Practical synthesis of two novel series of 1,3-disubstituted β-carboline derivatives

Chromatography-Free Multicomponent Synthesis of Thioureas Enabled by Aqueous Solution of Elemental Sulfur

The development of a new three-component chromatography-free reaction of isocyanides, amines and elemental sulfur allowed us the straightforward synthesis of thioureas in water. Considering a large pool of organic and inorganic bases, we first optimized the preparation of aqueous polysulfide solution from elemental sulfur. Using polysulfide solution, we were able to omit the otherwise mandatory chromatography, and to isolate the crystalline products directly from the reaction mixture by a simple filtration, retaining the sulfur in the solution phase. A wide range of thioureas synthesized in this way confirmed the reasonable substrate and functional group tolerance of our protocol.

First total synthesis of β-carboline alkaloid trigonostemine G and its derivatives

The β-carboline core is the base structure of several biologically active natural and unnatural compounds. Herein, we report the first total synthesis of trigonostemine G, which is a newly isolated natural β-carboline alkaloid from the twigs of Trigonostemon filipes. Synthesis of two structurally close derivatives of trigonostemine G is also reported. Key step of the syntheses involves a nucleophilic addition of 5-{[tert-butyl(dimethyl) silyl]oxy}-1H-indole to 1-formyl-β-carboline building blocks.

Access to 2-substituted 1-pyridin-3-yl-β-carboline derivatives by intramolecular radical cyclization-ring opening-SNAr substitution

A new method for the synthesis of 1-pyridin-3-yl-β-carboline derivatives involving an intramolecular radical reaction and S_NAr substitution, is described.