Studies on the Chemical Transformations of 6‐Methylchromone‐3‐carbonitrile under Nucleophilic Conditions

Abstract

The chemical reactivity of 6‐methylchromone‐3‐carbonitrile (1) was studied towards some nucleophilic reagents. Reaction of carbonitrile 1 with malononitrile dimer and N′‐[(4‐methoxyphenyl)methylidene]‐2‐cyanoacetohydrazide (5) gave the unexpected chromeno[4,3‐b]pyridine 2 and benzoxocine‐3‐carbohydrazide 6, respectively. Reaction of carbonitrile 1 with 3‐amino‐1,2,4‐triazole, 2‐aminobenzimidazole, 7‐chloro‐4‐hydrazinoquinoline and 3‐hydrazino‐5,6‐diphenyl‐1,2,4‐triazine proceeds via γ‐pyrone ring opening followed by cycloaddition onto the nitrile function leading to a variety of heterocyclic systems. Structures of the new synthesized products were deduced on the basis of their analytical and spectral data.

Synthesis and antimicrobial evaluation of the novel heteroannulated furo[3′,2′:6,7]chromeno[2,3‐b]pyridines: Part 1

“…[ 20–22 ] The ring‐opening ring closure (RORC) reactions of chromone‐3‐carbonitrile are well known. [ 23–26 ] Khellin‐6‐carbonitrile (4,9‐dimethoxy‐5‐oxo‐5 H ‐furo[3,2‐ g ]chromene‐6‐carbonitrile) [ 27 ] may represent a good precursor for building of novel heterocyclic systems fused furo[3,2‐g]chromenes due to the unique position of carbonitrile functional group in khellin‐6‐carbonitrile which is typically similar to chromone‐3‐carbonitrile. The present work is devoted to study the chemical transformations of 4,9‐dimethoxy‐5‐oxo‐5 H ‐furo[3,2‐ g ]chromene‐6‐carbonitrile ( 1 ) toward a variety of acyclic and cyclic active methylene compounds, bearing CH 2 CO group, hoping to construct a series of novel heteroannulated furo[3′,2′:6,7]chromeno[2,3‐ b ] pyridines and evaluate their antimicrobial activity.…”

Heteroannulated Coumarins and Chromones from Chemical Transformations of 6,8‐Dimethylchromone‐3‐carbonitrile

“…Also, coumarins (2 H ‐chromen‐2‐ones) displayed various biological applications such as antifungal, antibacterial, antioxidant, anticoagulant, antiinflammatory, antiviral, anticancer, antitumor, anti‐diabetic, antitubercular, antiplasmodial, and antimalarial activities, as well as fluorescent sensors . 3‐Substituted chromones bearing electron withdrawing groups at position 3 revealed a diversity of transformations upon treatment with nucleophilic reagents . In continuation to our aforementioned work related to γ‐pyrone ring opening followed by ring closure , the present work aims to study the ring opening ring closure reactions of 6,8‐dimethylchromone‐3‐carbonitrile with some nuclophilic reagents under different reaction conditions.…”

Ring Opening and Recyclization Reactions with Chromone‐3‐carbonitrile

“…Chromones bearing an electron‐withdrawing groups at position 3 revealed a variety of transformations upon treatment with nucleophilic reagents . Chromone‐3‐carbonitriles acquire the ability to undergo a nucleophilic 1,4‐attack followed by additional transformations related to γ‐pyrone ring opening and heterocyclizations at the C‐4 atom or at the cyano group . Herein, we aimed to study the reactivity of chromone‐3‐carbonitrile ( 1 ) toward a variety of nitrogen and carbon nucleophiles.…”