Bromoarylation of Methyl 2-Chloroacrylate under Meerwein Conditions for the Synthesis of Substituted 3-Hydroxythiophenes

Abstract

Methyl 3-aryl-2-bromo-2-chloropropanoates can be prepared by Meerwein reaction from methyl 2-chloroacrylate and various arenediazonium salts under copper(II) bromide catalysis. The resulting readily available compounds were used as starting materials in reactions with substituted methanethiols for the construction of substituted 3-hydroxythiophenes which have not yet been accessible by other routes. Structural variety of the obtained 2-substituted 5-aryl-3-hydroxythiophenes has been achieved due to a wide range of available starting materials, including both anilines and thiols.

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

“…26 Although aryldiazonium salts have been used previously to prepare α-functionalized thiocyanates, 27 syntheses of α-thiocyanato ketones by Meerwein reactions seemingly have not been described to date. In continuation of our studies (Meerwein reactions, 28,29 aminothiazoles, 4 pyrazole derivatives 30 ), we report here on preparations of 4-aryl-3thiocyanatobutan-2-ones, N-pyrazolyl-2-aminothiazole derivatives, and hitherto undescribed heterocyclic ring systems. Thus, first representatives of pyrazolo [4,3-e]thiazolo[3,2-a]pyrimidines are described.…”