STUDIES ON BERBERINE DERIVATIVES(Ⅰ)PREPARATION OF TETRAHYDROPALMATINE AND ITS METHYL RHODANATE

In order to find an effective hypotensive agent, the authors prepared tetrahydropalmatine from Berberine, which has been obtained from Chinese drugs, "Huang-Lien" (Coptis Teeta Wall.) For the purpose of securing a more effective preparation, its methyl rhodanate, m. p. 208--210°, was prepared by the cleavage of methylene-dioxy, linkage in the isoquinoline nucleus Spath, Mosettig: Ber. 59, 1496 (1926) and subsequent methylation by means of diazomethane. The pharmacological examinations are in progress. The following derivatives have been prepared: 1. Desmethylenedioxy-tetrahydroberberine, m. p. 201--203°. 2. Tetrahydropalmatine C₂₁H₂₅O₄N m.p. 145--146°. 3. Desmethylenedioxy-tetrahydroberberine, acetate C₂₃H₂₅O₆N HI, m. p. 238°. 4. Tetrahydropalmatine methyl rhodanate C₂₃H₂₈O₄ N₂ S, m. p. 208--210°. (Probably belongs to α-type.)