Topic
Benzopyran
About: Benzopyran is a research topic. Over the lifetime, 1889 publications have been published within this topic receiving 15235 citations.
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TL;DR: The procedure affords various benzopyran derivatives where the regioselectivity depends on the structure of both substrates (reaction mechanism) and the reaction mechanism as discussed by the authors.
Abstract: The procedure affords various benzopyran derivatives where the regioselectivity depends on the structure of both substrates (reaction mechanism).
TL;DR: Condensation of 8.formyl, 7.methoxy, 2.7methoxyl, 3.3methioxyl, 4.5methoxide, and 3.1methylbenzopyran-4.4.1.
Abstract: Condensation of 8‐formyl‐7‐methoxy‐2‐phenyl‐4H‐1‐benzopyran‐4‐ones (5a–f) with ethyl‐3‐aminocrotonate (6) in glacial acetic acid under Hantzsch conditions afforded 7‐methoxy‐2‐aryl‐3‐phenyl/or‐H‐8‐[2‐(4,6‐dimethyl‐3,5‐dicarbethoxy‐pyridyl)]‐4H‐1‐benzopyran‐4‐ones (7a–f) in good yields.
TL;DR: The pyran ring cleaved product (3) and the tetracyclic chromene (5) were obtained by using a strong electron withdrawing group at C(6) in the benzopyran, and a conformationally mobile lactam ring as discussed by the authors.
Abstract: The title reactions furnished the pyran ring cleaved product (3) and the tetracyclic chromene (5), rather than the expected 4-cyclicamido-3-hydroxy benzopyrans (1,RCN and NO 2 , respectively, n=11). Mechanisms proposed for these reactions require a strong electron withdrawing group at C(6) in the benzopyran, and a conformationally mobile lactam ring.