scholarly journals New biphenyl iminium salt catalysts for highly enantioselective asymmetric epoxidation: role of additional substitution and dihedral angle

2016 ◽  
Vol 14 (18) ◽  
pp. 4220-4232 ◽  
Author(s):  
Philip C. Bulman Page ◽  
Christopher J. Bartlett ◽  
Yohan Chan ◽  
Steven M. Allin ◽  
Michael J. McKenzie ◽  
...  
Keyword(s):  
Dihedral Angle ◽  
Heterocyclic Ring ◽  
Asymmetric Epoxidation ◽  
Iminium Salt

The effects upon enantioselectivity of substitution in the heterocyclic ring of biaryl iminium salt catalysts for alkene epoxidation are reported. The influence of dihedral angle in these systems has been investigated. Enantioselectivities of up to 97% ee were observed.

scholarly journals Non-Aqueous Iminium Salt Mediated Catalytic Asymmetric Epoxidation.

ChemInform ◽  
2006 ◽  
Vol 37 (42) ◽  
Author(s):  
Philip C. Bulman Page ◽  
Benjamin R. Buckley ◽  
David Barros ◽  
A. John Blacker ◽  
Harry Heaney ◽  
...  
Keyword(s):  
Asymmetric Epoxidation ◽  
Iminium Salt ◽  
Catalytic Asymmetric

New Chiral Iminium Salt Catalysts for Asymmetric Epoxidation

2006 ◽  
Vol 2006 (3) ◽  
pp. 803-813 ◽  
Author(s):  
Philip C. Bulman Page ◽  
Benjamin R. Buckley ◽  
Gerasimos A. Rassias ◽  
A. John Blacker
Keyword(s):  
Asymmetric Epoxidation ◽  
Iminium Salt

scholarly journals Recent Advances in Iminium-Salt-Catalysed Asymmetric Epoxidation

2016 ◽  
Vol 2017 (6) ◽  
pp. 1034-1044 ◽  
Author(s):  
David P. Day ◽  
Philip B. Sellars
Keyword(s):  
Asymmetric Epoxidation ◽  
Iminium Salt ◽  
Recent Advances

scholarly journals Non-aqueous iminium salt mediated catalytic asymmetric epoxidation

Tetrahedron ◽  
2006 ◽  
Vol 62 (28) ◽  
pp. 6607-6613 ◽  
Author(s):  
Philip C. Bulman Page ◽  
Benjamin R. Buckley ◽  
David Barros ◽  
A. John Blacker ◽  
Harry Heaney ◽  
...  
Keyword(s):  
Asymmetric Epoxidation ◽  
Iminium Salt ◽  
Catalytic Asymmetric

scholarly journals Crystal structure of (4E)-4-(8-methoxy-2H-chromen-2-ylidene)-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one

2015 ◽  
Vol 71 (6) ◽  
pp. o414-o415
Author(s):  
Muhammad Salim ◽  
Munawar Ali Munawar ◽  
Muhammad Nawaz Tahir ◽  
Muhammad Shahid ◽  
Khizar Iqbal Malik
Keyword(s):  
Crystal Structure ◽  
Aromatic Ring ◽  
Dihedral Angle ◽  
Title Compound ◽  
Pyrazole Ring ◽  
Heterocyclic Ring ◽  
Phenyl Substituent ◽  
Π Interactions ◽  
Compound C ◽  
Centroid Distance

In the title compound, C20H16N2O3, the phenyl substituent attached to the pyrazole ring makes a dihedral angle of 4.87 (7)° with the rest of the molecule. In the crystal, molecules are connected into inversion dimers of theR22(14) type by pairs of C—H...O interactions. π–π interactions exist between the benzene and pyrazole rings at a distance of 3.701 (1) Å. Similarly, π–π interactions are present at a centroid–centroid distance of 3.601 (1) Å between the oxygen-containing heterocyclic ring and methoxy substituted aromatic ring of a neighbouring molecule. Additional C—H...π and C=O...π interactions are also observed.

ChemInform Abstract: A New System for Catalytic Asymmetric Epoxidation Using Iminium Salt Catalysts.

ChemInform ◽  
2010 ◽  
Vol 29 (36) ◽  
pp. no-no
Author(s):  
P. C. B. PAGE ◽  
G. A. RASSIAS ◽  
D. BETHELL ◽  
M. B. SCHILLING
Keyword(s):  
Asymmetric Epoxidation ◽  
Iminium Salt ◽  
Catalytic Asymmetric ◽  
New System

scholarly journals 5′-([1,1′-Biphenyl]-4-yl)-1′,1′′,3′′-trimethyldispiro[indane-2,2′-pyrrolidine-4′,5′′-[1,3]diazinane]-1,3,2′′,4′′,6′′-pentaone

2014 ◽  
Vol 70 (7) ◽  
pp. o759-o759 ◽  
Author(s):  
Subramanyahegde ◽  
Hosamani Amar ◽  
Yellappa Shivaraj ◽  
Giriyapura R. Vijayakumar ◽  
Bandrehalli Siddagangaiah Palakshamurthy
Keyword(s):  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Title Compound ◽  
Heterocyclic Ring ◽  
Ring System ◽  
Dihedral Angles ◽  
Central Ring ◽  
Envelope Conformation ◽  
Compound C ◽  
Benzene Rings

In the title compound, C30H25N3O5, the central five-membered heterocyclic ring adopts an envelope conformation, with the N atom as the flap. The dihedral angles between this central ring and the pendant indane ring system, the trione and benzene rings are 87.49 (5), 82.95 (10) and 72.42 (10)°, respectively. The dihedral angle between the rings of the biphenyl group is 45.99 (13)°. In the crystal, molecules are linked by C—H...O hydrogen bonds into [101]C(12) chains.

scholarly journals The ability to overcome multidrug resistance of tumor cell lines by novel acridine cytostatics with condensed heterocyclic rings.

2002 ◽  
Vol 49 (1) ◽  
pp. 87-92 ◽  
Author(s):  
Maria M Bontemps-Gracz ◽  
Agnieszka Kupiec ◽  
Ippolito Antonini ◽  
Edward Borowski
Keyword(s):  
Multidrug Resistance ◽  
Tumor Cell ◽  
Cytotoxic Activity ◽  
Cell Lines ◽  
Human Tumor ◽  
Heterocyclic Ring ◽  
Tumor Cell Lines ◽  
Human Tumor Cell Lines

Two recently synthesized groups of acridine cytostatics containing fused heterocyclic ring(s): pyrazoloacridines (PAC) and pyrazolopyrimidoacridines (PPAC) were tested in regard to their in vitro cytotoxic activity towards a panel of sensitive and resistant human tumor cell lines. The obtained results corroborate our earlier hypothesis on the essential role of heterocyclic ring fused to the acridine moiety in the ability of acridine cytostatics to overcome multidrug resistance of tumor cells. The presence, location and kind of substituents considerably influenced both the cytotoxic activity of the derivatives and their ability to overcome multidrug resistance. The same factors also affected the cytostatics ability to differentiate between tumor cell lines with various types of drug exporting pumps.

Sharpless Asymmetric Epoxidation: Applications in the Synthesis of Bioactive Natural Products

2020 ◽  
Vol 17 ◽  
Author(s):  
Suélen Karine Sartori ◽  
Izabel Luzia Miranda ◽  
Marisa Alves Nogueira Diaz ◽  
Gaspar Diaz-Muñoz
Keyword(s):  
Natural Products ◽  
Building Blocks ◽  
Heterocyclic Ring ◽  
Biologically Active ◽  
Asymmetric Epoxidation ◽  
Allylic Alcohols ◽  
Titanium Tetraisopropoxide ◽  
Bioactive Natural Products ◽  
Tert Butyl Hydroperoxide ◽  
Sharpless Asymmetric Epoxidation

: This review discusses an important synthetic tool proposed by K. B. Sharpless in 1980, known as the Sharpless asymmetric epoxidation of allylic alcohols, and examines its use in the total synthesis of representative exponents of biologically active natural products. Focus is given to the synthesis of simple to highly complex secondary metabolites, including lactones, amino acids, diterpenes, and macrolides. The Sharpless approach involves the use of a catalyst, titanium tetraisopropoxide [Ti(OiPr)4], dialkyl tartrate as chiral ligand, and tert-butyl hydroperoxide (TBHP) as oxidizing agent. The method allows converting allylic alcohols to epoxides, which are chiral building blocks and versatile intermediates in the synthesis of natural products. The biological and synthetic importance of epoxides lies in the susceptibility of the threemembered heterocyclic ring to stereo- and regioselective opening by nucleophilic or acidic reagents, providing oxygen adducts.

ChemInform Abstract: Carbohydrate-Derived Iminium Salt Organocatalysts for the Asymmetric Epoxidation of Alkenes.

ChemInform ◽  
2015 ◽  
Vol 46 (10) ◽  
pp. no-no
Author(s):  
Philip C. Bulman Page ◽  
Yohan Chan ◽  
John Liddle ◽  
Mark R. J. Elsegood
Keyword(s):  
Asymmetric Epoxidation ◽  
Iminium Salt ◽  
Epoxidation Of Alkenes
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