Cascade bicyclization of triethylammonium thiolates with hydrazines: efficient access to pyrazolo[3,4-c]quinolines

An efficient cascade synthesis of substituted 6,9-dihydro-1H-pyrazolo[3,4-f]quinoline- 8-carbonitriles

The synthesis of pyrazolo[3,4-f]quinoline-8-carbonitriles 4a–h and 6a–k involves the reaction of an aromatic aldehyde, 1H-indazol-6-amine and 3-(1H-indol-3-yl)-3-oxopropanenitrile or 3-oxo-3-arylpropanenitrile in ethanol under mild conditions.

I2-Catalyzed sulfenylation of indoles and pyrroles using triethylammonium thiolates as sulfenylating agents

Readily available triethylammonium thiolates were proven to be new and eco-friendly sulfenylating agents for the efficient and practical construction of sulfenylated indoles and pyrroles (48 examples) with good to excellent yields under metal-free and microwave irradiation conditions. The combination of I₂ and DMSO enabled direct C-S bond formation, allowing easy and low-cost access to new functionalized C,S-tethered bisindoles and pyrrole-indole pairs with a wide diversity of substituents. The mechanism involving S-S and S-I bond-forming/breaking events was proposed.