Synthesis of 5‐oxo‐5H‐chromeno[3,4‐c]pyridine‐1‐carbonitriles and features of their NMR spectra

Abstract

Two different methods leading to 5-oxo-5H-chromeno[3,4-c]pyridine-1carbonitriles were investigated. Reactions of 3-aminocrotonirile with substituted salicylaldehydes provided 5-oxo-5H-chromeno[3,4-c]pyridine-1carbonitriles with the same substituent on positions 2 and 4 of the system. The reaction of 3-aminocrotonirile with variety of substituted 3acetylcoumarins lead to 5-oxo-5H-chromeno[3,4-c]pyridine-1-carbonitriles with different substituents on positions 2 and 4. The structures of the products were confirmed by spectroscopic methods. The presence of nitrile moiety in the structures with fixed geometry caused the highly downfield shift of the aromatic proton at position 10 in 1 H NMR spectrum. The electronic factor of the substituents caused variation of this downfield shift.

l-Proline-Catalyzed Three-Component Reaction of 4-Chloro-3-formylcoumarin, Sodium Sulfide, and α-Halo Ketones: A Direct Approach to Thieno[3,2-c]coumarins

“…In view of the above, and following our interest in coumarin chemistry, 9 52 53 we wish to report a facile and organocatalyzed method for the synthesis of thieno[3,2- c ] coumarins under mild reaction conditions that overcomes the drawbacks of the reported methods and gives coumarin products in satisfactory isolated yields.…”

DMAP-Catalyzed Reaction of Diethyl 1,3-Acetonedicarboxylate with 2-Hydroxybenzylideneindenediones: Facile Synthesis of Fluorenone-Fused Coumarins

“…In view of the importance of coumarin and fluorenone entities and in continuation of our efforts in the synthesis of fused coumarins, 32,33 we report herein the base-catalyzed reaction of diethyl 1,3-acetonedicarboxylate with 2-hydroxybenzylideneindenediones leading to fluorenonefused coumarins.…”