Thiocyanatoarylation of Methyl Vinyl Ketone under Meerwein Conditions for the Synthesis of 2-Aminothiazole-Based Heterocyclic Systems

Abstract

4-Aryl-3-thiocyanatobutan-2-ones were prepared by Meerwein reactions from methyl vinyl ketone and aryldiazonium salts under copper(II) catalysis in 35−75% yields. α-Thiocyanato ketones regioselectively react with 1-methyl-3-aminopyrazole forming N-(3pyrazolyl)-substituted 2-aminothiazoles in 80−91% yields. An ester group in position 3 of the pyrazole induced a regioselective ring-closure reaction followed by an intramolecular cyclization, which gave first representatives of a new heterocyclic system, pyrazolo[4,3-e]thiazolo-[3,2-a]pyrimidine, in 74−93% yields. In addition, the preparations of 5benzyl-4-methylthiazol-2-ones in 84−93% yields are described.

Bioenergetic characteristics of the murine Nemeth-Kellner lymphoma cells exposed to thiazole derivative in complex with polymeric nanoparticles

“…Investigated compounds. The thiazole deriva tive BF1 (N(5benzyl1,3thiazol2yl)3,5dime thyl1benzofuran2carboxamide) was synthesized at the Department of Organic Chemistry of Ivan Franko National University of Lviv and used for preparing of initial 10 mM solution of BF1 in dime thyl sulfoxide [15,18]. The PEGPN Th1 (full name: poly(VEPcoGMA)graft-mPEG k = 1.4% mol, l = 98.6% mol, M n = 240 kDa) was synthesized at the Department of Organic Chemistry of the Lviv Polytechnic National University, as described earlier [21,22].…”

Pyrazolyldiazonium Salts in the Synthesis of 4‐Amino‐1,3’‐bipyrazoles

“…5‐(Chloromethyl)‐1‐phenyl‐1H‐tetrazole 5 d was prepared as described in the literature [44] . The ethyl 3‐amino‐1‐R‐1 H ‐pyrazole‐4‐carboxylates 1 b , d were prepared as we had described previously [37a] . 1‐Propyl‐3‐aminopyrazole 1 c was prepared by a modified procedure [45] .…”

NBS-Promoted Synthesis of Thiocyanated Aminomaleimides and Site-Selective Intramolecular Cyclization Access to 1,4-Benzothiazepines via S–CN Bond Cleavage

“…Various progress such as NBS, oxidants, visible light, electricity, and ultrasound have been employed to promote thiocyanation of different enaminones, leading to thiocyanated enaminones and S/N-heterocycles. However, most of the above methods remained in the thiocyanation stage or further annulation of thiocyanated enaminones based on the nucleophilic site (N1) with S–CN for accessing various thiazole products (Scheme b) . Devising new reactions between enaminones and Thiocyanate salt beyond these pathways for the synthesis of different heterocycles (seven-membered) therefore remains challenging.…”