Efficient three-component Gewald reactions under Et3N/H2O conditions was written by Abaee, M. Saeed;Cheraghi, Somayeh. And the article was included in Journal of Sulfur Chemistry in 2014.Safety of 2-Amino-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile This article mentions the following:
In a medium consisting of triethylamine and water, α-methylene ketones undergo room temperature Gewald reactions with elemental sulfur and Et cyanoacetate (or malononitrile) to yield 2-aminothiophene derivatives efficiently within short time periods. Because of the high polarity of the medium, products precipitate in the reaction mixtures spontaneously. This makes isolation of the products easy by simple filtration and avoids cumbersome chromatog. separations Mechanistic studies suggest that the reactions proceed via a Knoevenagel condensation pathway. In the experiment, the researchers used many compounds, for example, 2-Amino-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile (cas: 70291-62-2Safety of 2-Amino-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile).
2-Amino-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile (cas: 70291-62-2) belongs to nitriles. Nitrile carbon shifts are in the range of 115–125 ppm whereas in isonitriles the shifts are around 155–165 ppm. Nitrile groups in organic compounds can undergo a variety of reactions depending on the reactants or conditions. A nitrile group can be hydrolyzed, reduced, or ejected from a molecule as a cyanide ion.Safety of 2-Amino-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile
Referemce:
Nitrile – Wikipedia,
Nitriles – Chemistry LibreTexts