Bogdal, Dariusz et al. published their research in Journal of Chemical Research, Synopses in 1998 | CAS: 51473-74-6

7-(Diethylamino)-2-oxo-2H-chromene-3-carbonitrile (cas: 51473-74-6) belongs to nitriles. Trimerization of aromatic nitriles requires harsh reaction conditions, high temperatures, long reaction times, and pressure. Industrially, the main methods for producing nitriles are ammoxidation and hydrocyanation. Both routes are green in the sense that they do not generate stoichiometric amounts of salts.Quality Control of 7-(Diethylamino)-2-oxo-2H-chromene-3-carbonitrile

Coumarins: Fast Synthesis by Knoevenagel Condensation under Microwave Irradiation was written by Bogdal, Dariusz. And the article was included in Journal of Chemical Research, Synopses in 1998.Quality Control of 7-(Diethylamino)-2-oxo-2H-chromene-3-carbonitrile This article mentions the following:

Condensation of salicylaldehyde or its derivatives with various derivatives of Et acetate in the presence of piperidine led to the synthesis of coumarins by a solvent free reaction under microwave irradiation For example, microwave irradiation of salicylaldehyde with di-Et malonate in the presence of piperidine gave 89% 3-ethoxycarbonylcoumarin. In the experiment, the researchers used many compounds, for example, 7-(Diethylamino)-2-oxo-2H-chromene-3-carbonitrile (cas: 51473-74-6Quality Control of 7-(Diethylamino)-2-oxo-2H-chromene-3-carbonitrile).

7-(Diethylamino)-2-oxo-2H-chromene-3-carbonitrile (cas: 51473-74-6) belongs to nitriles. Trimerization of aromatic nitriles requires harsh reaction conditions, high temperatures, long reaction times, and pressure. Industrially, the main methods for producing nitriles are ammoxidation and hydrocyanation. Both routes are green in the sense that they do not generate stoichiometric amounts of salts.Quality Control of 7-(Diethylamino)-2-oxo-2H-chromene-3-carbonitrile

Referemce:
Nitrile – Wikipedia,
Nitriles – Chemistry LibreTexts