Dequaternization of curare bases with sodium thiophenoxide and ethanolamine.
To prepare (+)-tubocurine and O,O-dimethyl-(+)-tubocurine, the commonly used dequaternization procedures with sodium theophenoxide and ethanolamine were investigated. The quaternary compounds were (+)-tubocurarine chloride and the chloride and iodide salts of O,O-dimethyl-(+)-chondocurarine. The results obtained with ethanolamine indicate that Hofmann elimination is a major pathway and that N-demethylation is minor. The elimination products of O,O-dimethyl-(+)-chondocurarine iodide with ethanolamine were identified as O,O-dimethyltubocurinemethine, O,O-dimethyltubocurineisomethine, and O,O-dimethyltubocurinedimethine. N-Demethylation was the primary reaction with sodium thiophenoxide. Thus, dequaternization of (+)-tubocurarine chloride with sodium thiophenoxide provided (+)-tubocurine which, on diazomethylation, yielded O,O-dimethyl-(+)-tubocurine, identical to the compound obtained by N-demethylation of O,O-dimethyl-(+)-chondocurarine chloride with the same reagent.
D055598:Chemical Phenomena; D002621:Chemistry; D003472:Curare / Q000031:analogs & derivatives*; D003640:Dealkylation; D003978:Diazomethane; D004983:Ethanolamines; D008722:Methods; D013438:Sulfhydryl Compounds; D014403:Tubocurarine
D004983:Ethanolamines; D013438:Sulfhydryl Compounds; D003978:Diazomethane; D003472:Curare; D014403:Tubocurarine