10.1080/00397910801929465
The study presents a convenient approach to the synthesis of dialkyl 5-oxo-1,2-dihydro-5H-chromeno[4,3-b]pyridine-2,3-dicarboxylates, which are compounds considered privileged scaffolds in synthetic and pharmacological research due to their potential pharmacological activities. The researchers focused on the chemical behavior of enaminocarbaldehydes derived from the coumarin moiety under intramolecular Wittig reaction conditions. Key chemicals used in the study include triphenylphosphine, dimethyl or diethyl acetylenedicarboxylates, and various enaminoaldehydes (1a–g), which are readily available by treating 4-hydroxycoumarin with different amines and then formylated under Vilsmeier-Haack reaction conditions. These chemicals served the purpose of facilitating the synthesis of the target compounds in good to high yields, expanding the scope of synthetic methods for creating biologically active ingredients and fluorescent dyes.
10.1021/jo00805a002
The study investigates the reactions of 2-diazoacenaphthenone (1) with various olefins and acetylenes. The researchers found that 1 did not decompose in boiling benzene or toluene but underwent copper-catalyzed thermolysis in boiling toluene to form biacenedione. In boiling xylene, 1 produced biacenedione and a trace amount of acenaphthenequinone ketazine. When 1 reacted with olefins like ethyl acrylate, acrylonitrile, ethyl a-bromoacrylate, and methyl vinyl ketone in refluxing benzene, it yielded spiro[acenaphthenone-2,1'-cyclopropanes] (3a-d, 4a-c, 7) with two stereoisomers for some reactions. Reactions with acrolein, phenylacetylene, and diethyl acetylenedicarboxylate led to the formation of 2'-hydroxymethylspiro[acenaphthenone-2,1'-cyclopropanes] (5, 6) and spiro[acenaphthenone-2,3'(3'H)-pyrazoles] (9, 10). The study also explored the reaction of 1 with bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, producing spiro[acenaphthenone-2,3'-tricyclooctanedicarboxylic anhydride] (8). The researchers used various analytical techniques to confirm the structures and properties of the synthesized compounds.
C
