2021年10月14日 · 2H-pyran | C5H6O | CID 186148 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety/hazards/toxicity information, supplier lists, and more.

In chemistry, pyran is a six-membered heterocyclic, non- aromatic ring, consisting of five carbon atoms and one oxygen atom and containing two double bonds. The molecular formula is C 5 H 6 O. There are two isomers of pyran that differ by the location of the double bonds.

吡喃，是含有一个氧原子的完全不饱和六元杂环化合物，它有两个双键，根据双键位置的不同，可以有两个异构体：2H-吡喃和4H-吡喃。 吡喃并不是一个闭合的共轭体系，但它的吡啶季铵盐的类似物吡喃鎓盐是一个闭合的共轭体系，有一定的芳香性和稳定性。 未取代的吡喃在自然界尚未发现，其自身价值也不大，但吡喃的衍生物，尤其是吡喃酮，则广泛存在于许多天然自然物质中。 苯并吡喃（色烯）、色酮、香豆素、黄酮、异黄酮、花青素等物质都可看作是吡喃的衍生物。 吡 …

吡喃的饱和衍生物有两种： 二氢吡喃 （dihydropyran）和 四氢吡喃 （tetrahydropyran），注意此两者不同于2 H -吡喃和4 H -吡喃。 四氢吡喃是组成 吡喃糖 的基本结构。 α-吡喃从未制得。 γ-吡喃沸点80℃，不稳定，在空气中迅速变色。 易与强酸成 吡喃盐。 [5] γ-吡喃可由 戊二醛 在 氯化氢 和 二氯甲烷 溶液中环化，再用 N, N -二乙基苯胺 于90℃脱去氯化氢而得。 [5] ^ 毛翰梅; 冀政勤. 有機化學. 五南圖書出版股份有限公司. 2001: 349. ISBN 9789571122762. ^ 吡喃. 术语在线. 全国 …

2019年8月9日 · In this review, we discuss the nature of the different physicochemical factors affecting the valence isomerism between 2H-pyrans (2HPs) and 1-oxatrienes, and we describe the most versatile synthetic methods reported in recent literature to access to 2HPs, with the only exception of 2HPs fused to aromatic rings (i.e., 2H-chromenes), which are ...

2025年2月6日 · 2H-Pyran-2-ones (α-pyrones) are biologically significant due to their diverse pharmacological activities. This review highlights advancements in their synthesis from 2021 to 2025, including modern te...

2009年9月19日 · We have not covered annulated 2H-pyran-2-ones like coumarins, chromones etc. Our intention is to provide an overview of the presence and significance of the 2H-pyran-2-one ring system found in various important natural products and their therapeutic

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By formula: C5H8O+ H2 = C5 H10 O.

2H -Pyran remains to be isolated, but 1 H data for the simple bicyclic derivative 27 have been reported <1999S1209>. Updated spectral data for 4 H -pyran including coupling constants and analysis have been reported <2000JA287>.