New Macrocyclic Ligands. V. Synthetic, Crystallographic and Computational Studies of a New N2O6-Heteroatom Cage

1994 ◽  
Vol 47 (6) ◽  
pp. 1155 ◽  
Author(s):  
IM Atkinson ◽  
LF Lindoy ◽  
OA Matthews ◽  
GV Meehan ◽  
AN Sobolev ◽  
...  
Keyword(s):  
Macrocyclic Ligands ◽  
Computational Studies ◽  
Mo Calculations ◽  
X Ray ◽  
Semiempirical Mo Calculations ◽  
Cage Molecule

The synthesis, characterization and X-ray structure of a new cage molecule containing six phenoxy and two nitrogen heteroatoms is reported. Semiempirical MO calculations have been used to probe the topological rigidity of the cage relative to related aliphatic systems.

New Macrocyclic Ligands. XI. Synthesis, X-Ray Structure and Computational Studies of a New N2O4S2-Heteroatom Cage

2000 ◽  
Vol 53 (9) ◽  
pp. 799 ◽  
Author(s):  
Ian M. Atkinson ◽  
David C. R. Hockless ◽  
Leonard F. Lindoy ◽  
Owen A. Matthews ◽  
George V. Meehan ◽  
...  
Keyword(s):  
Single Crystals ◽  
Structure Determination ◽  
Macrocyclic Ligands ◽  
Computational Studies ◽  
Mo Calculations ◽  
X Ray ◽  
Semiempirical Mo Calculations ◽  
Cage Molecule ◽  
Helical Configuration

The synthesis and single-crystal X-ray structure determination of a new cage molecule containing four oxygen, two sulfur, and two nitrogen heteroatoms are described. The structure determination shows that a twist occurs about each (tribenzyl) nitrogen bridgehead so that an overall helical configuration within putative quasi-2 symmetry is generated; both nitrogens have their lone pairs orientatedexo. Single crystals of this compound are homochiral. Semiempirical MO calculations have been used to probe the topological rigidity of this system relative to the more symmetrical analogue incorporating six oxygen and two nitrogen heteroatoms reported previously. The introduction of the sulfur atoms appears to restrict the facile interconversion between enantiomers that was predicted for the N2O6-analogue mentioned above. The implications of the structure for the design of larger cages are discussed.

Molecular Structure of Heterocycles: 4# NMR Spectroscopy, X-Ray Diffraction, and Semiempirical Mo Calculations of 3-Phenyl-5-Hydroxy- 5-Trichloromethyl-4,5-Dihydro-FH-Pyrazole-1-Carboxyamide

1999 ◽  
Vol 32 (5) ◽  
pp. 851-865 ◽  
Author(s):  
Helio Bonacorso ◽  
Marcos Martins ◽  
Nilo Zanatta ◽  
Marli Oliveira ◽  
Alexandre Wentz ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Nmr Spectroscopy ◽  
X Ray Diffraction ◽  
Mo Calculations ◽  
X Ray ◽  
Semiempirical Mo Calculations

N-[(2-Naphthyloxy)methyl] benzazoles: Synthesis and Investigation by X-ray Analysis and by Semiempirical MO Calculations

1990 ◽  
Vol 123 (5) ◽  
pp. 1185-1191 ◽  
Author(s):  
Alan R. Katritzky ◽  
Gus J. Palenik ◽  
Jean-Jacques Vanden Eynde ◽  
Zeying Zhang ◽  
Ernst Anders ◽  
...  
Keyword(s):  
Mo Calculations ◽  
X Ray ◽  
Semiempirical Mo Calculations

Molecular Structure of Heterocycles: 2#NMR Spectroscopy, X- ray Diffraction, and Semiempirical MO Calculations of 5-Bromo-4, 6-dimethoxy-4-trichloromethyl-hexahydropyrimidin-2-one.

1998 ◽  
Vol 31 (6) ◽  
pp. 1125-1139 ◽  
Author(s):  
Marcos A. P. Martins ◽  
Nilo Zanatta ◽  
Iraci L. Pacholski ◽  
Hélio G. Bonacorso ◽  
Manfredo Hömer ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Nmr Spectroscopy ◽  
X Ray Diffraction ◽  
Mo Calculations ◽  
X Ray ◽  
Semiempirical Mo Calculations

ChemInform Abstract: New Macrocyclic Ligands. Part 11. Synthesis, X-Ray Structure and Computational Studies of a New N2O4S2-Heteroatom Cage.

ChemInform ◽  
2001 ◽  
Vol 32 (17) ◽  
pp. no-no
Author(s):  
Ian M. Atkinson ◽  
David C. R. Hockless ◽  
Lindoy Leonard F. Lindoy Leonard F. ◽  
Owen A. Matthews ◽  
George V. Meehan ◽  
...  
Keyword(s):  
Macrocyclic Ligands ◽  
Computational Studies ◽  
X Ray

ChemInform Abstract: N-((2-Naphthyloxy)methyl)benzazoles: Synthesis and Investigation by X-Ray Analysis and by Semiempirical MO Calculations

ChemInform ◽  
1990 ◽  
Vol 21 (32) ◽  
Author(s):  
A. R. KATRITZKY ◽  
G. J. PALENIK ◽  
E. ANDERS ◽  
J. G. TROPSCH ◽  
J.-J. VANDEN EYNDE ◽  
...  
Keyword(s):  
Mo Calculations ◽  
X Ray ◽  
Semiempirical Mo Calculations

Molecular Structure of Heterocycles: NMR Spectroscopy, Semiempirical MO Calculations and X-Ray Diffraction of 3,3a,4,5,6,7-Hexahydro-3-trichloromethyl[2,1]benzoisoxazole

1997 ◽  
Vol 30 (4) ◽  
pp. 661-675 ◽  
Author(s):  
Marcos A. P. Martins ◽  
Alex F. C. Flores ◽  
Rogério A. Freitag ◽  
Nilo Zanatta ◽  
Manfredo Hörner ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Nmr Spectroscopy ◽  
X Ray Diffraction ◽  
Mo Calculations ◽  
X Ray ◽  
Semiempirical Mo Calculations

scholarly journals Structural basis of the stereoselective formation of the spirooxindole ring in the biosynthesis of citrinadins

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhiwen Liu ◽  
Fanglong Zhao ◽  
Boyang Zhao ◽  
Jie Yang ◽  
Joseph Ferrara ◽  
...  
Keyword(s):  
High Resolution ◽  
Organic Synthesis ◽  
Indole Alkaloids ◽  
Site Directed Mutagenesis ◽  
Structural Basis ◽  
Directed Mutagenesis ◽  
Computational Studies ◽  
X Ray ◽  
Evolutionary Branch ◽  
Catalytic Mechanisms

AbstractPrenylated indole alkaloids featuring spirooxindole rings possess a 3R or 3S carbon stereocenter, which determines the bioactivities of these compounds. Despite the stereoselective advantages of spirooxindole biosynthesis compared with those of organic synthesis, the biocatalytic mechanism for controlling the 3R or 3S-spirooxindole formation has been elusive. Here, we report an oxygenase/semipinacolase CtdE that specifies the 3S-spirooxindole construction in the biosynthesis of 21R-citrinadin A. High-resolution X-ray crystal structures of CtdE with the substrate and cofactor, together with site-directed mutagenesis and computational studies, illustrate the catalytic mechanisms for the possible β-face epoxidation followed by a regioselective collapse of the epoxide intermediate, which triggers semipinacol rearrangement to form the 3S-spirooxindole. Comparing CtdE with PhqK, which catalyzes the formation of the 3R-spirooxindole, we reveal an evolutionary branch of CtdE in specific 3S spirocyclization. Our study provides deeper insights into the stereoselective catalytic machinery, which is important for the biocatalysis design to synthesize spirooxindole pharmaceuticals.

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