Synthesis of flavonoids based novel tetrahydropyran conjugates (Prins products) and their antiproliferative activity against human cancer cell lines

Unanticipated Bicyclic Etherification in Luche Reduction: Asymmetric Total Syntheses of Diospongins A and B and Tetraketide

In the synthesis of diospongin B based on rearrangement of δ-hydroxyalkynone to 2,3-dihydro-4H-pyran-4-one, we discovered an unanticipated beguiling reaction giving a thermodynamically less stable 4-hydroxy-2,6-trans-disubstituted-THP moiety via bicyclic etherification under Luche reduction conditions and simple acid hydrolysis. The practical applicability of this method is exemplified by the asymmetric total syntheses of diospongins A and B, several analogues, and tetraketide.

Design, synthesis and bioevaluation of novel prenylated chalcones derivatives as potential antitumor agents

A series of novel prenylated chalcone derivatives with broad spectrum anticancer potential were designed and synthesized. Some of the synthesized target compounds showed potent anti-proliferative activities toward LNCaP (prostate cancer cell line), K562 (human leukemia cells), A549 (human lung carcinoma cell line) and HeLa (cervical cancer cell line) cell lines. Among of the active compounds, (E)-1-(4-(2-(diethylamino)ethoxy)-2-hydroxy-6-methoxy-3-(3-methylbut-2-en-1-yl)phenyl)-3-(pyridin-3-yl)prop-2-en-1-one (C36) was directly interacted with protein kinase B (PKB), also known as AKT, significantly inhibited the pPI3K, pAKT(Ser473) protein levels to repress the growth of cancer cells by inducing apoptosis, arresting cell cycle. Our studies provide support for prenylated chalcone derivatives potential applications in cancer treatment as a potential AKT inhibitor.

Asymmetric total synthesis of diosniponols A and B

A concise asymmetric total synthesis of diosniponols A and B has been achieved based on an enantioselective Jacobsen kinetic resolution of racemic epoxide and the important 2,3-dihydro-4H-pyran-4-one moiety being installed by the metal-free δ-hydroxyalkynone rearrangement catalyzed by p-TsOH. A diastereoselective catalytic hydrogenation set the required all-syn stereochemistry leading to diosniponol A, which then, under the Mitsunobu inversion conditions, provided diosniponol B. The structure and absolute stereochemistry of the natural products were further confirmed.

Synthesis and Anticancer Activities of Novel Guanylhydrazone and Aminoguanidine Tetrahydropyran Derivatives

In this paper we present the convenient syntheses of six new guanylhydrazone and aminoguanidine tetrahydropyran derivatives 2-7. The guanylhydrazone 2, 3 and 4 were prepared in 100% yield, starting from corresponding aromatic ketones 8a-c and aminoguanidine hydrochloride accessed by microwave irradiation. The aminoguanidine 5, 6 and 7 were prepared by reduction of guanylhydrazone 2-4 with sodium cyanoborohydride (94% yield of 5, and 100% yield of 6 and 7). The aromatic ketones 8a-c were prepared from the Barbier reaction followed by the Prins cyclization reaction (two steps, 63%-65% and 95%-98%). Cytotoxicity studies have demonstrated the effects of compounds 2-7 in various cancer and normal cell lines. That way, we showed that these compounds decreased cell viabilities in a micromolar range, and from all the compounds tested we can state that, at least, compound 3 can be considered a promising molecule for target-directed drug design.

β-Cyclodextrin in water: highly facile biomimetic one pot deprotection of phenolic THP/MOM/Ac/Ts ethers and concomitant regioselective cyclization of chalcone epoxides and 2′-aminochalcones

A “green” and mild catalytic method for the deprotection of THP/MOM/Ac/Ts ethers and the concomitant cyclizations of epoxy chalcone to 2-hydroxyindanone or 2′-aminochalcone to aza-flavanone are reported.

Microwave-assisted expeditious and efficient synthesis of novel quinolin-4-ylmethoxychromen-2- and -4-ones catalyzed by YbCl3 under a solvent free one-pot three component domino reaction and their antimicrobial activity

MW assisted multicomponent A³ synthesis was developed for the synthesis of quinolin-4-ylmethoxychromen-2- and -4-ones in high yields with YbCl₃ and reused efficiently for four times.

Anti-proliferative activities of flavone–estradiol Stille-coupling adducts and of indanone-based compounds obtained by SnCl4/Zn-catalysed McMurry cross-coupling reactions

Flavone–estradiol adducts and indanophen based tamoxifen analogs are synthesized using SnCl₄–Zn reagent via McMurry reaction and evaluated in human cervical (HeLa) and breast cancer cells (MCF-7 and MDA-MB-231) for the anti-proliferative activity.

Chalcone based azacarboline analogues as novel antitubulin agents: design, synthesis, biological evaluation and molecular modelling studies

The present study involves the design of a series of 3-aryl-9-acetyl-pyridazino[3,4-b]indoles as constrained chalcone analogues. A retrosynthetic route was proposed for the synthesis of target compounds. All the synthesized compounds were evaluated for in-vitro cytotoxicity against THP-1, COLO-205, HCT-116 and A-549 human cancer cell lines. The results indicated that 2a, 3a, 5a and 6a possessed significant cytotoxic potential with an IC50 value ranging from 1.13 to 5.76 μM. Structure activity relationship revealed that the nature of both Ring A and Ring B influences the activity. Substitution of methoxy groups on the phenyl ring (Ring A) and unsubstituted phenyl ring (Ring B) were found to be the preferred structural features. The most potent compound 2a was further tested for tubulin inhibition. Compound 2a was found to significantly inhibit the tubulin polymerization (IC50 value - 2.41 μM against THP-1). Compound 2a also caused disruption of microtubule assembly as evidenced by Immunoflourescence technique. The significant cytotoxicity and tubulin inhibition by 2a was rationalized by molecular modelling studies. The most potent structure was docked at colchicine binding site (PDB ID-1SA0) and was found to be stabilized in the cavity via various hydrophobic and hydrogen bonding interactions.