1362019-94-0Relevant academic research and scientific papers
Crown Ether Nucleophilic Catalysts (CENCs): Agents for Enhanced Silicon Radiofluorination
Jana, Susovan,Al-Huniti, Mohammed H.,Yang, Bo Yeun,Lu, Shuiyu,Pike, Victor W.,Lepore, Salvatore D.
, p. 2329 - 2335 (2017)
New bifunctional phase transfer agents were synthesized and investigated for their abilities to promote rapid fluorination at silicon. These agents, dubbed crown ether nucleophilic catalysts (CENCs), are 18-crown-6 derivatives containing a side-arm and a potentially nucleophilic hydroxyl group. These CENCs proved efficacious in the fluorination of hindered silicon substrates, with fluorination yields dependent on the length of linker connecting the metal chelating unit to the hydroxyl group. The efficacy of these CENCs was also demonstrated for rapid radiofluorination under mild conditions for eventual application in molecular imaging with positron emission tomography (PET). The hydrolysis-resistant aryl silicon fragment is promising as a convenient synthon for labeling potential PET radiotracers.
Designing Silylated l-Amino Acids using a Wittig Strategy: Synthesis of Peptide Derivatives and 18F-Labelling
Rugeri, Baptiste,Audi, Hassib,Jewula, Pawel,Koudih, Radouane,Malacea-Kabbara, Raluca,Vimont, Delphine,Schulz, Jürgen,Fernandez, Philippe,Jugé, Sylvain
, p. 5399 - 5409 (2017)
An efficient semisynthesis of silylated l-amino acids by reaction of silylated benzaldehydes with a phosphonium l-amino acid used as a Wittig reagent is described. The efficiency of the silylated l-amino acids in peptide synthesis was investigated by coup
Folding of alternating dialkylsilylene-spaced donor-acceptor copolymers: The oligomer approach
Chen, Chih-Hsien,Chen, Wen-Hao,Liu, Yi-Hung,Lim, Tsong-Shin,Luh, Tien-Yau
, p. 347 - 354 (2012/03/09)
A series of oligmers with donor-acceptor pairs separated by diisopropylsilylene (iPr2Si) spacers, composed of monomer 4b, dimer 5, trimer 6, and tetramer 7, were synthesized to scrutinize the folding behavior. Monomer 4a with a dimethylsilylene (Me2Si) spacer was also prepared for comparison. The 4-aminostyrene moiety was used as the donor and the stilbene moiety as the acceptor. Both steady-state and time-resolved fluorescence spectroscopic measurement were made. Regardless of the substituents on the silicon atom, the emission spectra of 4a and 4b exhibit both local excited (LE) emission of the acceptor chromophore and emission from the charge-separated state (CT emission), which are similar to that of the corresponding Me2Si-spaced copolymer 2a with the same donor and acceptor chromophores, but different from that of the copolymer with the iPr2Si spacer 2b. Dimer 5 behaves like 4 and 2a. As the chain length of the oligomers increases, the emission properties of the higher homologues become prone to that of 2b. Thus, tetramer 7 exhibits emission from the charge-transfer complex, which is essentially same as that of 2b. Moreover, charge-transfer absorptions emerge in 6 and 7. These results suggest that the folding nature of oligomers approaches that of the corresponding polymer, as the degree of oligomerization increases, and the electronic interactions between adjacent donor-acceptor pairs are controlled by the steric effect of the substituents on the silicon atoms and concomitant amplification of the stabilizing energy by extending the distance of the folding structure. Copyright
