Symmetrical Phosphinic\nAcids: Synthesis and Esterification\nOptimization toward Potential HIV Prodrugs

A highly efficient method to synthesize diverse symmetrical\nphosphinic\nacids with the potential to act as pivotal candidates in the design\nof HIV-1 protease inhibitors has been developed. Such compounds have\nbeen designed based on the enzyme–substrate specificity, and\ntheir elongated analogues are expected to demonstrate significant\ninhibition against the HIV-1 protease with IC<sub>50</sub> values\nin the low nanomolar range. Moreover, a highly efficient esterification\nprotocol with carbohydrates and flavonoids has been devised to address\nthe inherent absorption challenges associated with phosphinic-based\ndrugs. These esters not only exhibit low toxicity but also have the\npotential to generate flavonoid moieties in situ, which are associated\nwith hepatoprotective effects, or naturally occurring carbohydrate\nmetabolites. The methodology utilizes effective peptide coupling reagents,\nsuch as aminium-based TBTU and carbodiimide-based DIC, and affords\nthe target products in excellent to quantitative yields. This research\nrepresents a promising avenue for the development of novel HIV-1 protease\ninhibitors with significant therapeutic benefits.