Preclinical evaluation of a brain penetrant PARP PET imaging probe in rat glioblastoma and nonhuman primates.

Purpose: Currently, there are multiple active clinical trials involving poly(ADP-ribose) polymerase (PARP) inhibitors in the treatment of glioblastoma. The noninvasive quantification of baseline PARP expression using positron emission tomography (PET) may provide prognostic information and lead to more precise treatment. Due to the lack of brain-penetrant PARP imaging agents, the reliable and accurate in vivo quantification of PARP in the brain remains elusive.

Pd-Boron-Catalyzed One Carbon Isomerization of Olefins: Water Assisted Process at Room Temperature.

A palladium-boronate/borane-system -catalyzed isomerization of olefins has been uncovered. An efficient catalytic combination of [Pd(OAc)]-boronate-PCy-enabled olefin isomerization at 80 °C has been investigated. Addition of water to the reaction showed a remarkable improvement and the isomerization occurred at ambient temperature.

Generation of Hydrogen from Water: A Pd-Catalyzed Reduction of Water Using Diboron Reagent at Ambient Conditions.

Production of hydrogen from renewable sources, particularly from water, is an intensive area of research, which has far-reaching relevance in hydrogen economy. A homogeneous catalytic method is presented for producing clean hydrogen gas from water, in a reaction of water with a diboron compound as the reductant, under ambient reaction conditions. The Pd-catalytic system is stable in water and displays excellent recyclability.

Pd-Catalyzed Hydroborylation of Alkynes: A Ligand Controlled Regioselectivity Switch for the Synthesis of α- or β-Vinylboronates.

A ligand controlled selective hydroborylation of alkynes to α- or β-vinylboronates has been developed using a Pd catalyst. The high α-selectivity displayed by this reaction can be switched to furnish β-vinylboronates by altering the ligand from a trialkylphosphine to N-heterocyclic carbene. A variety of terminal alkynes are shown to furnish the corresponding α- or β-vinylboronates in good to excellent selectivity and yield.

Regioselective synthesis of vinyl halides, vinyl sulfones, and alkynes: a tandem intermolecular nucleophilic and electrophilic vinylation of tosylhydrazones.

A diazo species is trapped in an intermolecular fashion by two independent ion species in tandem at the carbene center to install an electrophile and a nucleophile on the same carbon. This metal-free concept, which is unprecedented, has been illustrated by regioselective synthesis of a variety of vinyl halides, vinyl sulfones, and alkyne derivatives.

Pd-catalyzed cross-coupling reactions of hydrazones: regioselective synthesis of highly branched dienes.

The regioselective formation of highly branched dienes is a challenging task. Design and exploration of alternative working models to achieve such a regioselectivity to accomplish highly branched dienes is considered to be a historical advancement of Heck reaction to construct branched dienes. On the basis of the utility of carbene transfer reactions, in the reaction of hydrazones with Pd(II) under oxidative conditions, we envisioned obtaining a Pd-bis-carbene complex with α-hydrogens, which can lead to branched dienes.

Palladium catalyzed coupling of tosylhydrazones with aryl and heteroaryl halides in the absence of external ligands: synthesis of substituted olefins.

Palladium catalyzed cross-coupling reaction of hydrazones with aryl halides in the absence of external ligand is reported. The versatility of this coupling reaction is demonstrated in showcasing the selectivity of coupling reaction in the presence of hydroxyl and amine functional groups. This method allows synthesizing a variety of heterocyclic compounds, which are difficult to access from other traditional methods and are not synthesized by employing similar coupling reactions.