74597-91-4

Upstream product

• 623-73-4 diazoacetic acid ethyl ester 
• 218941-38-9 3-(bis(benzylthio)methylene) pentane-2,4-dione 
• 123-54-6 acetylacetone 
• 100-44-7 benzyl chloride 
• 74597-98-1 ethyl 4-acetyl-5-mercapto-3-methylthiophen-2-carboxylate 

Relevant academic research and scientific papers

Copper-Catalyzed Annulative Coupling of S,S-Disubstituted Enones with Diazo Compounds to Access Highly Functionalized Thiophene Derivatives

An efficient protocol toward fully substituted thiophenes and thieno[2,3-b]thiophenes has been developed through CuCl2-catalyzed annulative coupling of S,S-disubstituted enones with diazo compounds under mild conditions. Tetrasubstituted thiophenes and thieno[2,3-b]thiophenes were efficiently accessed by variation of the feed ratio of the reactants in good to excellent yields, respectively. The synthetic methodology has demonstrated the potential for the construction of diverse thiophene derivatives.

Condensed Isothiazoles. Part 5. Thienoisothiazoles and Thienoisothiazoles

2,3-Disubstituted thiophens containing a sulphur function (SH, SMe, or SCN) and a carbonyl group (CHO or Ac) have been prepared and converted into thienoisothiasoles.Methods used to prepare 1,2-benzisothiazoles are often inapplicable in the thiophen series.For example, an (E)-methyl (2-methylthio-3-thienyl) O-p-nitrobenzoylketoxime (6) in hot diethylene glycol or acetic acid gave the corresponding 3-acetamido-2-methylthiothiophen (15); in concentrated sulphuric acid at - 5 deg C, it gave the Beckmann rearranged product (15) and a thienothiazole (19).Similarly, (E)-methyl (3-methylthio-2-thienyl) O-p-nitrobenzoyl ketoxime (42) gave 2-methylthienothiazole with concentrated sulphuric acid, but with acetic acid it gave the thienoisothiazole (43) and 2-acetamido-3-methylthiothiophen.Heating the (E)-2-mercaptothiophen-3-carbaldoxime (27) in an inert solvent gave the corresponding thienoisothiazole (14); the (E)-3-mercaptothiophen-2-carbaldoxime (47) cyclised in hot AcOH-Ac2O, to give the thienoisothiazole (44).Thienoisothiazoles were also prepared by treating a methyl (2-mercapto-3-thienyl) ketone (21) with chloramine and by heating a 2-iminothieno-3,1,4-oxathiazepine (29) in an inert solvent.The products obtained by selective S-alkylation of 3,5-bis(sodiomercapto)isothiazole-4-carbonitrile with ethyl bromoacetate and iodomethane were cyclised, to give 4-aminothienoisothiazole derivatives (34) and (36).