A perspective on the application of macrocyclic design strategies in antitumor drugs.

The macrocyclization of inhibitors has become gradually favored as a new approach for drug design in the field of anticancer agents, since the recent approvals of lorlatinib, pacritinib, and repotrectinib, and feasibility of macrocyclic modification to improve inhibitor drug-like properties has also been confirmed. Macrocycles are receiving increasing attention due to their enhanced binding affinity, target selectivity, and pharmacokinetic properties through conformational constraints. Therefore, this review summarizes various strategies for improving drug-like properties in macrocyclization and structural optimization, and reveals that macrocyclization is a new favorable strategy for drug design, aiming to provide insights for the drug discovery in different targets.

Design, synthesis, and biological evaluation of N-(pyridin-3-yl)pyrimidin-4-amine analogues as novel cyclin-dependent kinase 2 inhibitors for cancer therapy.

The discovery and development of CDK2 inhibitors has currently been validated as a hot topic in cancer therapy. Herein, a series of novel N-(pyridin-3-yl)pyrimidin-4-amine derivatives were designed and synthesized as potent CDK2 inhibitors. Among them, the most promising compound 7l presented a broad antiproliferative efficacy toward diverse cancer cells MV4-11, HT-29, MCF-7, and HeLa with IC values of 0.

Synthesis and biological evaluation of novel 5-substituted/unsubstituted triazolothiadiazines as tubulin depolymerizing and vascular disrupting agents with promising antitumor activity.

A novel series of 5-substituted/unsubstituted [1,2,4]triazolo[3,4-b][1,3,4] thiadiazine compounds has been achieved successfully through chemoselective reduction of the C = N bond, based on our prior work. Initial biological evaluation illustrated that the most active derivative 7j exhibited significant cell growth inhibitory activity toward MCF-7, A549, HCT116, and A2780 with the IC values of 0.75, 0.

Rational design, synthesis and biological evaluation of novel 2-(substituted amino)-[1,2,4]triazolo[1,5-a]pyrimidines as novel tubulin polymerization inhibitors.

Following our previously reported compound 3, we designed and synthesized a series of new 2-(substituted amino)- [1,2,4]triazolo[1,5-a]pyrimidines as potential tubulin polymerization inhibitors. Among them, analogue 4k, having a 3-hydroxy-4-methoxyphenylamino group, was observed to display excellent antiproliferative activity toward HeLa, HCT116, A549, and T47D with the IC values of 0.31, 1.

Efficient synthesis and evaluation of novel 6-arylamino-[1,2,4]triazolo[4,3-a]pyridine derivatives as antiproliferative agents.

Based on our previous work, a series of novel 6-arylamino-[1,2,4]triazolo[4,3-a]pyridine derivatives were synthesized, and evaluated for antiproliferative activities. SAR studies revealed that inserting an amino linkage between 6‑aryl group and [1,2,4]triazolo[4,3-a]pyridine core led to amuch broaderantitumorspectrum, and the most promising compound 8 l exerted potent andbroad-spectrum antiproliferative activity toward HeLa, HCT116, MCF-7, and A549 cell lines, with IC values in the micromolar range of 5.98-12.

1,4-Dihydropyridinebutyrolactone-derived ring-opened ester and amide analogs targeting BET bromodomains.

Based on a previously reported 1,4-dihydropyridinebutyrolactone virtual screening hit, nine lactone ring-opened ester and seven amide analogs were prepared. The analogs were designed to provide interactions with residues at the entrance of the ZA loop of the testis-specific bromodomain (ZA) channel to enhance the affinity and selectivity for the bromodomain and extra-terminal (BET) subfamily of bromodomains. Compound testing by AlphaScreen showed that neither the affinity nor the selectivity of the ester and lactam analogs was improved for BRD4-1 and the first bromodomain of the testis-specific bromodomain (BRDT-1).

Concise synthesis and preliminary biological evaluation of new triazolylthioacetone derivatives bearing pyridine, pyrazine, and 3,4,5-trimethoxybenzyl fragment.

Based on our previous work, a series of novel triazolylthioacetones incorporating pyridine, pyrazine, and 3,4,5-trimethoxybenzyl fragment were synthesized, and evaluated for antiproliferative activities and interactions with tubulin. Some analogues exhibited moderate to excellent potency, with the most promising compound IIc possessing IC values of 0.62, 1.

Development of pteridin-7(8H)-one analogues as highly potent cyclin-dependent kinase 4/6 inhibitors: Synthesis, structure-activity relationship, and biological activity.

CDK4/6 have been validated as the cancer therapeutic targets. Here, we describe a series of pteridin-7(8H)-one analogues as potent CDK4/6 inhibitors. Among them, the most promising compound 7s demonstrated remarkable and broad-spectrum antiproliferative activities toward HCT116, HeLa, MDA-MB-231, and HT-29 cells with IC values of 0.

Design, synthesis and antiproliferative activity of novel 2,4-diamino-5-methyleneaminopyrimidine derivatives as potential anticancer agents.

In order to discover new anticancer agents, 25 novel 2,4-diamino-5-methyleneaminopyrimidine derivatives were designed and synthesized based on our previous work via a ring-opening strategy. Among them, compared with 5-FU, compound 7i exhibited 4.9-, 2.

Discovery of highly potent tubulin polymerization inhibitors: Design, synthesis, and structure-activity relationships of novel 2,7-diaryl-[1,2,4]triazolo[1,5-a]pyrimidines.

By removing 5-methyl and 6-acetyl groups in our previously reported compound 3, we designed a series of novel 2,7-diaryl-[1,2,4]triazolo[1,5-a]pyrimidine derivatives as potential tubulin polymerization inhibitors. Among them, compound 5e displayed low nanomolar antiproliferative efficacy on HeLa cells which was 166-fold higher than the lead analogue 3. Interestingly, 5e displayed significant selectivity in inhibiting cancer cells over HEK-293 (normal human embryonic kidney cells).

Synthesis, biological evaluation, and structure-activity relationships of new tubulin polymerization inhibitors based on 5-amino-1,2,4-triazole scaffold.

Based on our previous research, thirty new 5-amino-1H-1,2,4-triazoles possessing 3,4,5-trimethoxyphenyl moiety were synthesized, and evaluated for antiproliferative activities. Among them, compounds IIa, IIIh, and IIIm demonstrated significant antiproliferative activities against a panel of tumor cell lines, and the promising compound IIIm dose-dependently caused G2/M phase arrest in HeLa cells. Furthermore, analogue IIa exhibited the most potent tubulinpolymerization inhibitory activity with an IC value of 9.

Synthesis and antiproliferative evaluation of novel 8-cyclopentyl-7,8-dihydropteridin-6(5H)-one derivatives as potential anticancer agents.

Based on our previous work, a novel class of 8-cyclopentyl-7,8-dihydropteridin-6(5H)-one derivatives were synthesized and evaluated as antiproliferative agents. Structure-activity relationship analysis revealed that the greatest activities were achieved with a 4-(4-methylpiperazin-1-yl)aniline group at C-2 position of dihydropteridin-6(5H)-one core, and the most promising compound 6k demonstrated comparable antiproliferative activity with Palbociclib and more potent than our parent derivative 4 toward four cell lines including HCT-116, HeLa, HT-29, and MDA-MB-231 with IC values of 3.29, 6.

Synthesis, and biological evaluation of 3,6-diaryl-[1,2,4]triazolo[4,3-a]pyridine analogues as new potent tubulin polymerization inhibitors.

On the basis of our previous work, twenty-nine novel [1,2,4]triazolo[4,3-a]pyridines possessing 3,4,5-trimethoxylphenyl groups were designed, synthesized, and evaluated as tubulin polymerization inhibitors. The bioassay results revealed that some of the compounds displayed excellent antiproliferative efficacies in the nanomolar range against HeLa cells, and the most promising derivative 7i demonstrated almost comparable activity to that of the reference CA-4 and sixty-two fold more potent than the parent compound 6 with an IC value of 12 nM. Importantly, 7i exhibited high selectivity over the normal human embryonic kidney HEK-293 cells (IC > 100 μM).

Synthesis and biological evaluation of benzofuran-based 3,4,5-trimethoxybenzamide derivatives as novel tubulin polymerization inhibitors.

A new series of derivatives characterized by the presence of the 3,4,5-trimethoxylbenzamide substituted benzofurans were synthesized and evaluated for antiproliferative activity against four cancer cell lines and one normal human cell line. Among them, derivative 6g with greatest cytotoxicity significantly inhibited the growth of MDA-MB-231, HCT-116, HT-29 and HeLa cell lines with IC values of 3.01, 5.

Synthesis and biological evaluation of novel pyrazolo[3,4-b]pyridines as cis-restricted combretastatin A-4 analogues.

Twenty-six novel pyrazolo[3,4-b]pyridine-bridged analogues of combretastatin A-4 possessing 3,4,5-trimethoxylphenyl groups, were synthesized and evaluated for their antiproliferative and tubulin polymerization inhibitory activities. Preliminary biological evaluation demonstrated that some of the target compounds displayed significant antiproliferative effectagainst four different cell lines including MCF-7, MDA-MB-231, HeLa and Kyse150. The most active analogue 6n was found to induce HeLa cells arrest in the G2/M phase in a dose-dependent manner.

Design, synthesis and biological evaluation of novel indole-based oxalamide and aminoacetamide derivatives as tubulin polymerization inhibitors.

A series of novel indole-based oxalamide and aminoacetamide derivatives were designed, synthesized, and evaluated for antiproliferative activities. Preliminary results revealed that compound 8g exhibited significant antiproliferative effect against PC-3, HeLa and HCT-116 cell lines. Flow cytometric analysis of the cell cycle demonstrated the compound 8g induced the cell cycle arrest at G2/M phase in HeLa cell lines.

Novel [1,2,4]triazolo[1,5-a]pyrimidine derivatives as potent antitubulin agents: Design, multicomponent synthesis and antiproliferative activities.

As restricted CA-4 analogues, a novel series of [1,2,4]triazolo[1,5-a]pyrimidines possessing 3,4,5-trimethoxylphenyl groups has been achieved successfully via an efficient one-pot three-component reaction of 3-(3,4,5-trimethoxyphenyl)-1H-1,2,4-triazol-5-amine, 1,3-dicarbonyl compounds and aldehydes. Initial biological evaluation demonstrated some of target compounds displayed potent antitumor activity in vitro against three cancer cell lines. Among them, the most highly active analogue 26 inhibited the growth of HeLa, and A549 cell lines with IC values at 0.

Discovery of novel pyrimidine-based benzothiazole derivatives as potent cyclin-dependent kinase 2 inhibitors with anticancer activity.

To develop novel CDK2 inhibitors as anticancer agents, a series of novel pyrimidine-based benzothiazole derivatives were designed and synthesized. Initial biological evaluation demonstrated some of target compounds displayed potent antitumor activity in vitro against five cancer cell lines. Especially, the analogue 10s exhibited approximately potency with AZD5438 toward four cells including HeLa, HCT116, PC-3, and MDA-MB-231 with IC values of 0.

Facile one-pot synthesis, antiproliferative evaluation and structure-activity relationships of 3-amino-1H-indoles and 3-amino-1H-7-azaindoles.

A highly efficient method has been developed for the one-pot synthesis of substituted 3-amino-1H-indole and 3-amino-1H-7-azaindole derivatives starting from ethyl 2-cyanophenylcarbamate/ethyl 3-cyanopyridin-2-ylcarbamate, and α-bromoketones in good to excellent yields. All newly synthesized analogues were screened for their antiproliferative activities against four cancer cell lines. The most promising compound 8v demonstrated 13-, 5-, and 1.

Synthesis, biological evaluation, and molecular docking investigation of 3-amidoindoles as potent tubulin polymerization inhibitors.

A series of novel 3-amidoindole derivatives possessing 3,4,5-trimethoxylphenyl groups were synthesized and evaluated for their antiproliferative and tubulin polymerization inhibitory activities. Some of them demonstrated moderate to potent activities in vitro against six cancer cell lines including MCF-7, MDA-MB-231, BT549, T47D, MDA-MB-468, and HS578T. The most active compound 27 inhibited the growth of T47D, BT549, and MDA-MB-231 cell lines with IC values at 0.

Discovery and optimization of 3,4,5-trimethoxyphenyl substituted triazolylthioacetamides as potent tubulin polymerization inhibitors.

Based on our previous research, three series of new triazolylthioacetamides possessing 3,4,5-trimethoxyphenyl moiety were synthesized, and evaluated for antiproliferative activities and inhibition of tubulin polymerization. The most promising compounds 8b and 8j demonstrated more significant antiproliferative activities against MCF-7, HeLa, and HT-29 cell lines than our lead compound 6. Moreover, analogues 8f, 8j, and 8o manifested more potent antiproliferative activities against HeLa cell line with IC values of 0.

Design, synthesis and antiproliferative activity of novel substituted 2-amino-7,8-dihydropteridin-6(5H)-one derivatives.

Based on our previous work, a series of novel 2-amino-7,8-dihydropteridin-6(5H)-one derivatives were designed and synthesized via a ring-closing strategy. Biological evaluation with four human cancer cell lines (BT549, T47D, MDA-MB-468, and MDA-MB-231) showed that most of these compounds possessed moderate to potent antiproliferative activities. The most promising compound 8-benzyl-2-(phenethylamino)-7,8-dihydropteridin-6(5H)-one (6q) possessing IC values of 7.

Synthesis and biological evaluation of novel indole-pyrimidine hybrids bearing morpholine and thiomorpholine moieties.

Based on our previous screening hit compound 1, a series of novel indole-pyrimidine hybrids possessing morpholine or thiomorpholine moiety were synthesized via an efficient one-pot multistep synthetic method. The antiproliferative activities of the synthesized compounds were evaluated in vitro against four cancer cell lines including HeLa, MDA-MB-231, MCF-7, and HCT116. The results revealed that most compounds possessed moderate to excellent potency.

Design, synthesis, and biological evaluation of novel alkylsulfanyl-1,2,4-triazoles as cis-restricted combretastatin A-4 analogues.

Thirty-two novel 3-alkylsulfanyl-1,2,4-triazole derivatives, designed as cis-restricted combretastatin A-4 analogues, were synthesized and evaluated for their antiproliferative activities. The results indicated that analogue 20 showed more potent antiproliferative activities against PC-3 cell lines than positive control CA-4. Particularly, the most promising compound 25 displayed 5-fold improvement compared to CA-4 in inhibiting HCT116 cell proliferation with IC values of 1.