Thionation Of Amides Research Articles

Synthesis of 1,2,3-triazole-fused N-heterocycles from N-alkynyl hydroxyisoindolinones and sodium azide via the Huisgen reaction.

An efficient methodology for the synthesis of dihydro[1,2,3]triazolo-pyrimidoisoindolones and dihydro[1,2,3]triazolo-diazepinoisoindolones has been developed using the Huisgen reaction from sodium azide and alkyne substituted amido alcohols in moderate to good yields. The reaction involves the in situ generation of the N-acyliminium ion intermediate, which undergoes a nucleophilic attack by the azide ion, followed by a [3 + 2]-intramolecular azide-alkyne cycloaddition reaction. Importantly, the reaction proceeds without the involvement of any transition metal catalyst. This methodology can be further utilized for the synthesis of dihydro[1,2,3]triazolo-pyrimidoisoindolthiones via thionation of amides.

Thionation Using Fluorous Lawesson′s Reagent.

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Thionation Using Fluorous Lawesson's Reagent

[reaction: see text] Thionation of amides, 1,4-diketones, N-(2-oxoalkyl)amides, N,N'-acylhydrazines, and acyl-protected uridines with the use of a fluorous analogue of the Lawesson's reagent leads to thioamides, thiophenes, 1,3-thiazoles, 1,3,4-thiadiazoles, and acyl-protected 4-thiouridines. The isolation of the final products in high yields is achieved in most cases by a simple filtration (fluorous solid-phase extraction).

Atroposelectivity of Reactions of Benzylic Metalated Thiobenzamides and Thionaphthamides.

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Atroposelectivity of Reactions of Benzylic Metalated Thiobenzamides and Thionaphthamides

AbstractN,N‐Dialkyl‐2‐methylbenzenecarbothioamides and naphthalenecarbothioamides were prepared by thionation of amides with Lawesson’s reagent under unusual conditions. Their axial chirality was evidenced. Benzylic deprotonation of thioamides bearing N,N‐diisopropyl groups with sec‐butyllithium was selective. The resulting anions were reacted with prochiral electrophiles (aromatic aldehydes, an unsaturated aldehyde or ketone, and an imine) to afford diastereomeric adducts (up to 88:12 dr). This is the first report on atroposelective C−C bond formation in the benzylic position of thioamides. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)