Dimethylformamide → 2-Bromo-5-hydroxy-N-[2-(4-hydroxyphenyl)ethyl]-4-methoxy-N-methylbenzamide

Participants

Reaction Conditions

Reaction Steps

To a solution of 138 g 2-bromo-5-hydroxy-4-methoxy benzoic acid (B13) in MIBK (690 mL) was added thionyl chloride (106 g) and DMF (13 mL) and the reaction mixture was heated to 80° C. and stirred at this temperature until TLC analysis indicated the complete disappearance of B13. The resulting mixture was subjected to distillation to remove the excess thionyl chloride. After distillation of thionyl chloride, the resulting acid chloride solution was cooled to room temperature and was added to a solution of 100 g of N-methyl-N-(2-[4-hydroxyphenyl]ethyl) amine HBr (A12 HBr) and 94 g Na2CO3 in 1000 mL of MIBK and 600 mL H2O pre-cooled to 0° C. A solution of NaOH (82.5 g) in 165 mL H2O was added slowly to maintain the temperature under 5° C. The reaction mixture was stirred at this temperature until TLC analysis showed the complete disappearance of B13 acid chloride. The pH of the reaction mixture was brought to 10-11 by adding more NaOH and the resulting mixture was heated to 50° C. and stirred at this temperature for another 1 h. The reaction mixture was cooled to room temperature and the aqueous layer was separated. The organic layer was concentrated to ⅕th of its volume. 500 mL of heptane was added. The precipitate was collected by filtration to give 163 g (65% yield) of N-methyl-N-(2-[4-hydroxyphenyl]ethyl)-2-bromo-5-hydroxy-4-methoxy benzene carboxamide (C2).

Provenance & Evidence