1,721,088 research outputs found
The photochemical reaction of 1,4-naphthalenedicarbonitrile with aromatic pinacols and pinacol ethers
No full textPhotoinduced SET for the functionalization of alkanes
No full textThermochem. cycles show that deprotonation of alkane radical cations is an exothermic process, and indeed photoinduced SET between several alkanes and 1,2,4,5-tetracyanobenzene (TCB) is followed by efficient deprotonation of the radical cation with tertiary > secondary > primary selectivity; the alkyl radical is trapped by TCB- or, when present, by oxygen; when tetrachloro-p-benzoquinone is used in the place of TCB, the radical is further oxidized to the catio
Selective transformation of acetonides to orthoesters: an application of a photoinduced electron transfer process
No full text2 + 2 + 2 Cycloaddition vs Radical Ion Chemistry in the Photoreactions of 1,2,4,5-Benzenetetracarbonitrile with Alkenes in Acetonitrile
No full textPhotochemistry of 1-Cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(piperazin-1-yl)quinoline-3-carboxylic Acid (=Ciprofloxacin) in Aqueous Solutions
Full text linkThe 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(piperazin-1-yl)quinoline-3-carboxylic acid (=ciprofloxacin; 1) undergoes low-efficiency (Φ=0.07) substitution of the 6-fluoro by an OH group on irradiation in H2O via the ππ* triplet (detected by flash photolysis, λmax 610 nm, τ 1.5 μs). Decarboxylation is a minor process (≤5%). The addition of sodium sulfite or phosphate changes the course of the reaction under neutral conditions. Reductive defluorination is the main process in the first case, while defluorination is accompanied by degradation of the piperazine moiety in the presence of phosphate. In both cases, the initial step is electron-transfer quenching of the triplet (kq=2.3⋅108M−1 s−1 and 2.2⋅107M−1 s−1, respectively). Oxoquinoline derivative 1 is much more photostable under acidic conditions, and in this case the F-atom is conserved, and the piperazine group is stepwise degraded (Φ=0.001)
A photochemical generation of nitrosocarbonyl intermediates
No full textNitrosocarbonyl intermediates are photochemically generated from 1,2,4-oxadiazole-4-oxides and efficiently trapped with enes and dienes
Photochemistry of some trialkylsilyloxybenzylidenemalonic acid derivatives. C-Si bond fragmentation in a polarized excited state
No full text
- …
