23731-38-6Relevant academic research and scientific papers
Fries rearrangement of aryl formates: A mechanistic study by means of 1H, 2H, and 11B NMR spectroscopy and DFT calculations
Bagno, Alessandro,Kantlehner, Willi,Kress, Ralf,Saielli, Giacomo,Stoyanov, Edmont
, p. 9331 - 9340 (2006)
(Figure Presented) 1H, 2H, and 11B NMR spectroscopy has been used to study the mechanism of the Fries rearrangement of aryl formates promoted by boron trichloride by monitoring both the substrate and the Lewis acid. DFT calculations were employed to investigate the energetics of several reaction paths and to calculate NMR chemical shifts of key intermediates and products. After the formation of a 1:1 substrate - Lewis acid adduct, the rearrangement proceeds in two steps, beginning with the cleavage of the ester bond and the release of formyl chloride in situ, which, in turn, acts as a formylating agent, introducing an aldehydic functionality into the aromatic ring. The high regioselectivity (only the ortho product is obtained) is also accounted for by the proposed intermolecular, Lewis acid-assisted mechanism.
Sequential photo-oxidation of methanol to methyl formate on TiO 2(110)
Phillips, Katherine R.,Jensen, Stephen C.,Baron, Martin,Li, Shao-Chun,Friend, Cynthia M.
supporting information, p. 574 - 577 (2013/03/14)
Methyl formate is produced from the photo-oxidation of methanol on preoxidized TiO2(110). We demonstrate that two consecutive photo-oxidation steps lead to methyl formate using mass spectrometry and scanning tunneling microscopy. The first step in methanol oxidation is formation of methoxy by the thermal dissociation of the O-H bond to yield adsorbed CH3O and water. Formaldehyde is produced via hole-mediated oxidation of adsorbed methoxy in the first photochemical step. Next, transient HCO is made photochemically from formaldehyde. The HCO couples with residual methoxy on the surface to yield methyl formate. Exposure of the titania surface to O 2 is required for these photo-oxidation steps in order to heal surface and near-surface defects that can serve as hole traps. Notably, residual O adatoms are not required for photochemical production of methyl formate or formaldehyde. All O adatoms react thermally with methanol to form methoxy and gaseous water at rt, leaving a surface devoid of O adatoms. The mechanism provides insight into the photochemistry of TiO2 and suggests general synthetic pathways that are the result of the ability to activate both alkoxides and aldehydes using photons.
Steric Course of Ketopantoate Hydroxymethyltransferase in E. coli
Aberhart, D. John,Russell, David J.
, p. 4902 - 4906 (2007/10/02)
The conversion of α-ketoisovaleric acid (α-KIVA) to ketopantoate by the 5,10-methylenetetrahydrofolate-dependent enzyme ketopantoate hydroxymethyltransferase (KHMT) in E. coli has been shown to proceed in a retention mode at the β-position of α-KIVA. 5,10-methylenetetrahydrofolate formed in vivo by serine hydroxymethyltransferase (SHMT) from stereospecifically deuterated (3S-d1) serine was converted by KHMT into an ca. 3:1 ratio of deuterated ketopantoates with the 4S isomer predominating.The results indicate that KHMT and SHMT have the same overall steric course in E. coli.
