1: 6-chloro-nicotinic acid With tritylchloride-polystyrene resin; N-ethyl-N,N-diisopropylamine in dichloromethane; N,N-dimethyl-formamide T=20°C; 18 h; 2: dihydroxy-thien-2-ylborane With potassium phosphate; phenyl-phospha-adamantane; tris(dibenzylideneacetone)dipalladium(0) chloroform complex in tetrahydrofuran; water T=20°C; solid-phase Suzuki coupling; 15 h; 3: With trifluoroacetic acid in dichloromethane T=20°C; 1.5 h; Further stages.;

1: sodium carbonate / tetrakis(triphenylphosphine) palladium(0) / toluene; ethanol / 2 h / 80 °C / Inert atmosphere 2: water; lithium hydroxide hydrate / tetrahydrofuran / 16 h View Scheme