ChemInform Abstract: ALLGEMEINE METHODE ZUR SYNTHESE VON TELLUROPHENVERBINDUNGEN

Abstract

Nach einem für kondensierte Thiophene und Selenophene bereits bekannten Verfahren werden durch Kondensation eines β‐chlorierten Vinylaldehyds mit Dinatriumtellurid und Umsetzung mit Organohalogenverbindungen sowie nachfolgender basenkatalysierter Carboxycyclisation des nicht isolierten o‐substituierten Aldehydderivats Tellurophenverbindungen mit 25‐30% Ausbeute dargestellt.

The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

“…Reaction of α-haloketones with inorganic sulfide salts give diketosulfides 89 in 50-80% yields ( Scheme 24 ). The latter could be reacted with glyoxal to give thiophene derivatives 90 [ 182 , 183 , 184 , 185 , 186 , 187 ].…”

3-Substituted 4-Bromo-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-1-yloxyl Radicals as Versatile Synthons for Synthesis of New Paramagnetic Heterocycles

“…This dual behavior of these compounds offers an excellent possibility for the synthesis of heterocyclic rings fused to the dihydropyrrole nitroxide ring, such as the Fiesselmann thiophene synthesis. [23][24][25] Compound 5b was reacted with thioglycolic acid methyl ester in acetonitrile in the presence of equimolar DBU to give 2-(methoxycarbonyl)-4,4,6,6-tetramethyl-4,6-dihydro-5H-thieno[2,3-c]pyrrol-5-yloxyl radical (14a) the dihydrothiophene analog of which was synthesized earlier, 26 however its aromatization failed in our hands. Compound 14a was hydrolyzed to carboxylic acid 14b which could be decarboxylated when heated in quinoline with Cu powder.…”

Synthesis of new substituted thieno[2,3-d]imidazolone from hydantoin

“…Tan and Chen 10 have recently described compound 3 as an oil. From derivative 3, using a method developed earlier in our laboratory, 6 we prepared some new thieno [2,3-d]imidazolones. Condensation of 3 with sodium sulfide nonahydrate in DMF or ethanol followed by the addition of an activated halide and cyclisation with a base, afforded derivatives 4a-d (Scheme 4, Table 2 The thieno [2,3-d]imidazolone 4e bearing a methyl ester group was prepared by direct condensation of methyl thioglycolate (Scheme 5) and delivered 5e in a yield very similar to that one using sodium sulfide and ethyl bromoacetate.…”

“…We were interested in finding a novel pathway to synthesize thieno [2,3-d]imidazolones 4 bearing a functional group on the thiophene ring for further transformation. A method developed earlier in our laboratory 6 allows the preparation of functionalized thiophenes starting from the β-chloroacrolein moiety. Application of this method to a N-protected hydantoin was used to get access to thieno [2,3-d] …”