Mendes, Joseane A Merino, Pedro Soler, Tatiana Salustiano, Eduardo J Costa, Paulo R R Yus, Miguel Foubelo, Francisco Buarque, Camilla D
Published in
The Journal of organic chemistry
The addition of 2-bromobenzylmagnesium bromide to chiral N- tert-butanesulfinyl imines derived from tetralone-type ketones proceeds with high levels of diastereocontrol. The resulting sulfinamide derivatives were transformed into dibenzoazaspiro compounds after a palladium-catalyzed intramolecular N-arylation. DFT calculations have been performed t...
Bartetzko, Max P Schuhmacher, Frank Seeberger, Peter H Pfrengle, Fabian
Published in
The Journal of organic chemistry
Pectin is a structurally complex plant polysaccharide with many industrial applications in food products. The structural elucidation of pectin is aided by digestion assays with glycosyl hydrolases. We report the automated glycan assembly of oligosaccharides related to the arabinogalactan side chains of pectin as novel biochemical tools to determine...
Heung Sik Hahm Chien-Fu Liang Chian-Hui Lai Richard J. Fair Frank Schuhmacher Peter H. Seeberger
Published in
The Journal of Organic Chemistry
Rönsberg, David Debbab, Abdessamad Mándi, Attila Vasylyeva, Vera Böhler, Philip Stork, Björn Engelke, Laura Hamacher, Alexandra Sawadogo, Richard Marc Diederich
...
Published in
The Journal of Organic Chemistry
Four tetrahydroxanthone dimers (1-4) and four biogenetically related monomers (5-8), including the new derivatives (4-6), were isolated from the endophyte Phomopsis longicolla. The absolute configurations of 2-4 were established for the first time by TDDFT ECD calculations and that of phomoxanthone A (1) was revised by X-ray crystallography. Phomox...
Kirby, Anthony J Medeiros, Michelle Mora, José R Oliveira, Pedro S M Amer, Almahdi Williams, Nicholas H Nome, Faruk
Published in
The Journal of Organic Chemistry
Notwithstanding its half-life of 70 years at 25 °C, the spontaneous hydrolysis of the anion of di-2-pyridyl phosphate (DPP) is thousands of times faster (ca. 3000 at 100 °C, over 10000-fold at 25 °C) than expected for a diester with leaving groups of pK(a) 9.09. The kinetic parameters do not permit a conclusive choice between five possible mechanis...
Angelini, Guido De Maria, Paolo Chiappe, Cinzia Fontana, Antonella Gasbarri, Carla Siani, Gabriella
Published in
The Journal of Organic Chemistry
While the solvent effect on the rate of tautomerization of 2-nitrocyclohexanone in several organic solvents appears to depend essentially on the permittivity of the solvent, a different behavior is observed in some ionic liquids. In particular the rate of the reaction in ionic liquids (ILs) is much faster than expected solely on the basis of the pe...
Ghosh, Arun K Shurrush, Khriesto Kulkarni, Sarang
Published in
The Journal of Organic Chemistry
An asymmetric synthesis of anti-aldol segments via a nonaldol route is described. The strategy involves a highly diastereoselective synthesis of functionalized tetrahydrofuran derivatives from optically active 4-phenylbutyrolactone. Treatment of the tetrahydrofuran derivatives with a Lewis acid and acetic anhydride provided the corresponding ring-o...
Ghidu, Victor P Wang, Jingqi Wu, Bin Liu, Qingsong Jacobs, Aaron Marnett, Lawrence J Sulikowski, Gary A
Published in
The Journal of organic chemistry
Apoptolidins A-D are microbial secondary metabolites shown to be selectively cytotoxic against several cancer cell lines and noncytotoxic against normal cells. Total syntheses of apoptolidinones A and D are reported. The efficient synthetic strategy leading to the apoptolidinones features construction of the common 20-membered macrolactone by an in...
Braten, Miles N Castro, Claire Herges, Rainer Köhler, Felix Karney, William L
Published in
The Journal of Organic Chemistry
A new global minimum for [12]annulene has been computationally located. This mono-trans minimum 5 (CCCCCT) is computed to be 1.5 kcal/mol more stable (CCSD(T)/cc-pVDZ//BHHLYP/6-311+G**) than the known tri-trans isomer 1 (CTCTCT) and 2.4 kcal/mol lower than the di-trans isomer 4 (CCTCCT), for which there is indirect evidence. The barriers for severa...
Roussel, Christian Vanthuyne, Nicolas Bouchekara, Mohamed Djafri, Ayada Elguero, José Alkorta, Ibon
Published in
The Journal of Organic Chemistry
A series of original atropisomeric iminothiazolines 1 in which X = OH or (and) Y = OH were prepared from the corresponding methoxy precursors. The resolution of the atropisomeric enantiomers on chiral support is reported, and the barriers to enantiomerization are given. These barriers were determined either by off-line racemization studies or by tr...
