Wilgerodt-kindler reaction

Significant Variables in a Wilgerodt-Kindler Reaction, Fractional Factorial... 

Acetyl-6-methoxy-naphthalene may be prepared by the acylation of 6-methoxynaphthalene. The resulting product is then subjected to a series of reactions, namely Wilgerodt-Kindler reaction, esterification, alkylation and hydrolysis ultimately yields /)Z-Naproxen. Resolution of the resulting racemic mixture is caused through precipitation of the more potent /)-enantiomer as the cinchonidine salt. 

Methyl-IPs are readily oxidized by elemental sulphur by the Wilgerodt-Kindler reaction. Yutilov and Shcherbina found that compounds 295, 619, 620 and 621 were cleanly oxidized with sulphur in the presence of aromatic amines at 170-180 °C to give IP 2-thiocarbanilides 622-625. At a ratio of 2-methyl-IP-sulphur-amine of 1 5 4, the reaction was complete in 15-20 h, and the yields of the resulting thio-anilides were 60 81%. IbP 623 and 624 were obtained in quantitative yield at an equimolar ratio of the substrate and sulphur and double excess of aniline (96ZOR586, 96JOU564). 

An intramolecular Wilgerodt-Kindler reaction is performed by fusion of IcP 22 with sulphur at 300 °C to form tetracyclic base 626 in low yield. Presumably, this... 

It is interesting to compare the product of the interaction of 2-methyl-IbP 627 and excess thionyl chloride with that from a Wilgerodt-Kindler reaction. Short refluxing of this mixture gave a trisulphane of unusual structure 628 in low yield that at room temperature with diethylamine for a short time resulted in its conversion to 2-carbothioamide 629. The treatment of 2-methyl-IbP 627 with thionyl chloride in dichloromethane and then by amine furnished 2-carbothioamide 629 (89JHC1819). 

The Wilgerodt-Kindler reaction has been discussed recently in connection with its applicability to the synthesis of thioformamides. The simultaneous action of sulphur and excess morpholine on o -thio-keto-acids has been shown to result in substitution of the carboxylic acid group by a morpholino-group, thus yielding thiomorpholides in high yields. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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