Synthesis and cytotoxic evaluation of novel indenoisoquinoline-substituted triazole hybrids.

The synthesis of various substituted triazole-indenoisoquinoline hybrids was performed based on a CuI-catalyzed 1,3-cycloaddition between propargyl-substituted derivatives and the azide-containing indenoisoquinoline. Besides, a variety of N-(alkyl)propargylindenoisoquinolines was used as substrates for the construction of triazole-indenoisoquinoline-AZT conjugated via a click chemistry-mediated coupling with 3'-azido-3'-deoxythymidine (AZT). Thus, twenty three new indenoisoquinoline-substituted triazole hybrids were successfully prepared and evaluated as cytotoxic agents, revealing an interesting anticancer activity of four triazole linker-indenoisoquinoline-AZT hybrids in KB and HepG2 cancer cell lines.

Synthesis and anticancer properties of new (dihydro)pyranonaphthoquinones and their epoxy analogs.

1,4-Dihydroxy-2-naphthoic acid was used as a substrate for a straightforward five-step synthesis of 3-substituted 1H-benzo[g]isochromene-5,10-diones, with a Michael addition of N-acylmethylpyridinium ylides across 2-hydroxymethyl-1,4-naphthoquinone and a subsequent acid-mediated dehydratation of intermediate hemiacetals as the key steps. The obtained benzo[g]isochromene-5,10-diones were subsequently deployed for further synthetic elaboration to produce new 3,4-dihydrobenzo[g]isochromene-5,10-diones and (3,4-dihydro-)4a,10a-epoxybenzo[g]isochromene-5,10-diones. All compounds were screened for their cytotoxic and antimicrobial effects, revealing an interesting cytotoxic activity of 1H-benzo[g]isochromene-5,10-diones against different cancer cell lines.

Synthesis and cytotoxic evaluation of novel ester-triazole-linked triterpenoid-AZT conjugates.

Betulinic acid and analogous naturally occurring triterpenoid acids were transformed into the corresponding propargyl esters and subsequently deployed as substrates for a click chemistry-mediated coupling with azidothymidine (AZT) en route to novel 1,2,3-triazole-tethered triterpenoid-AZT conjugates. Twelve new hybrids were thus prepared and assessed in terms of their cytotoxic activity, revealing an interesting anticancer activity of five triterpenoid-AZT hybrids on KB and Hep-G2 tumor cell lines.

Synthesis of new bioisosteric hemiasterlin analogues with extremely high cytotoxicity.

In this Letter, the synthesis and the evaluation of the cytotoxicity of new hemiasterlin analogues were reported. The indole moiety was replaced respectively by benzofurane, naphthalene and 4-bromobenzene groups. Most of these derivatives possess strong cytotoxic activity on two human tumour cell lines (KB and Hep-G2), and some analogues showed comparable cytotoxic activity to that observed for paclitaxel and ellipticine, against KB and Hep-G2 cancer cell lines.

Nucleophile-directed selective transformation of cis-1-tosyl-2-tosyloxymethyl-3-(trifluoromethyl)aziridine into aziridines, azetidines, and benzo-fused dithianes, oxathianes, dioxanes, and (thio)morpholines.

A five-step procedure for the synthesis of cis-1-tosyl-2-tosyloxymethyl-3-(trifluoromethyl)aziridine was developed, starting from 1-ethoxy-2,2,2-trifluoroethanol, involving imination, aziridination, ester reduction, hydrogenation, and N-,O-ditosylation steps. Further synthetic elaborations revealed a remarkable difference in the reactivity of cis-1-tosyl-2-tosyloxymethyl-3-(trifluoromethyl)aziridine with respect to aromatic sulfur and oxygen nucleophiles, thus enabling the selective deployment of this versatile substrate as a building block for the synthesis of functionalized aziridines, azetidines, and benzo-fused dithianes, oxathianes, dioxanes, and (thio)morpholines.

Synthesis of 1-alkyl-2-(trifluoromethyl)azetidines and their regiospecific ring opening toward diverse α-(trifluoromethyl)amines via intermediate azetidinium salts.

A convenient approach toward nonactivated 1-alkyl-2-(trifluoromethyl)azetidines as a new class of constrained azaheterocycles was developed starting from ethyl 4,4,4-trifluoroacetoacetate via imination, hydride reduction, chlorination, and base-induced ring closure. Furthermore, the reactivity profile of these 2-CF(3)-azetidines was assessed by means of quaternization and subsequent regiospecific ring opening at C4 of the azetidinium intermediates by oxygen, nitrogen, carbon, sulfur, and halogen nucleophiles, pointing to a clear difference in reactivity compared to azetidines bearing other types of electron-withdrawing groups at C2.