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Abstract: Truncated phosphonated C-1′-branched N,O-nucleosides have been synthesized in good yields by 1,3-dipolar cycloaddition methodology, starting from N-methyl-C-(diethoxyphosphoryl)nitrone 7. Preliminary biological assays show that β-anomers are able to inhibit HIV in vitro infection at concentrations in the micromolar range. Higher SI values with respect to AZT indicated that the compounds were endowed with low cytotoxicity. [Copyright &y& Elsevier]

Abstract: An efficient biocatalytic procedure to obtain chiral N,O-nucleoside derivatives consisting of a lipase-catalysed resolution of the corresponding racemates in organic solvent has been developed. Enantioselective esterification of thymine and cytosine derivatives, (±)-9a and (±)-9b, has been investigated by comparing the efficiency of different lipases and acyl donors. Since esterification of (±)-9a and (±)-9b, occurred with low enantioselectivity (E ⩽14) in the presence of the lipases considered, for preparative purposes we resorted, with success, to a double sequential kinetic resolution, using Lipozyme IM as the best catalyst. This approach enables us to obtain all the enantiomers with ee⩾95%. The absolute configuration of the new chiral N-acetyl cytosine derivative 9b was established by circular dichroism spectroscopy. [Copyright &y& Elsevier]

Abstract: A general, practical, and efficient reduction of four-, five-, six- and, seven-membered N-alkoxycarbonyl lactams to the aldehyde oxidation state is reported. The reduction methodology involves the hydrozirconation reaction by Cp2Zr(H)Cl under mild conditions and proceeds with very short reaction times and in excellent to good yields. The hydrozirconation of N-alkoxycarbonyl lactams with the Schwartz reagent demonstrated to be the mildest and most general method for the formation of lactamols with a high functional group tolerance. [Copyright &y& Elsevier]

Abstract: A synthetic approach towards a series of 3-hydroxymethyl-5-(1H-1,2,3-triazol)isoxazolidines has been reported, according to a procedure based on the cycloaddition reaction, under microwave irradiation, of a nitrone with 1-vinyl triazoles, prepared by a click reaction of azides with alkynes. Biological tests show that the synthesized compounds are able to inhibit proliferation of follicular and anaplastic human thyroid cancer cell lines, with IC50 values ranging from 3.87 to 8.76μM. The obtained compounds induce caspase-3 activation and DNA fragmentation prevalently in follicular human thyroid cancer cell lines. [Copyright &y& Elsevier]

Abstract: The third generation of isoxazole polycyclic aromatic hydrocarbons, acting as DNA-intercalator agents and possessing the binding constants in the range 104–105 M−1, in order to easily diffuse targeting remotely implanted tumors, has been synthesized in good yields according to the 1,3-dipolar cycloaddition methodology. The structure of the obtained cycloadducts has been determined by NOE experiments and supported by computational studies at PM3 level. All the obtained compounds have been tested for their in vitro cytotoxic activity and the most potent of them, (3RS,5SR)-2-benzyl-N,N-dimethyl-3-(pyren-1-yl)isoxazolidine-5-carboxamide (7d), showed an IC50 of 4 μM upon the human lung cancer (A-549) cells. Moreover, compound 7d showed binding constant for the intercalation with calf thymus DNA, poly-d(AT)2 and poly-d(GC)2 of 1.7 × 105 M−1, 1.6 × 105 M−1 and 0.3 × 105 M−1, respectively. Biological and docking studies showed that, in vitro, these compounds complex by intercalation between base pairs, approaching the DNA from its minor groove with a preference for the AT nucleobases pairs. [Copyright &y& Elsevier]

Abstract: Arenediyne–isoxazolidine conjugates have been synthesized as a new scaffold for the development of bioactive mimics. Some of the synthesized compounds are endowed with antiproliferative activity against three human cancer cell lines. Their thermal reactivity suggests that the biological activity probably could not be linked to the Bergman cyclization. [Copyright &y& Elsevier]

Abstract: Herein we report the synthesis of a series of novel constrained peptidomimetics 2–10 endowed with a dipeptide backbone (d-Ser-Gly) and a vinyl ester warhead, structurally related to a previously identified lead compound 1, an irreversible inhibitor of falcipain-2, the main haemoglobinase of lethal malaria parasite Plasmodium falciparum. The new compounds were evaluated for their inhibition against falcipain-2, as well as against cultured P. falciparum. The inhibitory activity of the synthesized compounds was also evaluated against another protozoal cysteine protease, namely rhodesain of Trypanosoma brucei rhodesiense. [Copyright &y& Elsevier]