Synthesis and biological evaluation of radioiodinated N-2-(4-piperidyl)ethyl benzamides

Design, synthesis, and biological activity of human glutaminyl cyclase inhibitors against Alzheimer's disease

Human glutaminyl cyclase (hQC) has emerged as a critical target in Alzheimer's disease (AD) due to its role in generating pyroglutamate-modified amyloid β (pE-Aβ). In this study, 13 compounds were designed as target compounds by fragment-based drug design (FBDD) and molecular docking, and subsequently assessed for drug-like properties and predicted inhibitory activities through ADMET analysis and Uni-QSAR modeling. Target compounds were synthesized via systematic multi-step approaches, with acceptable yields. The in vitro hQC enzyme inhibition assay revealed that all target compounds exhibited superior inhibitory activity compared to the reference compound PBD150 (140.50 ± 0.93 nM), with compounds A3 (3.36 ± 0.90 nM), A4 (3.20 ± 1.15 nM), B1 (3.99 ± 0.99 nM), and B2 (3.64 ± 0.98 nM) standing out for further investigation. Further, molecular dynamics (MD) simulations were conducted on compounds A3, A4, B1, and B2, revealing the stability and binding interactions of the compounds within the hQC active site over a 200 ns simulation period. Then, the results of binding free energy calculations validated the superior binding affinities of compounds A3, A4, B1, and B2 than PBD150. These findings highlight A3, A4, B1, and B2 as promising hQC inhibitors, offering insights for AD drug development.

Synthesis and biodistribution of a new oxo-technetium-99m bis(aminothiol) complex as a potential melanoma tracer

[123I]-N-(2-Diethylaminoethyl)-4-iodobenzamide (123I-BZA) has been the best scintigraphic agent described so far for malignant melanoma and ocular melanoma diagnosis. We replaced 123I by the more convenient radioisotope 99mTc and synthesized four bis(aminoethanethiol) derivatives. We describe the synthesis of a new oxo-technetium complex (TcO-Cf), prepared in very high yield (radiochemical yield > 95%), that exhibits an affinity for the pigmented tumor cells. This complex was evaluated in vivo in mice bearing C57Bl6 murine melanoma. After injection, a rapid decrease in the radioactivity levels was noted for all tissues and organs except for eyes (1.26 %ID/g at 1 h and 2.69 %ID/g at 24 h postinjection) and the tumor (1.19 %ID/g at 1 h and 0.80 %ID/g at 24 h postinjection), suggesting a specific in vivo binding of this complex to the pigmented cells. These results were compared with those already published for three other technetium-99m bis(aminothiol) complexes with benzamide derivatives.

A potential melanoma tracer: synthesis, radiolabeling, and biodistribution in mice of a new nitridotechnetium bis(aminothiol) derivative pharmacomodulated by a N-(diethylaminoethyl)benzamide

Radioiodobenzamides are the best-known agents under study for the diagnosis of cutaneous melanoma and its metastases. We report the synthesis of a new BAT derivative radiopharmaceutical in which radioiodine is replaced by 99m-technetium. The cyclic intermediary methyl 4-[3-(4,4,7,7-tetramethyl-5,6-dithia-2, 9-diazacyclodecyl)-2-oxapropyl]benzoate (5) occurred in two different conformations identified by spectroscopic analysis. The final BAT ligand was radiolabeled using the nitridotechnetium core by a ligand-exchange reaction. Two different complexes were purified. After macroscopic 99-technetium synthesis, syn and anti isomers were identified. The global radiochemical yield was over 80%. The biodistribution of these two complexes was evaluated in mice bearing murine B16 melanoma. Extensive liver and kidney uptake was observed, but the benzamide tropism for the tumor was partially preserved.