Lipid A is one of the core structures of bacterial lipopolysaccharides (LPSs), and it is mainly responsible for the strong immunostimulatory activities of LPS through interactions with the Toll‐like receptors and other molecules in the human immune system. To obtain structurally homogeneous and well‐defined lipid As and its derivatives in quantities meaningful for various biological studies and applications, their chemical synthesis has become a focal point. This review has provided a survey of significant progresses made in the synthesis of lipid A, and its derivatives that carry diverse saturated and unsaturated lipids, have the phosphate group at its reducing end replaced with a more stable phosphate or carboxyl group, or lack the reducing end phosphate or both phosphate groups, as well as progresses in the synthesis of LPS analogs and other lipid A conjugates. These synthetic molecules have facilitated the elucidation of the structure–activity relationships of lipid A useful for the design and development of lipid A based therapeutics, such as those utilized to treat sepsis, and other medical applications, for example the use of monophosphoryl lipid A as a carrier molecule for the study of fully synthetic self‐adjuvanting conjugate vaccines. These topics are also briefly covered in the current review.

中文翻译：

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脂质A及其衍生物的合成及生物学评价研究进展

脂质A是细菌脂多糖(LPS)的核心结构之一，主要通过与Toll样受体和人体免疫系统中的其他分子相互作用，发挥LPS的强免疫刺激活性。为了获得对各种生物学研究和应用有意义的数量的结构均质且明确的脂质As及其衍生物，它们的化学合成已成为焦点。本综述对脂质 A 及其衍生物的合成方面取得的重大进展进行了调查，这些衍生物携带多种饱和和不饱和脂质，其还原端的磷酸基团被更稳定的磷酸基或羧基取代，或者缺乏还原端末端磷酸盐或两个磷酸基团，以及 LPS 类似物和其他脂质 A 缀合物的合成进展。这些合成分子有助于阐明脂质 A 的结构-活性关系，可用于设计和开发基于脂质 A 的疗法，例如用于治疗脓毒症的疗法，以及其他医学应用，例如使用单磷酰脂质 A 作为药物用于研究全合成自我辅助结合疫苗的载体分子。当前的评论中也简要介绍了这些主题。