Convenient synthesis of O-alkylated/N-acylated polyhydroxyazepane based compounds for modulating MD-2-TLR4 complex formation

Abstract

Toll-like receptor 4 (TLR4) is a critical component of the innate immune system, recognizing lipopolysaccharide (LPS) from Gram-negative bacteria and triggering immune responses. The activation of TLR4 involves several key steps, including interactions with LPS-binding protein (LBP), CD14, and myeloid differentiation protein 2 (MD-2), culminating in the formation of the (LPS.MD-2 TLR4)2 complex. Structural insights show that LPS acyl chains insert into the hydrophobic pocket of MD-2, driving TLR4 activation. Inspired by this understanding, numerous natural and synthetic compounds have been developed to inhibit TLR4 by targeting the MD-2/TLR4 complex. Eritoran 1, is one such illustration. The conformational flexibility of azepane architecture inspired us to visualize O-alkylated/N-acylated polyhydroxyazepane-based compounds toward this objective. The docking studies and molecular simulation studies supported the rationale. Synthesis of O-alkylated/N-acylated polyhydroxyazepane-based compounds 2-4 (a-h) through a key building block is described herein.