running along the b axis.

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5

Brecknell, Douglas J., Raymond M. Carman, Ross A. Edwards, Karl A. Hansford, Tomislav Karoli, and Ward T. Robinson. "Halogenated Terpenoids. XXIX The 1-Bromo 1-Bromomethyl Cyclohexyl System." Australian Journal of Chemistry 50, no. 7 (1997): 689. http://dx.doi.org/10.1071/c96188.

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Bromination of methylene groups exocyclic to cyclohexyl systems normally affords two isomeric products; the axial 1-bromo equatorial 1-bromomethyl compound and the axial 1-bromomethyl equatorial 1-bromo derivative. Free energy differences between these two isomers, and the conformations adopted by the axial 1-bromomethyl group, have been explored by n.m.r. spectroscopy, by X-ray crystallography and by MM3 calculations. Evidence is presented to show that the ax-bromomethyl group exists primarily as those rotamers which site the bromine atom synclinal to the vicinal bromine. The A value for a br

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6

Hiller, W., A. Castiñeiras, M. E. García- Fernandez, M. R. Bermejo, J. Bravo, and A. Sanchez. "The Crystal Structure of TlBrI2(4-methylpyridine-N-oxide)2." Zeitschrift für Naturforschung B 43, no. 1 (1988): 132–33. http://dx.doi.org/10.1515/znb-1988-0123.

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Abstract The unit cell of TlBrI2 (4-methylpyridine-N-oxide) 2 is orthorhombic, space group Pnna. with a = 1126.9(3),b = 919.8(2),c = 1210.4(3) pm.and Z = 4. The structure consists of discrete TlBrI2 (4-methyl-pyridine-N-oxide)2 molecules which have a distorted trigonal-bipyramidal geometry. The thallium atom is coordinated to two iodine atoms and a bromine atom in equatorial positions, and by two 4-methyl-pyridine-N-oxide ligands in the axial positions.

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7

Thiruvalluvar, A., and S. Ponnuswamy. "2,4,4-Trimethyl-N-phenyl-2,3,4,5-tetrahydro-1H-1,5-benzodiazepine-1-carboxamide." Acta Crystallographica Section E Structure Reports Online 63, no. 11 (2007): o4264. http://dx.doi.org/10.1107/s1600536807048519.

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In the title compound, C19H23N3O, the seven-membered diazepine ring adopts a boat conformation. The phenylcarbamoyl group is coplanar with the N atom and its two attached C atoms. The methyl group at position 2 has an equatorial orientation. The dihedral angle between the two benzene rings is 81.07 (9)°. The crystal structure is stabilized by intramolecular C—H...O and intermolecular N—H...O hydrogen bonds.

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8

Oilunkaniemi, Raija, Risto S. Laitinen та Markku Ahlgrén. "The Crystal and Molecular Structure of (μ-Oxo)bis{chloro(methyl)thienyl- tellurium(IV)}". Zeitschrift für Naturforschung B 56, № 2 (2001): 215–18. http://dx.doi.org/10.1515/znb-2001-0215.

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Abstract The formation and the crystal and molecular structure of (μ-oxo)bis{chloro(methyl)thienyl-tellurium(IV)}, [Me(Th)TeCl]20 , are described. The compound is orthorhombic, space group Pbcn, a = 1893.30(2), b = 891.96(2), c = 966.24(5) pm; Z =4. The tellurium atom shows trigonal bi-pyramidal coordination with chlorine and the bridging oxygen atoms in axial, and methyl and thienyl groups in equatorial positions. The two close intermolecular Te(1) ···Cl(1) contacts expand the coordination sphere around tellurium to an almost regular octahedron.

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9

Boczoń, Władysław, and Beata Jasiewicz. "Synthesis and Conformational Analysis of Disubstituted Sparteine Derivatives." Collection of Czechoslovak Chemical Communications 68, no. 4 (2003): 696–710. http://dx.doi.org/10.1135/cccc20030696.

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Synthesis of disubstituted sparteine derivatives and their diperchlorate salts was performed. Their IR and NMR spectra were analysed to determine the structure of these compounds, as well as the substituent and the protonation effects. It was shown that both unsaturated (2,17β-dimethyl-2,3-didehydrosparteine (12), 17β-isopropyl-2-methyl-2,3-didehydrosparteine (13)) and saturated (2,17β-dimethylsparteine (14), 17β-isopropyl-2-methylsparteine (15)) newly obtained sparteine derivatives have the same configurational-conformational system: trans A/B chair/chair, trans C/D boat/chair. The methyl and

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10

Mohandas, T., M. Velayutham Pillai, T. Vidhyasagar, A. Pasupathy, and P. Sakthivel. "Methyl ({[(4E)-1,3-dimethyl-2,6-diphenylpiperidin-4-ylidene]amino}oxy)acetate." Acta Crystallographica Section E Structure Reports Online 70, no. 5 (2014): o513. http://dx.doi.org/10.1107/s1600536814006667.

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In the title compound, C22H26N2O3, the piperidine ring exhibits a chair conformation. The phenyl rings attached to the piperidine at the 2- and 6-positions have axial orientations. These rings make a dihedral angle of 49.75 (11)°. The aminooxy acetate group attached at the 4-position has an equatorial orientation. In the crystal, inversion dimers linked by pairs of C—H...π interactions occur.

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11

Novoa de Armas, Héctor, Oswald M. Peeters, Norbert M. Blaton та ін. "9β,11β-Epoxy-3β-hydroxy-5α-androstan-17-one". Acta Crystallographica Section E Structure Reports Online 57, № 1 (2000): o39—o40. http://dx.doi.org/10.1107/s1600536800018845.

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In the title compound, C19H28O3, the ester linkage in ringAis equatorial. The six-membered ringsAandBhave chair conformations, but ringCcan be better described as a half-chair. The five-membered ringDadopts a 14α-envelope conformation. TheA/B,B/CandC/Dring junctions are alltrans. The packing of the molecules is assumed to be dictated mainly by intermolecular hydrogen bonds. There is an intramolecular C—H...O interaction between the O11 atom of the epoxy group and the methyl C18 group.

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12

Kalina, Marián, Viktor Kettmann, František Pavelčík та Jaroslav Majer. "The crystal structure of potassium ΛΔ-rac-2,3-butanediamine-N,N,N',N'-tetraacetatecobaltate hemihydrate". Collection of Czechoslovak Chemical Communications 50, № 1 (1985): 171–87. http://dx.doi.org/10.1135/cccc19850171.

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The crystal structure of ΛΔ-K [Co(rac-bdta)] . 1/2 H2O was solved by the X-ray diffraction method and refined by the least squares method to R = 0.047 on the basis of 3 847 diffraction values. The substance crystallizes in a space group with symmetry P 1 with the following lattice parameters: a = 0.9412(5), b = 1.2166(6), c = l.5370(9)nm, α = 70.68(4), β = 73.45(4), γ = 83.24(4)°. The crystal structure consists of two symmetrically independent enantiomer pairs Δ-[Co(R,R)-bdta] and Λ-[Co(S,S)-bdta]- K+ ions and molecules of water of crystallization. The Co(III) atom is octahedrally coordinated

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13

Zeller, Matthias, Jonas Warneke, and Vladimir Azov. "Relative substituent orientation in the structure ofcis-3-chloro-1,3-dimethyl-N-(4-nitrophenyl)-2-oxocyclopentane-1-carboxamide." Acta Crystallographica Section E Structure Reports Online 70, no. 9 (2014): 121–23. http://dx.doi.org/10.1107/s1600536814017711.

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The structure of the title compound, C14H15ClN2O4, prepared by reaction of a methacryloyl dimer with nitroaniline, was determined to establish the relative substituent orientation on the cyclopentanone ring. In agreement with an earlier proposed reaction mechanism, the amide group and the methyl group adjacent to the chloro substituent adopt equatorial positions and relativecisorientation, whereas the Cl substituent itself and the methyl group adjacent to the amide have axial orientations relative to the mean plane of the five-membered ring. The conformation of the molecule is stabilized by on

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14

Oishi, Takeshi, Hiroaki Yamamoto, Tomoya Sugai, et al. "Crystal structure of (±)-(7RS,8SR)-7-methyl-1,4-dioxaspiro[4.5]decane-7,8-diol." Acta Crystallographica Section E Crystallographic Communications 71, no. 10 (2015): 1181–84. http://dx.doi.org/10.1107/s2056989015016783.

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In the title compound, C9H16O4, the five-membered dioxolane ring adopts a twist conformation; two adjacent C atoms deviate alternately from the mean plane of other atoms by −0.297 (4) and 0.288 (4) Å. The spiro-fused cyclohexane ring shows a chair form. The hydroxy group substituted in an axial position makes an intramolecular O—H...O hydrogen bond with one of the O atoms in the cyclic ether, forming anS(6) ring motif. In the crystal, the O—H...O hydrogen bond involving the equatorial hydroxy group connects the molecules into a zigzag chain with aC(5) motif running along thecaxis.

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15

Essid, Manel, Houda Marouani, and Mohamed Rzaigui. "1-Methylpiperazine-1,4-dium bis(hydrogen oxalate)." Acta Crystallographica Section E Structure Reports Online 70, no. 3 (2014): o326—o327. http://dx.doi.org/10.1107/s1600536814003559.

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In the crystal structure of the title compound, C5H14N22+·2HC2O4−, the two crystallographically independent hydrogen oxalate anions are linked by strong intermolecular O—H...O hydrogen bonds, forming two independent corrugated chains parallel to thebaxis. These chains are further connected by N—H...O and C—H...O hydrogen bonds originating from the organic cations, forming a three-dimensional network. The diprotonated piperazine ring adopts a chair conformation, with the methyl group occupying an equatorial position.

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16

Hellier, D. G., P. Luger, and J. Buschmann. "Chemistry of the S=O bond. 13. Structures of isomers 1 (I) and 2 (II) of 4-methyl-1,3,2-dioxathiane 2-oxide and 1,3,2-dioxathiepane 2-oxide (III) at 256, 240 and 228 K." Acta Crystallographica Section B Structural Science 52, no. 3 (1996): 505–8. http://dx.doi.org/10.1107/s0108768195012912.

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The structures of the two isomers of 4-methyl-1,3,2-dioxathiane 2-oxide, C4H8SO3 (I, II), and 1,3,2-dioxathiepane 2-oxide, C4H8SO3 (III), have been determined by X-ray diffraction methods for single crystals that were grown in this case at low temperatures from the normally liquid compounds. Compound (I): orthorhombic, P212121, Mr = 136.17, a = 7.204 (6), b = 13.670 (11), c = 6.041 (6) Å, V = 594.91 Å3, Z= 4, Dx = 1.520 Mg m−3, Mo Kα (λ = 0.71068 Å), μ = 4.49 cm−1, F(000) = 288, T = 256 K, R = 0.042 for 778 unique reflections. Compound (II): orthorhombic, P212121, Mr = 136.17, a = 18.238 (6),

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17

Essid, Manel, Thierry Roisnel та Houda Marouani. "Bis(1-methylpiperazine-1,4-diium) di-μ-bromido-bis[tetrabromidobismuthate(III)] dihydrate". Acta Crystallographica Section E Structure Reports Online 70, № 6 (2014): m202—m203. http://dx.doi.org/10.1107/s1600536814009805.

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In the title hydrated salt, (C5H14N2)2[Bi2Br10]·2H2O, the complete [Bi2Br10]4−bioctahedron is generated by crystallographic inversion symmetry. The diprotonated piperazine ring adopts a chair conformation, with the methyl group occupying an equatorial position. In the crystal, the tetraanions and water molecules are linked by O—H...Br and O—H...(Br,Br) hydrogen bonds to generate [100] chains. The chains are crosslinked by N—H...Br, N—H...O and C—H...Br hydrogen bonds originating from the piperazinediium dications, thereby forming a three-dimensional network.

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18

Liu, He, Jingyan Wang та Bohua Zhong. "Synthesis and Crystal Structure of 17-Allyl-4,5-anhydro-7α-[(R)-1-hydroxy-1-methyl-3-(2-thienyl)propyl]-6-methoxy-6,14-ethanomorphinan-3,4,5-triol". Collection of Czechoslovak Chemical Communications 70, № 2 (2005): 237–46. http://dx.doi.org/10.1135/cccc20050237.

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17-Allyl-4,5-anhydro-7α-[(R)-1-hydroxy-1-methyl-3-(2-thienyl)propyl]-6-methoxy-6,14-ethanomorphinan-3,4,5-triol (thienorphine 6) was synthesized and structurally characterized by NMR spectra, ESI-MS and X-ray diffraction. The crystal structure indicates that thienorphine maintained the main rigid structure of morphine while containing the C6-C14 ethano bridge. The allyl group is located in the equatorial position as expected. The packing diagram of 6 showed the presence of intramolecular and intermolecular O-H···O hydrogen bonds linking the molecules into a zigzag infinite quasi-one-dimensiona

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19

Herdtweck, Eberhardt, Paul Kiprof, Wolfgang A. Herrmann, Josef G. Kuchler, and Ian Degnan. "Mehrfachbindungen zwischen Hauptgruppenelementen und Übergangsmetallen, LXXIX. / Multiple Bonds between Main Group Elements and Transition Metals, LXXIX." Zeitschrift für Naturforschung B 45, no. 7 (1990): 937–42. http://dx.doi.org/10.1515/znb-1990-0703.

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Trimethylstannyl perrhenate, (CH3)3SnOReO3 (2), synthesized from dirheniumheptoxide and tetramethyltin, has a zigzag-chain crystal structure. This structure originates from catenation of individual molecules via the tin atom to a perrhenate group of another molecule. The tin atom thus forms the center of a trigonal-bipyramidal coordination geometry, with two oxygen atoms adopting apical positions while three methyl groups define the equatorial plane. The Re—O—Sn bonds alternate between linear and slightly bent. The zigzag-aggregation of the chain-structure results from the tetrahedral [ReO4] s

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20

Li, Yunli, Zhanjun Li, Yanjie Hu, and Wen Li. "Crystal structure of 1-[(1S,2R)-2-hydroxy-1-methyl-2-phenylethyl]pyrrolidinium 2-amino-5-chlorobenzoate." Acta Crystallographica Section E Crystallographic Communications 71, no. 8 (2015): o584—o585. http://dx.doi.org/10.1107/s2056989015013389.

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In the cation of the title molecular salt, C13H20NO+·C7H5ClNO2−, the five-membered ring adopts a twisted conformation about one of the C—N bonds. The exocyclic N—C bond has an equatorial orientation. The dihedral angle between the five-membered ring (all atoms) and the benzene ring is 76.56 (19)°. In the anion, the dihedral angle between the carboxylate group and the benzene ring is 18.57 (14)°, and an intramolecular N—H...O hydrogen bond closes anS(6) ring. In the crystal, the components are linked by O—H...O and N—H...O hydrogen bonds, generating [100] chains.

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21

Lysenko, Andrey B., Oleg V. Shishkin, and Rostislav D. Lampeka. "Synthesis and Structure of a Palladium(II) Chloride Complex with 2-(2-Methyl-3-phenyl-isoxazolidin-5-yl)-pyridine." Zeitschrift für Naturforschung B 55, no. 5 (2000): 373–76. http://dx.doi.org/10.1515/znb-2000-0505.

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The 1:1 complex of palladium(II) chloride with 2-(2-methyl-3-phenyl-isoxazolidin-5-yl)- pyridine (L) has been prepared and studied by means of elemental analysis, 1H NMR spectroscopy and X-ray diffraction (monoclinic, space group P21/n with parameters: a = 8.141(2), b = 9.750(2),c = 20.691(6)Å ,β = 95.62(3)°,V = 1634.4(7)Å3 ,Z = 4 ;R1= 0.054 and wR2= 0.144 for 3352 unique reflections). A square-planar coordination polyhedron has been established for the palladium atom both in acetone solution and in the solid state. The organic ligand is coordinated toometal in a bidentate manner via nitrogen

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22

Kamaraj, A., R. Rajkumar, K. Krishnasamy, and S. Murugavel. "Crystal structure of methyl 2-[2,4-bis(4-fluorophenyl)-3-azabicyclo[3.3.1]nonan-9-ylidene]hydrazinecarboxylate." Acta Crystallographica Section E Structure Reports Online 70, no. 9 (2014): 145–47. http://dx.doi.org/10.1107/s1600536814018935.

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In the title compound, C22H23F2N3O2, the bicyclic ring system exists in a twin-chair conformation with an equatorial disposition of the 4-fluorophenyl groups on the heterocycle. These aromatic rings are inclined to one another by 19.4 (1)°. In the crystal, molecules are linked by pairs of N—H...O and C—H...O hydrogen bonds into inversion dimers, incorporatingR12(7) andR22(8) ring motifs; the same O atom accepts both hydrogen bonds. These dimers are further linked by a pair of C—H...F hydrogen bonds, enclosingR22(28) ring motifs, forming supramolecular chains along [010]. The NH group of the py

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23

Van, Vinh, Wolfgang Stahl, Minh Tuyen Nguyen, and Ha Vinh Lam Nguyen. "The smell of coffee: the carbon atom microwave structure of coffee furanone validated by quantum chemistry." Canadian Journal of Physics 98, no. 6 (2020): 538–42. http://dx.doi.org/10.1139/cjp-2019-0475.

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The rotational spectra of coffee furanone (2-methyltetrahydrofuran-3-one) have been measured in the frequency range from 2.0 to 26.5 GHz using a molecular jet Fourier transform microwave spectrometer. Quantum chemical calculations used for the conformational analysis yielded two stable twist conformers, which were described using the Cremer–Pople notation for five-membered rings. The experimental spectrum of the more stable conformer with the methyl group in equatorial position was assigned and fitted using a rigid rotor model with centrifugal distortion corrections. The spectra of all five 13

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24

Parimala, Sowmianarayanan, та Parasuraman Selvam. "Crystal structure of aquadioxido(2-{[(2-oxidoethyl)imino]methyl}phenolato-κ3O,N,O′)molybdenum(VI)". Acta Crystallographica Section E Crystallographic Communications 71, № 2 (2015): m35—m36. http://dx.doi.org/10.1107/s2056989015001231.

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The mononuclear title complex, [Mo(C9H9NO2)O2(H2O)], contains an Mo(VI) atom in a distorted octahedral coordination sphere defined by an Mo=O and an Mo—(OH2) bond to the axial ligands and two Mo—O bonds to phenolate and alcoholate O atoms, another Mo=O bond and one Mo—N bond to the imino N atom in the equatorial plane. The five-membered metalla-ring shows an envelope conformation. In the crystal, individual molecules are connected into a layered arrangement parallel to (100) by means of O—H...O hydrogen bonds involving the water molecule as a donor group and the O atoms of neighbouring complex

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25

Vlad, P. F., N. D. Ungur, A. N. Aricu та I. Yu Andreeva. "Regioselective dehydration of axial and equatorial tertiary alcohols with α-methyl group in the cyclohexane ring by Swern’s reagent". Russian Chemical Bulletin 46, № 4 (1997): 767–70. http://dx.doi.org/10.1007/bf02495210.

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26

Baurmeister, J., A. Franken, and W. Preetz. "Darstellung, 11B-NMR- und Schwingungsspektren mehrfach alkylierter closo-Hexaborate und Kristallstruktur von cis- und trans-[P(C6H5)4][B6H5(CH3)2] sowie mer-[P(C6H5)4][B6H4(CH3)3] / Preparation, 11B NMR and Vibrational Spectra of Multialkylated Hexaborates and Crystal Structures of cis- and trans-[P(C6H5)4][B6H5(CH3)2] and mer-[P(C6H5)4][B6H4(CH3)3]." Zeitschrift für Naturforschung B 50, no. 5 (1995): 772–80. http://dx.doi.org/10.1515/znb-1995-0515.

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Abstract By treatment of protonated monoalkyl-closo-hexaborates [B6H6R]-. R = CH3, C2H5, n-C3H7, i-C3H7 in aqueous alkaline solution with [As(C6H5)4]Cl the yellow orange deprotonated tetraphenylarsonium salts are precipitated, which react with methyl iodide or ethyl iodide to give dialkylated and protonated B6-compounds. The cisltrans isomers formed in a 1:1 ratio have been separated by ion exchange chromatography on diethylam inoethyl cellulose. Repeated deprotonation and reaction with methyl iodide affords mer-[B6H4 (CH3)3]-. The crystal structures of cis-[P(C6H5)4][B6H5(CH3)2] (I), trans-[P

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27

Maloney, Sarah, Alexandra M. Z. Slawin, and J. Derek Woollins. "2,2-Dimethyl-2,3-dihydro-1H-perimidine." Acta Crystallographica Section E Structure Reports Online 69, no. 2 (2013): o246. http://dx.doi.org/10.1107/s1600536813000986.

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The title compound, C13H14N2, was obtained from reaction of diaminonaphthalene with acetone. In both independent molecules in the asymmetric unit, the tricyclic perimidine consists of a planar (r.m.s. deviations = 0.0125 and 0.0181 Å) naphthalene ring system and an envelope conformation C4N2ringwith the NCN group hinged with respect to the naphthalene backbone by 36.9 (2) and 41.3 (2)° in the two independent molecules. The methyl substituents are arranged approximately axial and equatorial on the apical C atom. In the crystal, one of the N—H groups of one independent molecule is involved in cl

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28

Puddephatt, Richard J. "Selectivity in carbon–carbon coupling reactions at palladium(IV) and platinum(IV)." Canadian Journal of Chemistry 97, no. 7 (2019): 529–37. http://dx.doi.org/10.1139/cjc-2019-0015.

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The isomerization and reductive elimination reactions from octahedral organometallic complexes of palladium(IV) and platinum(IV) usually occur through five-coordinate intermediates that cannot be directly detected. This paper reports a computational study of five-coordinate complexes of formulae [PtMe3(bipy)]+, [PtMe2Ph(bipy)]+, and [PtMe(CH2CMe2C6H4)(bipy)]+ (M = Pd or Pt, bipy = 2,2′-bipyridine), particularly with respect to reactivity and selectivity in reductive elimination. All of the complexes are predicted to have square pyramidal structures with the bipy and two R groups in the equator

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29

Pocinho, Alexandre, Carine Duhayon, Emmanuel Gras та Christelle Hureau. "Crystal structure of catena-poly[[[dichloridocopper(II)]-{μ-tert-butyl N-methyl-N-[4-(6-{[4-(pyridin-2-yl-κN)-1H-1,2,3-triazol-1-yl-κN 3]methyl}-1,3-benzothiazol-2-yl)phenyl]carbamato}] acetonitrile monosolvate]". Acta Crystallographica Section E Crystallographic Communications 74, № 2 (2018): 158–62. http://dx.doi.org/10.1107/s2056989018000488.

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In the title coordination polymer, {[CuCl2(C27H26N6O2S)]·CH3CN} n , the copper(II) ion is fivefold coordinated, with an almost perfect square-pyramidal coordination sphere. In the equatorial plane, it is ligated to a pyridine N atom and an N atom of the triazole unit and to two Cl− ions, while the apical position is occupied by the carbonyl O atom of the tert-butyl carbamate group. In the crystal, the polymer chains propagate in the [11-1] direction, with the acetonitrile solvent molecules linked to the chain by C—H...N hydrogen bonds. The chains are linked by C—H...Cl hydrogen bonds forming s

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30

Gul, Waseem, Ahmed Galal, Mahmoud A. ElSohly, and Paulo Carvalho. "Crystal structure of (9S,10S)-10-ethoxy-9-hydroxy-6,6,9-trimethyl-3-pentyl-7,8,9,10-tetrahydro-6H-benzo[c]chromen-1-yl 4-methylbenzenesulfonate." Acta Crystallographica Section E Crystallographic Communications 71, no. 12 (2015): o1082—o1083. http://dx.doi.org/10.1107/s2056989015024044.

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In the structure of the title compound, C30H40O6S, the cyclohexene and heterocyclic rings are linked by a double bond. The cyclohexene ring has a half-chair conformation (the methylene group adjacent to the hydroxy substituent lies above the remaining atoms) and the hydroxy and ethoxy groups have equatorial and bisectional dispositions, respectively. The heterocyclic ring has an envelope conformation (with the CMe2C atom being the flap). The dihedral angle between the aromatic rings is 53.88 (10)°. A long intramolecular C—H...S interaction is noted. In the molecular packing, hydroxy-O—H...O(su

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31

Pegg, GG, and GV Meehan. "Substituent Rate Effects in Sigmatropic Homodienyl [1,5]-Hydrogen Migrations." Australian Journal of Chemistry 43, no. 8 (1990): 1357. http://dx.doi.org/10.1071/ch9901357.

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The small but systematic polar substituent effect on the rates of [1,5]- homodienyl hydrogen migrations previously observed for the series of alkenylcyclopropane substrates (1) has been further explored through two additional substrate series (4) and (6) bearing the aryl probe at C4 and at the migration origin C1 respectively. However, negligible substituent effects were apparent at these positions. It now seems that the substituent effect originally observed at C5 reflects electronic perturbation by the substituent, rather than an inherent charge separation in the transition state for homodie

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32

Dallasta Pedroso, Sofia, Ignez Caracelli, Julio Zukerman-Schpector, et al. "1-Ethyl 2-methyl 3,4-bis(acetyloxy)pyrrolidine-1,2-dicarboxylate: crystal structure, Hirshfeld surface analysis and computational chemistry." Acta Crystallographica Section E Crystallographic Communications 76, no. 6 (2020): 967–72. http://dx.doi.org/10.1107/s205698902000701x.

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The title compound, C13H19NO8, is based on a tetra-substituted pyrrolidine ring, which has a twisted conformation about the central C—C bond; the Cm—Ca—Ca—Cme torsion angle is 38.26 (15)° [m = methylcarboxylate, a = acetyloxy and me = methylene]. While the N-bound ethylcarboxylate group occupies an equatorial position, the remaining substituents occupy axial positions. In the crystal, supramolecular double-layers are formed by weak methyl- and methylene-C—H...O(carbonyl) interactions involving all four carbonyl-O atoms. The two-dimensional arrays stack along the c axis without directional inte

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33

Bernát, Juraj, Ladislav Kniežo, Gabriela Birošová, et al. "Reactions of PO(NCS)3 with 4-Hydroxy-1,3-dioxanes. Crystal Structure of rel-(2S,4R,5S,6S)-2,6-Diethyl-5-methyl-4-(N'-benzylthioureido)-1,3-dioxane." Collection of Czechoslovak Chemical Communications 57, no. 6 (1992): 1299–313. http://dx.doi.org/10.1135/cccc19921299.

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Substituted 4-hydroxy-1,3-dioxanes II react rapidly with PO(NCS)3 to give 4-isothiocyanato-1,3-dioxanes III. The 1H NMR spectra showed that in the isothiocyanate IIIa the predominant stereoisomer has its NCS group in axial position. The addition of benzylamine to the isothiocyanates IIIa and IIIb gave uniform thioureas IVa and IVb with equatorial alkyl groups at 2 and 6 positions and axial thioureido group at 4 position. On the other hand, the isothiocyanate IIIc reacts with benzylamine to give a mixture of three stereoisomeric thioureas V,VI, and VIII. The structure of VI was proved by means

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34

Fraser-Reid, B., J. C. Lopez, G. nair Anilkumar, et al. "Evidence for Efficient Unpromoted Regioselective Reactions of Vicinal and Non-Vicinal Diols." Australian Journal of Chemistry 55, no. 2 (2002): 123. http://dx.doi.org/10.1071/ch01146.

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A 1965 publication from Angyal's laboratory reported that the cis-vicinal diol group of tetra-O-benzyl myo-inositol reacted regioselectively, sometimes exclusively, with acylating agents at the equatorial OH, but with alkylating agents at the axial OH. Recent reports by Fraser-Reid and coworkers showed that such selectivities were also found for the trans-1,3-diol of tetra-O-benzyl myo-inositol, as well as the C2-C4 hydroxyls of a di-O-allyl mannopyranoside. In addition, the latter workers reported that regioselectivities could be extended to glycosidation reactions. Thus, n-pentenyl ortho est

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35

Hughes, Claire, Adele L. Chuck, Suzanne M. Turner, and Peter S. Liss. "Methyl and ethyl nitrate saturation anomalies in the Southern Ocean (36 - 65°S, 30 - 70°W)." Environmental Chemistry 5, no. 1 (2008): 11. http://dx.doi.org/10.1071/en07083.

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Environmental Context. The alkyl nitrates are a group of organic compounds that are known to be produced naturally in seawater. The sea-to-air flux of alkyl nitrates is believed to contribute significantly to the ‘odd nitrogen’ reservoir of the atmosphere and to play an important role in regulating tropospheric ozone levels in remote marine regions. Here we expand our knowledge of alkyl nitrate concentration distributions and saturation anomalies to Southern Ocean waters. Abstract. We report the first coupled atmosphere and seawater alkyl nitrate measurements for the Southern Ocean in the area

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36

Del Vigo, Enrique A., Carlos A. Stortz, and Carla Marino. "Regioselectivity of glycosylation reactions of galactose acceptors: an experimental and theoretical study." Beilstein Journal of Organic Chemistry 15 (December 19, 2019): 2982–89. http://dx.doi.org/10.3762/bjoc.15.294.

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Regioselective glycosylations allow planning simpler strategies for the synthesis of oligosaccharides, and thus reducing the need of using protecting groups. With the idea of gaining further understanding of such regioselectivity, we analyzed the relative reactivity of the OH-3 and OH-4 groups of 2,6-diprotected methyl α- and β-galactopyranoside derivatives in glycosylation reactions. The glycosyl acceptors were efficiently prepared by simple methodologies, and glycosyl donors with different reactivities were assessed. High regioselectivities were achieved in favor of the 1→3 products due to t

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37

Acosta Quintero, Lina M., Alirio Palma, Justo Cobo, and Christopher Glidewell. "Six polycyclic pyrimidoazepine derivatives: syntheses, molecular structures and supramolecular assembly." Acta Crystallographica Section C Structural Chemistry 72, no. 4 (2016): 346–57. http://dx.doi.org/10.1107/s2053229616004654.

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A versatile synthetic method has been developed for the formation of variously substituted polycyclic pyrimidoazepine derivatives, formed by nucleophilic substitution reactions on the corresponding chloro-substituted compounds; the reactions can be promoted either by conventional heating in basic solutions or by microwave heating in solvent-free systems. Thus, (6RS)-6,11-dimethyl-3,5,6,11-tetrahydro-4H-benzo[b]pyrimido[5,4-f]azepin-4-one, C14H15N3O, (I), was isolated from a solution containing (6RS)-4-chloro-8-hydroxy-6,11-dimethyl-6,11-dihydro-5H-benzo[b]pyrimido[5,4-f]azepine and benzene-1,2

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38

Anh, Le Tuan, Alexander A. Titov, Maxim S. Kobzev, et al. "Unusual thermolysis of azacyclic allene under microwave conditions: crystal structure of (3RS,3aSR,8RS,8aRS)-methyl 5,6-dimethoxy-3a,10-dimethyl-1-phenyl-3,3a,8,8a-tetrahydro-3,8-(epiminomethano)cyclopenta[a]indene-2-carboxylate from synchrotron X-ray diffraction." Acta Crystallographica Section E Crystallographic Communications 73, no. 11 (2017): 1770–73. http://dx.doi.org/10.1107/s2056989017014864.

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The title compound, C25H27NO4(I), the product of the unusual thermolysis of azacyclic allene methyl 10,11-dimethoxy-3,8-dimethyl-6-phenyl-3-azabenzo[d]cyclodeca-4,6,7-triene-5-carboxylate, represents a bicyclic heterosystem and crystallizes in the monoclinic space groupP21/cwith three crystallographically independent molecules in the unit cell. These independent molecules adopt very similar geometries and differ only in the conformations of the two methoxy substituents on the benzene ring. In two of the three independent molecules, both methoxy groups are almost coplanar with the benzene ring

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39

Chowdhury, S. A., and S. C. Bhattacharjee. "In Silico Biological Profile Prediction of Some Selectively Synthesized Acyl Rhamnopyranosides." Journal of Scientific Research 13, no. 2 (2021): 657–68. http://dx.doi.org/10.3329/jsr.v13i2.50581.

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Over the past several decades significant biological activities including brains protective and antimicrobial activities have made sugar esters (SEs) as a topic of great interest. In this context, unimolar 3-chlorobenzoylation of methyl α-L-rhamnopyranoside (4) using dibutyltin oxide method regioselectively furnished only the 3-O-substitution product 5 in excellent yield. The reaction proceeded via the formation of a cyclic 2,3-O-dibutylstannylene intermediate where equatorial hydroxyl group is activated by the tin atom leading to the formation of product 5 only. To get biologically important

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40

Turgunov, Kambarali Kuchkarovich, Dilfuza Kadirova, Rasul Okmanov, Salima Fazilovna Aripova, and Bakhodir Tashkhodjaev. "Stereochemistry of tropane alkaloid of convolvine and their derivatives." European Journal of Chemistry 10, no. 4 (2019): 376–80. http://dx.doi.org/10.5155/eurjchem.10.4.376-380.1909.

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Structures of alkaloid convolvine (1) isolated from Convolvulus subhirsutus and its derivatives-convolamine(N-methylconvolvine) (2) and hydrochloride of N-benzylconvolvine (3) have been determined by single crystal X-ray diffraction technique. Compounds were crystallized in monoclinic space groups having four molecules in unit cell. All compounds contain a bicyclic ring system of tropane, where piperidine rings in all case adopt chair conformation. Hydrogen atom and methyl- and benzyl-substituents located in nitrogen atom of studied compounds occupy equatorial positions. The substituent of tro

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41

Brzezinski, Krzysztof, Ryszard Lazny, Aneta Nodzewska, and Katarzyna Sidorowicz. "Relative configuration, absolute configuration and absolute structure of three isomeric 8-benzyl-2-[(4-bromophenyl)(hydroxy)methyl]-8-azabicyclo[3.2.1]octan-3-ones." Acta Crystallographica Section C Crystal Structure Communications 69, no. 3 (2013): 303–6. http://dx.doi.org/10.1107/s0108270113002503.

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The title compounds, C21H22BrNO2, are isomeric 8-benzyl-2-[(4-bromophenyl)(hydroxy)methyl]-8-azabicyclo[3.2.1]octan-3-ones. Compound (I), the (±)-exo,syn-(1RS,2SR,5SR,9SR) isomer, crystallizes in the hexagonal space groupR\overline{3}, while compounds (II) [the (+)-exo,anti-(1R,2S,5S,9R) isomer] and (III) [the (±)-exo,anti-(1RS,2SR,5SR,9RS) isomer] crystallize in the orthorhombic space groupsP212121andPna21, respectively. The absolute configuration was determined for enantiomerically pure (II). For the noncentrosymmetric crystal of (III), its absolute structure was established. In the crystal

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42

Broeders, Niek L. H. L., Arthur P. van der Heiden, Leo H. Koole, Jan A. Kanters, and Arie Schouten. "2′-O-Methyl-cis-adenosine 3′,5′-cyclic methyl monophosphate, a new model system for cAMP. Aspects of structure and reactivity." Canadian Journal of Chemistry 71, no. 6 (1993): 855–63. http://dx.doi.org/10.1139/v93-114.

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This study is focussed on 2′-O-methyl-cis-adenosine 3′,5′-cyclic methyl monophosphate (cis-4; cis describes the relationship between OMe (bound to phosphorus) and the adenine base), which is regarded a model for enzyme-bound cyclic adenosine monophosphate (cAMP). In this complex the negative phosphate charge is shielded in part via complexation with cationic sites on the enzyme surface. We report synthesis, crystal structure, solution conformation (400 MHz 1H NMR), and kinetic-mechanistic aspects of the alkaline hydrolysis of cis-4. The methanol solvate of cis-4 crystallizes in the orthorhombi

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43

VLAD, P. F., N. D. UNGUR, A. N. ARYKU та I. YU ANDREEVA. "ChemInform Abstract: Regioselective Dehydration of Axial and Equatorial Tertiary Alcohols with an α-Methyl Group in the Cyclohexane Ring by Swern′s Reagent." ChemInform 28, № 39 (2010): no. http://dx.doi.org/10.1002/chin.199739075.

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44

Hadni, Hanine, Charif EL M'Barki, Mohamed Mazigh, and Menana Elhallaoui. "DFT-based QSAR studies and Molecular Docking of 1-Phenylcyclohexylamine Analogues as anticonvulsant of NMDA Receptor." Mediterranean Journal of Chemistry 9, no. 5 (2019): 390–402. http://dx.doi.org/10.13171/mjc01912121044hh.

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The phencyclidine (PCP) and their analogues have been reported to exhibit inhibitory activities toward the N-methyl-D-aspartate receptor (NMDAR). To discover the QSAR between structure of PCP derivatives and Ki activities we have used density functional theory (DFT) to generate quantum descriptors, multiple regression linear (MLR) method was applied to establish QSAR model, and an artificial neural network (ANN), considering the relevant descriptors obtained with the MLR method is explored, a correlation coefficient of RANN = 0.912 was obtained with 6-4-1 ANN model. This model is tested by usi

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45

Liang, Hong, Micheline MacKay, T. Bruce Grindley, Katherine N. Robertson, and T. Stanley Cameron. "Configurations and conformations of glycosyl sulfoxides." Canadian Journal of Chemistry 88, no. 11 (2010): 1154–74. http://dx.doi.org/10.1139/v10-091.

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X-ray crystallographic studies of two axial glycosyl sulfoxides having RS configurations (derivatives of phenyl 2-azido-2-deoxy-1-thio-α-d-galactopyranoside S-oxide) show that they adopt anti conformations in the solid state, in contrast to previous observations and assumptions. Density functional theory (DFT) calculations at the B3lYP6–311G+(d,p)/6–31G(d) level confirm that anti conformations of both phenyl and methyl RS glycosyl sulfoxides of 2-azido-2-deoxy-α-d-pyranosides are more stable than exo-anomeric conformations in the gas phase. 1D NOE measurements indicate that the more polar exo-

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46

Eryanti, Yum, Adel Zamri, Tati Herlina, Unang Supratman, Mohd Mustaqim Rosli, and Hoong-Kun Fun. "Crystal structures of 3,5-bis[(E)-3-hydroxybenzylidene]-1-methylpiperidin-4-one and 3,5-bis[(E)-2-chlorobenzylidene]-1-methylpiperidin-4-one." Acta Crystallographica Section E Crystallographic Communications 71, no. 12 (2015): 1488–92. http://dx.doi.org/10.1107/s2056989015020976.

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The title compounds, C20H19NO3, (1), and C20H17Cl2NO, (2), are the 3-hydroxybenzylidene and 2-chlorobenzylidene derivatives, respectively, of curcumin [systematic name: (1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione]. The dihedral angles between the benzene rings in each compound are 21.07 (6)° for (1) and 13.4 (3)° for (2). In both compounds, the piperidinone rings adopt a sofa confirmation and the methyl group attached to the N atom is in an equatorial position. In the crystal of (1), two pairs of O—H...N and O—H...O hydrogen bonds link the molecules, forming chains alon

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47

Ingold, K. U., and J. C. Walton. "Cycloalkylmethyl radicals. 2. Axial and equatorial cyclohexylmethyl and (4-alkylcyclohexy)methyl radicals. First determination of the conformational free energy difference of the CH2.cntdot. group." Journal of the American Chemical Society 107, no. 22 (1985): 6315–17. http://dx.doi.org/10.1021/ja00308a026.

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48

Neverov, Alexei A., Theresa L. Muise, and R. S. Brown. "X+ transfer from the halonium ions of adamantylideneadamantane to acceptor olefins. The possibility of chiral induction in the transfer process." Canadian Journal of Chemistry 75, no. 12 (1997): 1844–50. http://dx.doi.org/10.1139/v97-617.

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The bromonium ion of adamantylideneadamantane (Ad=Ad-Br+) has been used to induce the bromocyclization of a 4-pentenyl glycoside (10) and a 5-hexenyl glycoside (11) in dichloroethane. The kinetics of these processes have been studied at 25 °C in the presence of varying [Ad=Ad] and, in the case of the transfer to 10, in the presence of pentanol. The second-order rate constants for bromocyclization of these two alkenes are (1.04 ± 0.06) × 10−1 M−1 s−1 and (5.34 ± 0.2) × 10−1 M−1 s−1, respectively, and in no case does added Ad=Ad or pentanol alter the reaction rate. The kinetic behavior is interp

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49

Sunitha Kumari, M., M. Harish Kumar, D. V. Deevith, H. C. Devarajegowda, and B. S. Palakshamurthy. "Crystal structure, Hirshfeld surface, DFT, molecular docking of 1-[(6-tert-butyl-2-oxo-2H-chromen-4-yl)methyl]-4,4-dimethylpiperidine-2,6-dione and cytotoxic effects on breast cancer (MDA-MB 231), human alveolar basal epithelial (A549) cell lines." Acta Crystallographica Section E Crystallographic Communications 81, no. 3 (2025): 257–63. https://doi.org/10.1107/s2056989025001550.

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The title compound, C21H25NO4, was synthesized by SN2 reaction of bromomethyl coumarin with 4,4-dimethylpiperidine-2,6-dione. The molecule crystalizes in the monoclinic system with space group C2/c. The coumarin unit is almost planar with a dihedral angle between the aromatic rings of 0.81 (2)° and an r.m.s deviation of 0.042 Å. The piperidine ring adopts a chair conformation with the two methyl groups, one methyl group occupying an axial position and the other an equatorial position, exhibiting maximum stability. In the crystal, C—H...O interactions lead to the formation of head-to-head dimer

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50

Radics, L., S. Bottka та J. Tomasz. "9-(6-Deoxy- β -D-Allofuranosyl)Adenine Cyclic 3′,5′ -Phosphor-Amidate: A New Cyclic AMP Amide Derivative Containing an Equatorial Methyl Group at the 5′-Position". Nucleosides and Nucleotides 8, № 7 (1989): 1305–17. http://dx.doi.org/10.1080/07328318908054335.

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