Abstract

Pyrano[3,2-b]pyrans are an important class of heterocyclic compound containing fused 4H-pyrans rings that are a structural constituent of many natural, non-natural, drug candidates, synthetic compounds and plays a significant role in the field of medicinal and pharmaceutical chemistry because of their wide-ranging biological activities. The natural γ-pyrone, 5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one, popularly known as kojic acid have emerged as the most effective substrates for the synthesis of several useful dihydropyrano[3,2-b]pyrans and their corresponding spiro-pyrano[3,2-b]pyran derivatives. Furthermore, the attractiveness of 5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one and its derivatives has drastically increased over the past decades due to their vast applications in medicinal chemistry, food industry, cosmetic products, and chemical industry. Benefited from the diversity and application in various fields of the starting materials, an extensive array of synthetic strategies for the construction of dihydropyrano[3,2-b]pyrans and spiro-pyrano[3,2-b]pyran derivatives has been developed successfully over the last decades. This review will summarize all the synthetic strategies developed for the construction of dihydropyrano[3,2-b]pyran and spiro-pyrano[3,2-b]pyrans using the reactivity of 5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one from 1997 to 2020 and focused on their medicinal application. In order to furnish a complete and understandable overview, this review article is organized based on the nature of the catalyst employed.

摘要

吡喃并[3,2- b ]吡喃是一类重要的杂环化合物，含有稠合的4 H-吡喃环，是许多天然、非天然、候选药物、合成化合物的结构成分，在生物医药领域发挥着重要作用。药物和药物化学，因为它们具有广泛的生物活性。天然 γ-吡喃酮，5-羟基-2-（羟甲基）-4 H-吡喃-4-酮，俗称曲酸，已成为合成几种有用的二氢吡喃的最有效底物[3,2- b ]吡喃及其相应的螺吡喃[3,2- b ]吡喃衍生物。此外，5-羟基-2-（羟甲基）-4 H的吸引力-吡喃-4-酮及其衍生物由于在药物化学、食品工业、化妆品和化学工业中的广泛应用，在过去几十年中急剧增加。受益于起始材料的多样性和在各个领域的应用，已成功开发了一系列用于构建二氢吡喃[3,2- b ]吡喃和螺吡喃[3,2- b ]吡喃衍生物的合成策略在过去的几十年里。本综述将总结利用 5-羟基-2-(羟甲基)-4 H的反应性构建二氢吡喃[3,2- b ]吡喃和螺吡喃[3,2- b ]吡喃的所有合成策略-pyran-4-one 从 1997 年到 2020 年，专注于其药用应用。为了提供完整且易于理解的概述，这篇评论文章是根据所用催化剂的性质组织的。