14 research outputs found
[4-(Di-tert-butylfluorosilanyl)phenyl]methanol
The asymmetric unit of the title compound, C15H25FOSi, contains two independent molecules. Each of the Si atoms approximates the expected tetrahedral geometry with Si—F bond lengths of 1.6128 (11) and 1.6068 (11) Å in the two independent molecules. In the crystal, supramolecular chains along a are found mediated by O—H⋯O hydrogen bonds
τBu₂SiF-Derivatized D₂-Receptor Ligands: The First SiFA-Containing Small Molecule Radiotracers for Target-Specific PET-Imaging
The synthesis, radiolabeling and in vitro evaluation of new silicon-fluoride acceptor (SiFA) derivatized D-2-receptor ligands is reported. The SiFA-technology simplifies the introduction of fluorine-18 into target specific biomolecules for Positron-Emission-Tomography (PET). However, one of the remaining challenges, especially for small molecules such as receptor-ligands, is the bulkiness of the SiFA-moiety. We therefore synthesized four Fallypride SiFA-conjugates derivatized either directly at the benzoic acid ring system (SiFA-DMFP, SiFA-FP, SiFA-DDMFP) or at the butyl-side chain (SiFA-M-FP) and tested their receptor affinities. We found D2-receptor affinities for all compounds in the nanomolar range (Ki(SiFA-DMFP) = 13.6 nM, Ki(SiFA-FP) = 33.0 nM, Ki(SiFA-DDMFP) = 62.7 nM and Ki(SiFA-M-FP) = 4.21 nM). The radiofluorination showed highest yields when 10 nmol of the precursors were reacted with F-18]fluoride/TBAHCO(3) in acetonitrile. After a reversed phased cartridge purification the desired products could be isolated as an injectable solution after only 10 min synthesis time with radiochemical yields (RCY) of more than 40% in the case of SiFA-DMFP resulting in specific activities >41 GBq/mu mol (>1,100 Ci/mmol). Furthermore, the radiolabeled products were shown to be stable in the injectable solutions, as well as in human plasma, for at least 90 min
Design of a Cooper pair box electrometer for application to solid-state and astroparticle physics
We describe the design and principle of operation of a fast and sensitive
electrometer operated at millikelvin temperatures, which aims at replacing
conventional semiconducting charge amplifiers in experiments needing low
back-action or high sensitivity. The electrometer consists of a Cooper Pair box
(CPB) coupled to a microwave resonator, which converts charge variations to
resonance frequency shifts. We analyze the dependence of the sensitivity on the
various parameters of the device, and derive their optimization. By exploiting
the nonlinearities of this electrometer, and using conventional nanofabrication
and measurement techniques, a charge sensitivity of a few can be achieved which outperforms existing single charge
electrometers.Comment: 13 pages, 7 figure
Progress toward the Total Synthesis of Gukulenin A: Photochemically Triggered Two-Carbon Ring Expansion Key to α‑Tropolonic Ether Synthesis
The
ex-chiral-pool synthesis of an advanced gukulenin A precursor
from (−)-piperitone is revealed. Key C/C connecting maneuvers
to the synthesis of a C<sub>2</sub> dissymmetric bis(α-tropolonic)
ether building block are a ring-contracting Meinwald rearrangement,
a photochemically triggered two-carbon ring expansion, and a homodimerization
by cross-metathesis
Development of an Alkyne Analogue of the de Mayo Reaction: Synthesis of Medium‐Sized Carbacycles and Cyclohepta[ b
Embedded medium-sized carbacycles and cyclohepta [b] indoles occur frequently as scaffold elements in natural products and bioactive compounds. Described herein is a conceptionally novel photochemically triggered cascade process to these scaffolds. Key to the cascading ring-expansion process is an unprecedented intramolecular alkyne analogue of the de Mayo reaction
Development of an Alkyne Analogue of the de Mayo Reaction: Synthesis of Medium‐Sized Carbacycles and Cyclohepta[ b ]indoles
Embedded medium-sized carbacycles and cyclohepta [b] indoles occur frequently as scaffold elements in natural products and bioactive compounds. Described herein is a conceptionally novel photochemically triggered cascade process to these scaffolds. Key to the cascading ring-expansion process is an unprecedented intramolecular alkyne analogue of the de Mayo reaction
Progress toward the Total Synthesis of Gukulenin A: Photochemically Triggered Two-Carbon Ring Expansion Key to α‑Tropolonic Ether Synthesis
The
ex-chiral-pool synthesis of an advanced gukulenin A precursor
from (−)-piperitone is revealed. Key C/C connecting maneuvers
to the synthesis of a C<sub>2</sub> dissymmetric bis(α-tropolonic)
ether building block are a ring-contracting Meinwald rearrangement,
a photochemically triggered two-carbon ring expansion, and a homodimerization
by cross-metathesis