New N(4)-substituted piperazine naphthamide derivatives as BACE-1 inhibitors.

Synthesis and enzymatic evaluation of new series of N(4)-substituted piperazine naphthamide derivatives as BACE-1 inhibitors for the treatment of Alzheimer's disease are reported.

New bicyclam-AZT conjugates: design, synthesis, anti-HIV evaluation, and their interaction with CXCR-4 coreceptor.

We report the synthesis of mono- and bis-tetraazamacrocycle-AZT conjugates. All new compounds were screened for their ability to inhibit HIV-1 replication in MT4 cell line and were compared to AZT alone. It appears that N-protected covalent prodrugs are equipotent to AZT as inhibitor of HIV replication, while N-deprotected analogues exhibit both higher activity and selectivity against HIV-infected cells. The most active antiviral compounds 27, 28, 34, and 35 were then tested for their binding capability to CXCR-4 receptor. N-Boc analogues 27 and 34 were only weakly effective; in contrast, N-deprotected conjugates 28 and 35 were antagonists to 12G5 mAb binding until 0.05 and 5 microg/mL, respectively. The stability of compound 28 in human plasma was evaluated, and half-life was found to be approximately 8 h in the described conditions. All these results seem to demonstrate the confidence of our prodrug approach, with analogue 28 emerging as the best candidate as lead compound in HIV-1 polytherapy perspective.

Design, synthesis and structure relationships of new N,N',N",N"'-tetrakis (omega-amino alkyl) tetraazamacrocycles.

A number of N,N',N",N"'-tetrakis (omega-aminoalkyl) tetraazamacrocycles and related compounds were synthesized and evaluated for their inhibitory effects on human immunodeficiency virus type 1 (HIV-1) and duck hepatitis B virus (DHBV) replication. The activity of these compounds was found to be highly dependent upon structural features: (i) the length of the alkyl linker connecting the nitrogen atoms of the macrocyclic ring to the exocyclic nitrogen atoms of the terminal amino groups (five methylenes favoured antiviral activity); (ii) substitution of the terminal amino groups of the linker reduced antiviral activity; and (iii) the size of the tetraazamacrocyclic ring (14 or 15 atoms) did not markedly affect the antiviral activity. Some analogues were potent inhibitors of HIV-1 replication, with anti-HIV activity similar to that of biscyclam (JM 2763). In contrast, other analogues were found to be highly toxic in duck hepatocyte primary culture, the 2.2.15 cell line and to a lesser extent in MT-4 cells. Structural parameters, macrocyclic ring size and metal-chelating ability have been used to develop a structure-activity relationship model in order to aid the design of antiviral molecules derived from N,N',N",N"'-tetrakis (omega-aminoalkyl) tetraazamacrocycles.

New polyazamacrocycle-nucleoside conjugates: synthesis, anti-HIV evaluation and interaction with CXCR-4 coreceptor.

We report the synthesis of new conjugates that incorporate in their structure bis-tetraazamacrocycle coupled with AZT via enzymolabile bond. Two series of bis-polyazamacrocycles-AZT conjugates were designed, synthesized and evaluated for their antiviral effect in vitro as well as their capability to bind to CXCR-4 coreceptor.

Tri-N-Boc-tetraazamacrocycle-nucleoside conjugates: synthesis and anti-HIV activities.

As far as linear N-Boc-polyamines conjugates elicited remarkable anti-HIV activity, the synthesis and anti-HIV properties of cyclic N-Boc-polyamines conjugates such as tetraazamacrocycle-nucleoside were studied. These new conjugates include an ester linkage between the two moieties. They were synthesized using Benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate coupling reagent, in the case of N-alkyl polyazamacrocycle derivatives, or through direct condensation of the acyl chloride derivative with nucleoside in the case of N-acyl polyazamacrocycle compounds. None of the new conjugates presented anti-HIV activity greater than that of the corresponding parent nucleosides.

Selective inhibition of the duck hepatitis B virus by a new class of tetraazamacrocycles.

The antiviral activity of a new class of N,N,N',N",NA'''-pentakis (omega-aminoalkyl) tetraazamacrocycles was evaluated in primary duck hepatocyte cultures infected with the duck hepatitis B virus (DHBV). Three of the four tested compounds were able to selectively inhibit DHBV replication by acting at an early step of the hepadnavirus infection but were associated with significant toxicity.