A general synthetic route for 1-substituted 4-oxygenated β-carbolines (Synthetic studies on indoles and related compounds 41)

Catalytic Enolate Arylation with 3-Bromoindoles Allows the Formation of β-Carbolines

Synthesis of substituted β-carbolines was accomplished by utilizing the catalytic enolate arylation reaction of ketones in conjunction with several 3-bromoindole derivatives. Quenching of the arylation reaction in situ with an electrophile allowed ready incorporation of functionality at the carboline C-4 position in an efficient one-pot protocol.

Copper-catalyzed multicomponent coupling/cycloisomerization reaction between substituted 1-formyl-9H-β-carbolines, secondary amines, and substituted alkynes for the synthesis of substituted 3-aminoindolizino[8,7-b]indoles

A copper-catalyzed efficient one step three component strategy for preparing a library of aminoindolizino[8,7-b]indoles from N-substituted 1-formyl-9H-β-carbolines, secondary amines, and substituted alkynes with high atom economy has been developed.

Synthesis and Evaluation of β-Carbolinium Cations as New Antimalarial Agents Based on π-Delocalized Lipophilic Cation (DLC) Hypothesis

Several beta-carbolines including naturally occurring substances and their corresponding cationic derivatives were synthesized and evaluated for antimalarial (antiplasmodial) activity in vitro and in vivo. A tetracyclic carbolinium salt was elucidated for antileishmanial and antitrypanosomal activities in vitro as well as antiplasmodial activity. Quarternary carbolinium cations showed much higher potencies in vitro than electronically neutral beta-carbolines and a good correlation was observed between pi-delocalized lipophilic cationic (DLC) structure and antimalarial efficacy. beta-Carbolinium compounds exhibit medium suppressive activity in vivo against rodent malaria.

π-Delocalized β-carbolinium cations as potential antimalarials

Several beta-carboline compounds including natural products and their corresponding salts were synthesized and evaluated for antimalarial activity and cytotoxicity levels. Quaternary carbolinium cations showed much higher potencies than neutral beta-carbolines and a good correlation was observed between pi-delocalized lipophilic cationic structure and antimalarial efficacy.

A New Furanoid Diterpene from Caesalpinia pulcherrima

A new cassane-type diterpene isovouacapenol E (1) was isolated from the leaves of Caesalpinia pulcherrima, together with the known compounds caesaldekarin A (3), spathulenol (4), caryophyllene oxide (5), phytol, and sitosterol. The structure of 1 was elucidated by spectral data interpretation.

[New reactivities of nitrogen-containing aromatics and their synthetic application]

This review describes new knowledge on reactivities and syntheses of N-containing aromatics and their application to the synthesis of natural products covering three subjects. 1) The first part describes the Fischer indole synthesis of o-substituted phenylhydrazones, its mechanism, Reissert indole synthesis, a new synthetic approach from pyrrole to indole, some reactions of indoles (i.e., etc.), acylation, bromination, debromination, debenzylation, Vilsmeier-Haack reaction, and synthesis of 4-methoxy-beta-carboline alkaloids. 2) The second part describes a new method of introduction of allyl and vinyl groups on the indole nucleus by means of a Pd catalyst. This method was applied to the synthesis of optically active ergot alkaloids. 3) The third part describes the synthesis of o-substituted diacylanilines and its application to chemoselective acylating reagents. A study on axial chirality based on the Ar-N axis is also involved.