SYNTHESIS OF 2,4(1H,3H)-QUINAZOLINEDIONE AND 3-SUBSTITUTED 2,4(1H,3H)-QUINAZOLINEDIONES

Quinazolinone dimers as a potential new class of safer Kv1 inhibitors: Overcoming hERG, sodium and calcium channel affinities

The discovery of more selective and safer voltage-gated potassium channel blockers is an extremely demanding approach. Designing selective Kv1.5 inhibitors is very challenging as only limited data is available on this target due to a lacking crystal structure for this ion channel receptor. Herein, we synthesized a series of 21 novel quinazolinone dimers 3a-i, 5a-i and 10a-c. We tried to avoid structural features responsible for non-selectivity and for most potassium channel blockers' side effects in our design. In contrast to other works, which lack investigation over wide ranges of potassium and sodium channels, we screened the inhibitory activity of our synthesized compounds over multiple voltage-gated potassium channels, including six different human Kv1 channel subtypes Kv1.1, Kv1.2, Kv1.3, Kv1.4, Kv1.5 and Kv1.6 channels as well as Kv2.1, Kv3.1, Kv4.3, Kv7.2, Kv7.3, Kv10.1, hERG, and Shaker IR. Moreover, these compounds' selectivity was investigated on sodium channels Nav1.2, Nav1.4 and Nav1.5 and calcium channels Cav3.1-Cav3.3. The results revealed two compounds (3a and 3e) with low micromolar Kv1.5 inhibition activity with EC₅₀ values of 5.1 ± 0.9 µM and 12.5 ± 1.1 µM, respectively. However, at higher concentrations, they also showed inhibitory activity on Kv1.3 and Kv1.1 channels. This might be due to structural similarities between these three Kv1 channel isoforms. Compound 3a shows a slight preference for Kv1.5. Interestingly, they lack any activity on other potassium channels (including hERG), sodium channels, and calcium channels. Our findings recommend quinazolinone dimers with ethylene linker as a potential new class of safer Kv1 inhibitors and a good start for designing more selective and potent Kv1.5 inhibitors.

Synthesis, 2D-QSAR Studies and Biological Evaluation of Quinazoline Derivatives as Potent Anti-Trypanosoma cruzi Agents

BACKGROUND

Chagas disease affects about 7 million people worldwide. Only two drugs are currently available for the treatment for this parasite disease, namely, benznidazol (Bzn) and nifurtimox (Nfx). Both drugs have limited curative power in the chronic phase of the disease. Therefore, continuous research is an urgent need so as to discover novel therapeutic alternatives.

OBJECTIVE

The development of safer and more efficient therapeutic anti-T. cruzi drugs continues to be a major goal in trypanocidal chemotherapy.

METHOD

Synthesis, 2D-QSAR and drug-like physicochemical properties of a set of quinazolinone and quinazoline derivatives were studied as trypanocidal agents. All compounds were screened in vitro against Trypanosoma cruzi (Tulahuen strain, Tul 2 stock) epimastigotes and bloodstream trypomastigotes.

RESULTS

Out of 34 compounds synthesized and tested, six compounds (5a, 5b, 9b, 9h, 13f and 13p) displayed significant activity against both epimastigotes and tripomastigotes, without exerting toxicity on Vero cells.

CONCLUSION

The antiprotozoal activity of these quinazolinone and quinazoline derivatives represents an interesting starting point for a medicinal chemistry program aiming at the development of novel chemotherapies for Chagas disease.