62 research outputs found
Direct C(sp2)-H chlorination of ketene dithioacetals using FeCl3 as the chloride source and PhI(OAc)2 as an oxidant
The Non-Anhydrous, Minimally Basic Synthesis of the Dopamine D2 Agonist [18F]MCL-524
The dopamine D2 agonist MCL-524 is selective for the D2 receptor in the high-affinity state (D2high), and, therefore, the PET analogue, [18F]MCL-524, may facilitate the elucidation of the role of D2high in disorders such as schizophrenia. However, the previously reported synthesis of [18F]MCL-524 proved difficult to replicate and was lacking experimental details. We therefore developed a new synthesis of [18F]MCL-524 using a ânon-anhydrous, minimally basicâ (NAMB) approach. In this method, [18F]Fâ is eluted from a small (10â12 mg) trap-and-release column with tetraethylammonium tosylate (2.37 mg) in 7:3 MeCN:H2O (0.1 mL), rather than the basic carbonate or bicarbonate solution that is most often used for [18F]Fâ recovery. The tosylated precursor (1 mg) in 0.9 mL anhydrous acetonitrile was added directly to the eluate, without azeotropic drying, and the solution was heated (150 °C/15 min). The catechol was then deprotected with the Lewis acid In(OTf)3 (10 equiv.; 150 °C/20 min). In contrast to deprotection with protic acids, Lewis-acid-based deprotection facilitated the efficient removal of byproducts by HPLC and eliminated the need for SPE extraction prior to HPLC purification. Using the NAMB approach, [18F]MCL-524 was obtained in 5â9% RCY (decay-corrected, n = 3), confirming the utility of this improved method for the multistep synthesis of [18F]MCL-524 and suggesting that it may applicable to the synthesis of other 18F-labeled radiotracers
Electronic Effects in the Pt-Catalyzed Cycloisomerization of Propargylic Esters: Synthesis of 2,3-Disubstituted Indolizines as a Mechanistic Probe
Gold-Catalyzed Homogeneous Oxidative CâO Bond Formation: Efficient Synthesis of 1-Benzoxyvinyl Ketones
Gold-Catalyzed Electrophilic Addition to Arylalkynes. A Facile Method for the Regioselective Synthesis of Substituted Naphthalenes
Synthesis of Stable Gold(III) Pincer Complexes with Anionic Heteroatom Donors
A series of goldÂ(III) complexes supported
by pyridine-based bisÂ(amidate),
bisÂ(carboxylate), and bisÂ(iminothiolate) substituents is reported.
These compounds represent rare examples of pincer-ligated goldÂ(III)
centers with multiple anionic heteroaom donors. Reactivity and electrochemical
studies demonstrate the stability of these compounds and the marked
difference in reduction potentials with varying ligand scaffolds
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