A CaO catalyzed facile one-pot synthesis of 2-aminothiophenes using Gewald reaction was written by Durgareddy, G. A. N. K.;Ravikumar, R.;Ravi, S.;Adapa, Srinivas R.. And the article was included in Pharma Chemica in 2013.Formula: C8H8N2S This article mentions the following:
A series of 2-aminothiophene derivatives I [R1 = H, Me, Ph, etc.; R2 = H, Me, COOEt, etc.; X = COOEt, CN] was synthesized via heterogeneous CaO catalyzed Gewald reaction of an active nitrile or Et ester with ketones in presence of elemental sulfur in ethanol. The present protocol offers several advantages such as low cost material CaO as a catalyst with good yields, shorter reaction time, simple exptl. procedures and low catalyst loading. In the experiment, the researchers used many compounds, for example, 2-Amino-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile (cas: 70291-62-2Formula: C8H8N2S).
2-Amino-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile (cas: 70291-62-2) belongs to nitriles. Nitrile compounds can be prepared by the incorporation of a cyanide source through C–C bond formation or by dehydration of primary carboxamides. Nitriles are susceptible to hydrogenation over diverse metal catalysts. The reaction can afford either the primary amine (RCH2NH2) or the tertiary amine ((RCH2)3N), depending on conditions.Formula: C8H8N2S
Referemce:
Nitrile – Wikipedia,
Nitriles – Chemistry LibreTexts