Cesium carbonate → HCID 11552467, compound

Participants

Reaction Steps

To a suspension of 0.462 g (0.0004 mol) tetrakis(triphenylphosphine)-palladium(0) in 45 ml dry dimethoxyethane, 5.00 g (0.0136 mol) (R)-5-[1-(4-bromo-phenyl)-ethylcarbamoyl]-thiophene-2-carboxylic acid methyl ester were added and stirred for 10 min at room temperature under nitrogen atmosphere. 3.65 g (0.0285 mol) thiophene-2-boronic acid in 20 ml ethanol and 14.3 ml (0.0286 mol) of a 2 M aqueous solution of Cs2CO3 were added and the mixture was heated to 75-80° C. for 3 hours. After 1.25 hours, another 0.5 equivalents of thiophene-2-boronic acid and Cs2CO3 were added to the mixture. The warm reaction mixture was filtered, the solid was washed with ethyl acetate and the solvent of the filtrates was evaporated. The residue was dissolved in dichloromethane, washed with water, dried over magnesium sulfate and the solvent was removed. The crude product was recrystallized from n-butanol/n-heptane 1:2 and dried in vacuum to give 2.52 g (0.00678 mol) (R)-5-[1-(4-thiophen-2-yl-phenyl)-ethylcarbamoyl]-thiophene-2-carboxylic acid methyl ester.

Provenance & Evidence