Synthesis and structure–activity analysis of diphenylpyrazolodiazene inhibitors of the HIV-1 Nef virulence factor

Abstract

HIV-1 Nef is a critical AIDS progression factor yet underexplored target for antiretroviral drug discovery. A recent high-throughput screen for pharmacological inhibitors of Nef-dependent Src-family kinase activation identified a diphenylpyrazolodiazene hit compound with submicromolar potency in HIV-1 replication assays against a broad range of primary Nef variants. This compound, known as ‘B9’, binds directly to Nef and inhibits is dimerization in cells as a possible mechanism of action. Here were synthesized a diverse set of B9 analogs and identified structural features essential to antiretroviral activity. Chemical modifications to each of the three rings present in the parent compound were identified that did not compromise antiviral action. These analogs will guide the development of next-generation compounds with appropriate pharmacological profiles for assessment of antiretroviral activity in vivo.

Construction of Multifunctionalized Azopyrazoles by Silver‐ Catalyzed Cascade Reaction of Diazo Compounds

“…[13] They exhibited ab road spectrum of biologicalp roperties such as antibacterial, [14] antifungal [15] and HIV-1 inhibitory activities. [16] In addition to pyrazoles,s everal methodsf or the synthesis of azopyra- zoles have been reported. [17] Most of these methods involve harsh operationsa nd multistep procedures throughr eactions of aryldiazonium salts with b-keto estersf ollowed by pyrazole formationu sing hydrazines.…”

Iodine-mediated construction of polyfunctionalized arylazopyrazoles from β-ketoesters or 2-arylpyrazol-3-ones and arylhydrazines

“…1). 13 Recently, arylazopyrazoles have been widely used as important photoswitches offering quantitative isomerization 14 and light-responsive molecular switches in cyclodextrinbased supramolecular systems. 13 Recently, arylazopyrazoles have been widely used as important photoswitches offering quantitative isomerization 14 and light-responsive molecular switches in cyclodextrinbased supramolecular systems.…”

Synthesis and evaluation of orally active small molecule HIV-1 Nef antagonists

“…12,13 The original hit compound, referred to as ‘B9’, consists of a three-ringed structure with a diazene linker connecting a pyrazole core to a chlorophenyl group (compound 1 ; Table 1) 13 . This compound binds directly to recombinant Nef with a K D value in the nanomolar range, and inhibits Nef-dependent enhancement of HIV-1 infectivity and replication in vitro .…”

“…Previous studies have shown that B9 (compound 1 ) inhibits Nef-dependent HIV-1 infectivity in this system and was included as a positive control. 12,13 Analogs with one- and two-carbon linkers (compounds 2 and 4 ) suppressed Nef-mediated enhancement of HIV-1 infectivity with IC 50 values of 0.69 μM and 3.54 μM, respectively (Table 1). These values agree favorably with results from the B9 parent compound, which yielded an IC 50 value of 2.53 μM.…”

“…Previous studies have shown that Nef strongly enhances HIV-1 replication in this cell line 12,13,18-20 , making it a valuable model to study the antiretroviral impact of Nef inhibitors in cell culture. As shown in Figure 3, non-azo analogs 2 and 4 both suppressed Nef-dependent enhancement of HIV-1 replication to the same extent as B9 at 3 μM, while the non-binding analogs lacking the thioamide moiety ( 3 and 5 ) had no activity at this concentration.…”