Substituent diversity-directed synthesis of indole derivatives

N1-(5-Fluoro-2,4-dinitrophenyl)-N2-phenyl-4-(trifluoromethyl)benzene-1,2-diamine

Treating 1,5-difluoro-2,4-dinitrobenzene (1) with N1-phenyl-5-(trifluoromethyl)benzene-1,2-diamine (4) and N,N-diisopropylethylamine in EtOH at ca. 0 °C for 4 h affords a mixture of N1-(5-ethoxy-2,4-dinitrophenyl)-N2-phenyl-4-(trifluoromethyl)benzene-1,2-diamine (5) (38%) and N1-(5-fluoro-2,4-dinitrophenyl)-N2-phenyl-4-(trifluoromethyl)benzene-1,2-diamine (6) (51%) that can be separated by chromatography. Repeating the reaction in dichloromethane led to the sole formation of N1-(5-fluoro-2,4-dinitrophenyl)-N2-phenyl-4-(trifluoromethyl)benzene-1,2-diamine (6) in 96% yield.

One-pot synthesis of 2-amino-indole-3-carboxamide and analogous

An efficient one-pot, two-step solution-phase synthetic method was developed to synthesize twenty-three 2-amino-indole-3-carboxamides (3) from 2-halonitrobenzene (1) or heterocyclic analogous and cyanoacetamides (2). In this sequence, first, intermediate 2-cyano-2-(2-nitrophenyl)acetamide (4) was generated under basic condition via S(NAr) reaction; after direct addition of hydrochloric acid solution, FeCl(3), and Zn powder, indole 3 was generated via reduction/cyclization process.