We present the synthesis and characterization of a highly efficient thorium chelator, derived from the octadentate hydroxypyridinone class of compounds. The chelator forms extremely stable complexes with fast formation rates in the presence of Th-227 (ambient temperature, 20min). In addition, mouse biodistribution data are provided which indicate rapid hepatobiliary excretion route of the chelator which, together with low bone uptake, supports the stability of the complex in vivo. The carboxylic acid group may be readily activated for conjugation through the ɛ-amino groups of lysine residues in biomolecules such as antibodies. This chelator is a critical component of a new class of Targeted Thorium Conjugates (TTCs) currently under development in the field of oncology.
A toxic plant, Veratrum album (ssp. viriscens), was found to have an inhibitory effect on Hedgehog (Hh), a developmental signaling pathway that has been shown to be active during development, in adult stem cells and in numerous human tumors. Based on earlier studies it was believed that the known Hh inhibitor cyclopamine was present in V. album (ssp. viriscens). Here we show that instead of cyclopamine, dihydroveratramine (DHV) was found in V. album (ssp. viriscens). These compounds are easily mistaken for each other, as both substances share the same molecular weight, and the same main MS/MS fragments. DHV was found to be a less potent Hh inhibitor compared to cyclopamine. This is the first reported occurrence of DVH in nature.
Decarboxylation of allylic esters of 4-carboxypyrimidines in toluene at 111 °C in the presence of a Pd(0) catalyst, gives a mixture of a 4-alkenylpyrimidine and a pyrimidine unsubstituted in the 4-position. If the decarboxylation is carried out in the presence of benzaldehyde, then benzaldehyde is added to the 4-position. Decarboxylation of 4-carboxypyrimidines in the presence of different electrophiles, results in incorporation of the electrophile into the 4-position together with a pyrimidine unsubstituted in the 4-position. Use of microwave irradiation enhances the rate of the decarboxylations.
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