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The reaction of enamine compounds with the Togni reagent in the presence of CuI afforded β-trifluoromethylated enamine intermediates, which were converted directly to biologically interesting trifluoromethylated 2H-azirines by an iodosobenzene (PhIO)-mediated intramolecular azirination in a one-pot process.

A new oxidative system of tert-butyl hydroperoxide (TBHP)/azodiisobutyronitrile (AIBN) has been used for the first time for a convenient, metal-free synthesis of substituted 2-aminothioazoles from active methylene ketone derivatives and thiourea. The reaction is postulated to proceed via an oxidative cyclization initiated by a radical process and followed by a condensation reaction.

A series of N-alkoxyindole-3-carbonitriles were synthesized, under mild conditions, via intramolecular heterocyclization of the readily available 3-alkoxyimino-2-arylalkylnitriles mediated by iodobenzene dichloride/zinc chloride. The mechanism of the reaction proposes the formation of a key intermediate of nitrenium cation from a chlorination and dechlorination process facilitated by the hypervalent iodine reagent and Lewis acid respectively.

Trace amine-associated receptor 1 (TAAR1) has been implicated in drug addiction, schizophrenia, depression and Parkinson’s disease (PD). To date, there are no reports on TAAR1-targeted probes for non-invasive quantification of receptor density in vivo. Herein, we report the synthesis of a 11C-labeled TAAR1 high-affinity antagonist N-(3-methoxyphenyl)-6-(pyrrolidin-1-yl)-5-(trifluoromethyl)nicotinamide [11C]4 (also named [11C]TAAR1-1911), as well as its physicochemical and preclinical evaluations for positron emission tomography (PET) imaging. This PET ligand was afforded using [11C]CH3I with the base NaOH in good radiochemical yield (non-decay corrected 14% relative to starting [11C]CO2), excellent radiochemical purities (>99%) and high molar activities (>37 GBq/µmol). Despite promising in vitro performance characteristics, [11C]4 did not exhibit in vivo specificity, potentially owing to fast metabolic degradation. Further studies are warranted to identify a suitable TAAR1 PET tracer, which would ultimately aid the development of TAAR1-directed therapeutic agents.

The reaction of enamine compounds with disulfides in the presence of tert-butyl hydroperoxide and a catalytic amount of tetrabutylammonium iodide conveniently afforded a variety of α-thioenamine compounds through the intermolecular oxidative C(sp2)S coupling. Incorporating both of the sulfide moieties in the disulfides into the final products under oxidative conditions, this novel approach exhibits the feature of atom efficiency. A radical mechanistic pathway for the reaction process has been proposed.

The α-amino-3-hydroxyl-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) belong to the family of ionotropic transmembrane receptors for glutamate (iGluRs) that are implicated in the pathology of neurological disorders and neurodegenerative diseases. Inspired by a recently developed positive allosteric modulator of AMPARs, 4-cyclopropyl-7-(3-methoxyphenoxy)-3,4-dihydro-2H-benzo[e][1,2,4]thiadiazine 1,1-dioxide (16; EC(50) = 2.0 nM), we designed a new synthetic route for N-protected phenolic precursor 13 and efficiently radiolabeled a PET ligand [(11)C]AMPA-1905 ([(11)C]16) using a modified one-pot two-step strategy in high radiochemical yield and high molar activity. Preliminary in vivo evaluation was carried out to investigate the suitability of [(11)C]16 as a potential PET probe for AMPAR imaging.