Recognition of the dihydroxybenzamide as the active scaffold of HIV 1 IN inhibitors As depicted in Table 1, the alkyloxy substituted salicylic acid derivatives typically displayed weak inhibition against order CX-4945 IN regardless of the substituent structure and position. Even the incorporation of the chelation advancing hydroxylamino group in to the alkyloxy salicylic acid scaffold just somewhat enhanced the binding, while hydroxamic acids were reported to facilitate the binding of two Mg2 ions by the azaindolebased IN inhibitors,18 which implied the ineffectiveness of the alkyloxy substituted salicylic acid scaffold as IN inhibitor. But, the developed dihydroxybenzamide exhibited average inhibition against strand transfer reaction. The D dihydroxybenzamide 5a showed IC50 values of 35uM and 100uM in strand transfer and suppressing Meristem 3 processing, respectively. The elimination of the phenolic hydroxy at the 3 position by conversion to a benzyl ether paid down the inhibitory efficiency by fold relative to the 3 hydroxy analog 5a, which might derive from the reduction of the metal binding region. Moreover, the dihydroxybenzamide derivatives weren’t cytotoxic in cells at the concentration of up to 40 uM. Subsequently, the dihydroxybenzamide was chosen because the design for further structural modification to improve potency. The SAR study on the dihydroxybenzamide situated IN inhibitors included structural variation on the left side catechol group and the correct side benzamide moiety. The alternative on the phenyl reversible HSP90 inhibitor ring of the core was investigated, and the structural variation on the best side carboxamide group was substituted phenyl ring separately and explored with heterocycle. The activity data is summarized in Table 2 and rationalized by molecular modeling. SAR research with regard to the structural variation on the portion and phenyl ring of the dihydroxybenzamide scaffold We prepared compounds with modification on the right side of the core structure. Whereby the amine and the amide collectively caused a growth in the 3 handling inhibitory activity in comparison with the parent compound 5a, a range of aryl or alkyl replaced amines were researched. The lipophilic substituent such as naphthalenyl and difluorophenyl groups were very theraputic for the strand transfer inhibition. In particular, the thiophenyl, furanyl and phenyl alterations markedly improved the potency of strand transfer inhibition. Nevertheless the result of the replacement varied in line with the linker length and substituted place, in which the substituent was methyl group. Conversely, the N methyl carbamoyl substitution at the 2 position of the 4 fluorophenyl band triggered a loss of IN inhibitory potency.