Synthesis and Structure of the Potassium Salt with Monodeprotonated 1,2,3-Tri(ethoxycarbonylpropyl)-p-t-butylcalix[6]arene

2008 ◽  
Vol 61 (7) ◽  
pp. 537 ◽  
Author(s):  
Ze-Bao Zheng ◽  
Ren-Tao Wu ◽  
Ji-Kun Li ◽  
Yi-Feng Sun
Keyword(s):  
Potassium Salt ◽  
Crystallographic Analysis ◽  
Potassium Ion ◽  
High Yield ◽  
Cone Conformation ◽  
X Ray ◽  
Partial Cone ◽  
Phenyl Rings ◽  
Close Contacts

Alkylation of p-t-butylcalix[6]arene with ethyl 4-bromobutanoate in the presence of K2CO3 results in a potassium salt of the monodeprotonated 1,2,3-tri(ethoxycarbonylpropyl)-p-t-butylcalix[6]arene in high yield. X-Ray crystallographic analysis shows that this compound exists as a double partial cone conformation. The potassium ion is positioned near the centre of the cavity of the macrocycle and binds to four phenolic oxygens. Close contacts between the potassium ion and phenyl rings observed in this compound are indicative of the presence of the cation–π interaction. The molecules are connected via intermolecular K+···O interactions into infinite chains.

scholarly journals Attempted Synthesis and Unexpected β-Fragmentation of a Hindered β-Keto Nitroxide

2017 ◽  
Vol 70 (10) ◽  
pp. 1106 ◽  
Author(s):  
Chris Edwards ◽  
Peter C. Healy ◽  
W. Ken Busfield ◽  
Ezio Rizzardo ◽  
San H. Thang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ring Opening ◽  
Sodium Tungstate ◽  
Crystallographic Analysis ◽  
High Yield ◽  
Fragmentation Mechanism ◽  
Pentanoic Acid ◽  
X Ray ◽  
Ring Opening Reaction

The attempted synthesis of a β-keto imidazolidinone nitroxide by oxidation of the β-hydroxy imidazolidinone precursor with hydrogen peroxide and sodium tungstate led to an unexpected ring-opening reaction to produce 1,4-diazaspiro[4.5]dec-1-en-3-oxo-2-pentanoic acid 1-oxide (13) in high yield. The structure of 13 was confirmed by X-ray crystallographic analysis. A β-fragmentation mechanism is suggested for the oxidative ring-opening reaction.

The direct electrochemical synthesis of thiolato complexes of cobalt and nickel, and the crystal structure of bis(phenylthiolato)bis(1,10-phenanthroline)cobalt(III) perchlorate

1988 ◽  
Vol 66 (9) ◽  
pp. 2151-2156 ◽  
Author(s):  
Raj K. Chadha ◽  
Rajesh Kumar ◽  
Jaime Romero Lopez-Grado ◽  
Dennis G. Tuck
Keyword(s):  
Crystal Structure ◽  
Electrochemical Oxidation ◽  
Electrochemical Synthesis ◽  
Crystallographic Analysis ◽  
High Yield ◽  
X Ray ◽  
Metal Anode ◽  
Aerial Oxidation ◽  
Perchlorate Salt ◽  
Cobalt And Nickel

Cobalt(II) and nickel(II) thiolates, M(SR)2, can be prepared in high yield by the electrochemical oxidation of a metal anode in an acetonitrile or acetone solution of RSH (R = C6H5, o-CH3C6H4, 2-C10H7, 2,3,4,5-C6F4H; not all combinations). When 2,2-bipyridine or 1,10-phenanthroline (=L) is added to the electrolyte phase, the products are the adducts M(SR)2L2. In the case of Co(SC6H5)2(phen)2, aerial oxidation leads to the formation of the cobalt(III) cation [Co(SC6H5)2(phen)2]+, isolated as the perchlorate salt. X-ray crystallographic analysis showed that this cation has a cis-CoS2(N2)2 kernel.

scholarly journals Synthesis of Some Biologically Important 3-Oxacepham Derivatives

1970 ◽  
Vol 5 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Mohammad Rafiqul Islam ◽  
Mohammad Nurnabi ◽  
AM Sarwaruddin Chowdhury ◽  
Mohammad Mehdi Masud
Keyword(s):  
Key Words ◽  
Full Text ◽  
Crystallographic Analysis ◽  
High Yield ◽  
Methyl Group ◽  
X Ray ◽  
Tert Butyl ◽  
Relative Stereochemistry

The 6H-oxathiazines 1a-e having imine moiety underwent [2+2] cycloaddition with phenoxyacetylchloride in the presence of Et3N to give β-lactam derivatives 2a-e in high yield. The X-ray crystallographic analysis revealed the relative stereochemistry that the substituents at C-2 and C-4 were cis configurated. The subtituents at C-6 and C-7 were also cis to each other. However, the 6H-oxathiazines 1f-i containing tert-butyl or methyl group at C-4 did not undergo the cycloaddition. Key words: Azetedinone, β-lactam, oxacepham, cycloaddition, imine, ketene, oxathiazine. Dhaka Univ. J. Pharm. Sci. Vol.5(1-2) 2006 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website

Metal Ion Binding to Calixarenes: Pendent Arm Coordination Assisted by Self-Inclusion

1994 ◽  
Vol 47 (6) ◽  
pp. 1185 ◽  
Author(s):  
JM Harrowfield ◽  
M Mocerino ◽  
BW Skelton ◽  
CR Whitaker ◽  
AH White
Keyword(s):  
Structural Characterization ◽  
Metal Ion ◽  
Room Temperature ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
Cone Conformation ◽  
X Ray ◽  
Partial Cone ◽  
Arm Coordination

The synthesis and room-temperature single-crystal X-ray structural characterization of 25,27- di(allyloxy)-5,17-di-t-butyl-26,28-dimethoxycalix[4]arene are recorded. Crystals are monoclinic, C2/c, a 29.089(5), b 10.742(2), c 26.218(8) Ǻ, β 110.09(2)°, Z = 8; the structure was refined to a residual of 0.065 for 4103 independent 'observed' [I > 3σ(I)] reflections. The flattened partial cone conformation of the molecule allows inclusion of one of the methoxy substituents in a way which could block inclusion of a metal ion capable of polyhapto aromatic coordination and which may therefore explain why solution n.m.r. measurements indicate that silver(I) binds to the pendent alkene groups.

Dihydropyridines in synthesis and biosynthesis. III. Coupling of dihydropyridinetricarbonylchromium(0) complexes: bipyridyls

1982 ◽  
Vol 60 (3) ◽  
pp. 323-326 ◽  
Author(s):  
James P. Kutney ◽  
Lucas Kaczmarek ◽  
Danuta Mostowicz ◽  
Brian R. Worth
Keyword(s):  
Low Temperature ◽  
Crystallographic Analysis ◽  
High Yield ◽  
X Ray ◽  
Methyl Pyridine

Reaction of 1,2- and 1,6-dihydro-3-ethyl-N-methyl pyridine tricarbonylchromium(0) complexes with methyllithium at low temperature afforded a high yield of dimeric tricarbonylchromium(0) complexes. Structures of the latter products were established by X-ray crystallographic analysis. Some chemistry of these novel compounds is described.

β-octabromo-meso-tris(pentafluorophenyl)corrole: reductive demetalation-based synthesis of a heretofore inaccessible, perhalogenated free-base corrole

2010 ◽  
Vol 14 (06) ◽  
pp. 509-512 ◽  
Author(s):  
Can Capar ◽  
Lars-Kristian Hansen ◽  
Jeanet Conradie ◽  
Abhik Ghosh
Keyword(s):  
Copper Complex ◽  
Free Ligand ◽  
Crystallographic Analysis ◽  
The Other ◽  
High Yield ◽  
Free Base ◽  
X Ray ◽  
The Mean

Long known in various metal-complexed forms, β-octabromo-meso-tris(pentafluorophenyl)corrole, H3[Br8TPFPC ], has not been available as a free ligand until now. It can be prepared in high yield (86%) via reductive demetalation (conc. H2SO4 , FeCl2 ) of Mn[Br8TPFPC ]. Interestingly, the same conditions did not result in demetalation of the analogous copper complex, which may be contrasted to the behavior of many other copper corroles, which demetalate cleanly. X-ray crystallographic analysis revealed a unique "half-saddled" conformation, wherein two of the pyrrole rings on one side of the direct pyrrole-pyrrole linkage are strongly tilted up and down relative to each other, whereas the other two pyrrole rings are roughly in the mean plane of the macrocycle.

scholarly journals Crystal structure of potassium hydrogen bis((E)-2-{4-[3-(thiophen-3-yl)acryloyl]phenoxy}acetate)

2021 ◽  
Vol 77 (6) ◽  
pp. 609-614
Author(s):  
Trung Vu Quoc ◽  
Linh Phan Thuy ◽  
Dai Do Ba ◽  
Duong Tran Thi Thuy ◽  
Linh Nguyen Ngoc ◽  
...  
Keyword(s):  
Spectroscopic Data ◽  
Potassium Salt ◽  
Potassium Ion ◽  
Hirshfeld Surface ◽  
Carboxyl Groups ◽  
Water Mixture ◽  
Asymmetric Unit ◽  
Compound C ◽  
Phenyl Rings ◽  
Potassium Hydrogen

The synthesis and spectroscopic data of (E)-2-{4-[3-(thiophen-3-yl)acryloyl]phenoxy}acetic acid are described. Crystallization from an ethanol–water mixture resulted in the title compound, C30H23KO8S2 or [K(C15H11O4S)(C15H12O4S)] n , containing one molecule of the acid and one molecule of the potassium salt in the asymmetric unit. Both molecules share the H atom between their carboxyl groups and a potassium ion. The C=C bonds display an E configuration. The thiophene and phenyl rings in the two molecules are inclined by 43.3 (2) and 22.7 (2)°. The potassium ion is octahedrally coordinated by six O atoms. This distorted octahedron shares on opposite sides two oxygen atoms with inversion-related octahedra, resulting in chains of octahedra running in the [010] direction, which form ladder-like chains by C—H...π interactions. A Hirshfeld surface analysis indicates that the highest contributions to the surface contacts arise from interactions in which H atoms are involved, with the most important contribution being from H...H (31.6 and 31.9% for the two molecules) interactions.

Quaternary structure of Limulus polyphemus hemocyanin

1978 ◽  
Vol 36 (2) ◽  
pp. 176-177
Author(s):  
T. Wichertjes ◽  
E.J. Kwak ◽  
E.F.J. Van Bruggen
Keyword(s):  
Electron Microscopy ◽  
Functional Properties ◽  
Horseshoe Crab ◽  
Temperature Jump ◽  
Quaternary Structure ◽  
Crystallographic Analysis ◽  
Limulus Polyphemus ◽  
Oxygen Binding ◽  
X Ray ◽  
Intact Molecule

Hemocyanin of the horseshoe crab (Limulus polyphemus) has been studied in nany ways. Recently the structure, dissociation and reassembly was studied using electron microscopy of negatively stained specimens as the method of investigation. Crystallization of the protein proved to be possible and X-ray crystallographic analysis was started. Also fluorescence properties of the hemocyanin after dialysis against Tris-glycine buffer + 0.01 M EDTA pH 8.9 (so called “stripped” hemocyanin) and its fractions II and V were studied, as well as functional properties of the fractions by NMR. Finally the temperature-jump method was used for assaying the oxygen binding of the dissociating molecule and of preparations of isolated subunits. Nevertheless very little is known about the structure of the intact molecule. Schutter et al. suggested that the molecule possibly consists of two halves, combined in a staggered way, the halves themselves consisting of four subunits arranged in a square.

Purification, crystallization and X-ray crystallographic analysis of ATPase domain in transcription regulator DmpR

2019 ◽  
Vol 7 (2) ◽  
pp. 52-55
Author(s):  
Su-Jin Lee ◽  
In-Young Baek ◽  
Yan An ◽  
Woo-Chan Ahn ◽  
Kwang-Hyun Park ◽  
...  
Keyword(s):  
Crystallographic Analysis ◽  
Atpase Domain ◽  
X Ray ◽  
Transcription Regulator
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