Synthesis of 18-Hydroxyvincamines and Epoxy-1,14-secovincamines; a New Proof for the Aspidospermane-Eburnane Rearrangement

Simple indole alkaloids and those with a nonrearranged monoterpenoid unit

“…Hydroboration-oxidation of 465 produced 17,18-dehydrovincamone (466) (Scheme 91). 164 The first total synthesis of racemic subincanadine F (467), isolated from the bark of the Brazilian medicinal plant Aspidosperma subincanum Mart., was performed from N a -(pmethoxybenzyl)tryptamine in six steps. The key steps were a SmI 2 -mediated ring opening of 468, followed by an acidmediated Mannich reaction in 469 (Scheme 92).…”

A sequential cycloaddition strategy for the synthesis of Alsmaphorazine B traces a path through a family of Alstonia alkaloids

“…[50] An extensive survey of peroxide, peracid, and other oxidants led to complex mixtures of products, apparently triggered by oxidation of the electron-rich tertiary hydroxylamine. A second concern involved the potential sensitivity of the desired product 2 to further oxidation.…”

Synthesis and characterization of amino acid-modified adsorption resins and their adsorption properties in the purification of tabersonine from Voacanga africana seeds

“…Many researchers have reported that tabersonine plays a signicant role in lowering blood pressure and it can be used to semi-synthesize the cerebrally active eburnamine derivatives such as vincamine and the anticancer drug vinpocetine. [9][10][11] In 1973, Poisson published a patent related to acquisition of tabersonine by repeated extraction and crystallization. 8 However, this method has many disadvantages, such as the use of toxic extraction solvents and the low yield of tabersonine.…”