Access to Thiazole via Copper-Catalyzed [3+1+1]-Type Condensation Reaction under Redox-Neutral Conditions

Abstract

A new strategy for thiazoles via copper-catalyzed [3+1+1]-type condensation reaction from oximes, anhydrides and potassiumthiocyanate (KSCN) is developed herein. The transformation has good functional group tolerance and various thiazoles were formed smoothly in good to excellent yields under mild reaction conditions. This process involves copper-catalyzed N-O/C-S bond cleavages, activation of vinyl sp C-H bond, and C-S/C-N bond formations which are under redox-neutral conditions as well as operational simplicity.

Visible‐Light‐Promoted Synthesis of Fluoroalkylated Oximes

“…Oximes are useful moieties that can be used as intermediates for synthesizing various organic compounds . In particular, oximes can be converted to various heterocycles including indole, isoquinoline, azirine, pyrrole, pyridine, and thiazole . Herein, we present a new synthetic method to prepare fluoroalkylated oximes, which are potential fluoroalkyl building‐blocks, from amino compounds and fluoroalkylated alkenes [Scheme b].…”

“…[7] In particular,o ximes can be converted to varioush eterocyclesi ncluding indole, [8] isoquinoline, [9] azirine, [10] pyrrole, [11] pyridine, [12] and thiazole. [13] Herein, we present an ew synthetic methodt op repare fluoroalkylated oximes, which are potential fluoroalkyl building-blocks, from amino compoundsa nd fluoroalkylated alkenes [Scheme 1b]. In the process, the addition of an aryl radical, generated from the in situ formed diazonium salt, to a fluoroalkylated alkene [14] is followed by oxime formation, where an itrite is utilized both as ad iazotizing agent and an oxime source.We commencedt he study using aniline 1a and 2-perfluorohexyl ethylene ( 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooct-1-ene, 2a)a sm odel substrates for the synthesis of perfluoro-1-phenyloctan-2-one oxime 3aa (Table 1).…”

Synthesis of new thiazole and thiazolyl derivatives of medicinal significant-a short review

“…24 Copper also, facilitated [3+1+1]-type condensation of oximes, anhydrides and potassiumthiocyanate (KSCN) to give thiazoles in very good yields under very mild reaction conditions. 25,26 The uses of DABCO (1,4-diazabicyclo[2.2.2]octane) as an organocatalyst for synthesis of new thiazole derivatives in short reaction times and good to high yields was also reported. 27 Due to reactivity of 2-amino-4,5,6,7tetrahydrobenzo[b]thiophene-3-carbonitrile towards thioglycolic acid the latter was used with different chemical reagents to give many thiazole derivatives.…”

One‐pot solvent‐free synthesis of novel functionalized ethyl 2‐(alkylimino)‐4‐methyl‐3‐(alkanoyl)‐2,3‐dihydrothiazole‐5‐carboxylates

“…Because of the biological and pharmaceutical importance of thiazole derivatives, several methods for their synthesis have been developed. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] We recently have combined three most attractive conditions, namely one-pot, solvent-free, and noncatalytic, for the synthesis of novel thiazoles. [25][26][27][28][29][30] In continuation to our previous reports on the synthesis of novel sulfur-containing organic compounds, here we describe an efficient, green, and one-pot method involving two consecutive steps for the synthesis of novel functionalized 2,3-dihydrothiazole derivatives under mild, solvent-and catalyst-free conditions (Scheme 1).…”