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A Facile Synthesis of [1]Benzopyrano[4,3-b]pyridin-5-ones

✍ Scribed by Ivano, Ivo C. ;Karagiosov, Stoyan K. ;Simeonov, Mario F.

Publisher
John Wiley and Sons
Year
1992
Tongue
English
Weight
455 KB
Volume
1992
Category
Article
ISSN
0947-3440

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✦ Synopsis

Abstract

The title compounds 5a‐c and 7a‐m have been prepared by Vilsmeier formylation of 4‐aminocoumarins 1 yielding aldehydes 2, and subsequent condensation of 2 with C‐H acids in the presence of piperidine. This condensation probably proceeds via the intermediate ylidenemalonic esters 4. By means of detailed ^1^H‐ and ^13^C‐NMR studies a Dimroth‐type rearrangement of intermediates 6f‐m has been found to take place in the course of the formation of products 7f‐m.

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A Facile One-Pot Synthesis of Functional
A Facile One-Pot Synthesis of Functionalized 1,5-Dihydro-2H-[1]benzopyrano[2,3-b]pyridin-5-ones
✍ Abbas Ali Esmaeili; Omid Ghareghani 📂 Article 📅 2007 🏛 John Wiley and Sons 🌐 German ⚖ 77 KB 👁 1 views

## Abstract The highly reactive 1 : 1 intermediate generated in the reaction between dialkyl acetylenedicarboxylate (=but‐2‐ynedioic acid dialkyl ester) **4** and triphenylphosphine was trapped by 2‐amino‐4‐oxo‐4__H__‐1‐benzopyran‐3‐carboxaldehydes **5** to yield highly functionalized dialkyl‐1,5‐d