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 $10^{- 7} e / \sqrt{Hz}$ can be achieved which outperforms existing single charge electrometers.Comment: 13 pages, 7 figure

[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

Photochemical approach to the cyclohepta[b]indole scaffold by annulative two-carbon ring-expansion

We report on the implementation of the concept of a photochemically elicited two-carbon homologation of a π-donor–π-acceptor substituted chromophore by triple-bond insertion. Implementing a phenyl connector between the slide-in module and the chromophore enabled the synthesis of cylohepta[b]indole-type building blocks by a metal-free annulative one-pot two-carbon ring expansion of the five-membered chromophore. Post-irradiative structural elaboration provided founding members of the indolo[2,3-d]tropone family of compounds. Control experiments in combination with computational chemistry on this multibond reorganization process founded the basis for a mechanistic hypothesis

(2<i>R</i>,4<i>S</i>,5<i>S</i>)-5-Methoxy-4-methyl-3-oxohept-6-en-2-yl benzoate

The title compound, C16H20O4, was synthesized in the course of the total synthesis of fusaequisin A in order to verify and confirm the configurations of the stereogenic centers and to exclude the possibility of epimerization during the methylation process. The crystal structure of the title compound at 100 K has orthorhombic (P212121) symmetry. The absolute configuration was determined by anomalous dispersion and agrees with the configuration of the allylic alcohol used in the synthesis.</jats:p

Bis{decacarbonylbis[mu-2,2 `-(phenylimino)diethanolato]ditin(II)ditungsten(0)(2 Sn-W)} hexacarbonyltungsten(0)

In the title 2:1 adduct, [Sn(2)W(2)(C(10)H(13)NO(2))(2)(CO)(10)](2)[W(CO)(6)], the complete hexacarbonyltungsten molecule is generated by a crystallographic inversion centre. The heterometallic molecule features a central Sn(2)O(2) core with essentially equal Sn-O(ethoxy) bond lengths. The second ethoxy O and amine N atoms of each N,O,O'-tridentate ligand coordinate to one Sn atom only. The NO(3) donor atoms occupy basal positions and the W atom the apical position in a distorted square-pyramidal geometry for each Sn atom. The W atoms are approximately syn to each other but the central metal core is non-planar [W-Sn center dot center dot center dot Sn-W pseudo-torsion angle = 43.573 (16)degrees]. One of the carbonyl ligands in the heterometallic molecule is disordered over two orientations with equal occupancies. In the crystal, the heterometallic molecules associate via C-H center dot center dot center dot O interactions, forming supramolecular layers with undulating topology in the ab plane. These stack along the c axis, defining voids which are occupied by the W(CO)(6) molecules

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