Oxidative dual C–H thiolation of imidazopyridines with ethers or alkanes using elemental sulphur

Abstract

Dual C-H thiolation reactions using elemental sulphur remain a challenge. This communication discloses an oxidative radical dual sp/sp C-H thiolation strategy for the coupling of imidazopyridines with ethers or alkanes using elemental sulphur.

Metal‐Free Thiolation of Imidazopyridines with Functionalized Haloalkanes Using Elemental Sulfur

“…Based on our results and previous reports concerning the thiolation using elemental sulfur,–, a possible reaction mechanism has been proposed (Scheme ). At high temperature, imidazopyridine 1a exists as the resonance structure A , which undergoes a nucleophilic reaction with elemental sulfur to give intermediate B [Eq.…”

“…Our group developed the first oxidative radical dual C–H thiolation of imidazopyridines with ethers and alkanes using elemental sulfur; however, the reaction scope was not particularly broad [Scheme , Eq. (3)] . Due to the fact that there are many types of halogenated alkanes bearing functional groups, thiolation of imidazopyridines with such alkanes using elemental sulfur can provide a diverse arrary of interesting thiolated imidazopyridine products.…”

“…Due to the fact that there are many types of halogenated alkanes bearing functional groups, thiolation of imidazopyridines with such alkanes using elemental sulfur can provide a diverse arrary of interesting thiolated imidazopyridine products. In continuation of our research concerning the modification of imidazopyridines,,,, we herein report a metal‐free, three‐component thiolation reaction of imidazopyridines with functionalized alkyl halides using elemental sulfur [Scheme , Eq. (4)].…”

Recent Advances in Radical C−H Bond Functionalization of Imidazoheterocycles

“…In 2017, Tang and his group introduced a DTBPmediated dual oxidative sulfenylation (thiolation) of imidazo[1,2-a]pyridine with ethers or alkanes using elemental sulphur (S 8 ) at 120°C (Scheme 49). [76] A broad range of imidazo [1,2- In 2019, Guo and co-workers developed a DCPmediated alkylselenylation of imidazo[1,2-a]pyridine using Se powder and ethers or alkanes at 130°C for 12 h (Scheme 50). [77] A wide range of ethers/alkanes 13 reacted with substituted imidazo [1,2-a] Wang and co-workers investigated a visible lightinduced, Eosin B-catalyzed sulfenylation of imidazo-[1,2-a]pyridines 1 using arylsulfinic acids 80 in DCE at room temperature (Scheme 51).…”

K2S2O8-Promoted Aryl Thioamides Synthesis from Aryl Aldehydes Using Thiourea as the Sulfur Source

“…The synthesis of sulfur-containing organic compounds has received much attention in recent years, due to their wide applications in biology, chemistry, and materials science [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. There are many sulfur reagents for their synthesis, such as P 2 S 5 [ 11 ], Lawesson’s reagent [ 12 ], disulfides [ 13 , 14 , 15 ], thiols [ 16 , 17 , 18 , 19 ], sulfonyl hydrazides [ 20 , 21 , 22 , 23 ], sodium sulfonate [ 24 , 25 , 26 , 27 , 28 ], and elemental sulfur [ 29 , 30 , 31 , 32 ]. Among them, both P 2 S 5 and Lawesson’s reagent are the most widely used reagents, and yet they have an obvious drawback of being sensitive to moisture.…”