Scope and limitations of the synthesis of functionalized quinolizidinones and related compounds by a simple precursor approach via addition of lithium allylmagnesates to 2-pyridones and RCM as key steps

Synthesis and Anticancer Activity of Mitotic-Specific 3,4-Dihydropyridine-2(1H)-thiones

Most anticancer drugs target mitosis as the most crucial and fragile period of rapidly dividing cancer cells. However the limitations of classical chemotherapeutics drive the search for new more effective and selective compounds. For this purpose structural modifications of the previously characterized pyridine aalog (S1) were incorporated aiming to obtain an antimitotic inhibitor of satisfactory and specific anticancer activity. Structure-activity relationship analysis of the compounds against a panel of cancer cell lines allowed to select a compound with a thiophene ring at C5 of a 3,4-dihydropyridine-2(1H)-thione (S22) with promising antiproliferative activity (IC50 equal 1.71 ± 0.58 µM) and selectivity (SI = 21.09) against melanoma A375 cells. Moreover, all three of the most active compounds from the antiproliferative study, namely S1, S19 and S22 showed better selectivity against A375 cells than reference drug, suggesting their possible lower toxicity and wider therapeutic index. As further study revealed, selected compounds inhibited tubulin polymerization via colchicine binding site in dose dependent manner, leading to aberrant mitotic spindle formation, cell cycle arrest and apoptosis. Summarizing, the current study showed that among obtained mitotic-specific inhibitors analogue with thiophene ring showed the highest antiproliferative activity and selectivity against cancer cells.

Visible-light-promoted selective O-alkylation of 2-pyridones with α-aryldiazoacetates

A visible-light-promoted O-H insertion reaction between 2-pyridones and α-aryldiazoacetates has been developed. Upon visible light irradiation, the reaction proceeds smoothly under mild and catalyst-free conditions. A wide scope of 2-pyridones and α-aryldiazoacetates are well tolerated, and various O-alkylated 2-pyridones are obtained with perfect selectivity and good functional group tolerance. A photoinduced radical process is probably responsible for the excellent selectivity.

Arylation of enelactams using TIPSOTf: reaction scope and mechanistic insight

Triisopropylsilyltrifluoromethanesulfonate can be effectively used for the arylation of a wide range of enelactams. The multinuclear NMR study provided deep insights into the reaction mechanism.

Magnesiate-Utilized/Benzyne-Mediated Approach to Indenopyridones from 2-Pyridones: An Attempt To Synthesize the Indenopyridine Core of Haouamine

An efficient, short-staged synthesis of cis-fused indeno[2,1-b]- and indeno[1,2-c]pyridin-2-ones, starting from 2-pyridones, using magnesiates of type R₃MgLi as nucleophilic and deprotonation agents, mediated by benzyne generated in situ, under optimized conditions, is described. Following the developed protocol, rare C4a-arylsubstituted indeno[2,1-b]pyridones, resembling the core of haouamine, were obtained. The protocol offering the one-pot synthesis directly from 2-pyridone is also described.

Diversity-Oriented Synthesis toward Fused and Bridged Benzobicyclic Piperidin(on)es

An efficient diverse synthesis of cis-fused indenopiperidines and bridged benzomorphanones, starting from cyclopropane-fused benzomorphanothiones and benzomorphanones, respectively, using NaBH₄/NiCl₂·6H₂O/EtOH as a reducing system, is described. High rigidity of substrates allowed axially controlled syntheses of their trans-mono-alkylated derivatives, subsequently enabling access to both trans-alkyl-functionalized benzobicyclic piperidin(on)es. Diversity-oriented synthesis of naphthalene ring-containing fused naphthoindenopiperidines and bridged naphthomorphanone directly from 2-pyridones was also performed.

Comparative evaluation of new dihydropyrimidine and dihydropyridine derivatives perturbing mitotic spindle formation

AIM

The mitotic spindle plays a key role in cell division which makes it an important target in cancer therapy. In the present study the antiproliferative activity of 4-benzyl-5-phenyl-3,4-dihydropyrimidine-2(1H)-thione (1) and its pyridine bioisoster (2) were evaluated and compared with monastrol (MON), the first known cell-permeable small molecule which disrupts bipolar spindle formation by inhibiting Eg5-kinesin activity.

RESULTS

Our data revealed that compound 2 showed higher antiproliferative activity than MON against MCF7 and A375 cell lines and comparable reversible cell cycle inhibition in G2/M phase. However, compound 2 produced distinct phenotype from monoastral spindles, and did not affect Eg5 ATPase activity.

CONCLUSION

The activity of compound 2 may suggest its new promising anticancer mechanism (different than MON), targeting other component required for spindle bipolarity.

Specific N-Alkylation of Hydroxypyridines Achieved by a Catalyst- and Base-Free Reaction with Organohalides

A specific N-alkylation of 2-hydroxypyridines is achieved by reacting with organohalides under catalyst- and base-free conditions. The observed HX-facilitated conversion of pyridyl ether intermediates to 2-pyridone products may account for the success and specific N-alkylation of the reaction under the unexpectedly simple conditions. This new reaction may provide a useful alternative for the synthesis of 2-pyridones and analogous structures because of its >99% N-selectivity, relatively broad scopes of both substrates, and no mandatory use of catalysts and bases.