5-bromo-1-benzofuran-2-carboxamide

Conditions: temp:125.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 0.30 g of P(t-Bu)3, 4.5 g of 5-bromobenzofuran-2-carboxamide, 4.9 g of benzylpiperazine and 5.0 g of Na t-OBu are added to a suspension of 0.085 g of Pd(II) acetate in 150 ml of xylene after the latter has been stirred for 15 minutes, and the mixture is warmed at 125° C. for 12-18 hours under the protective gas nitrogen. After cooling, the mixture is added to 500 ml of 2N hydrochloric acid, and the aqueous phase is extracted 3 times with 200 ml of ethyl acetate. The aqueous phase is adjusted to pH 10 using aqueous NaOH (20%) with pH and temperature monitoring (20-25° C.), and the 5-(4-benzyl-1-piperazinyl)benzofuran-2-carboxamide produced as a solid is filtered off and crystallized, for example, from ethanol/water (product weight: 4.0 g/64%/m.p. 277-279°). After cooling the aqueous phase is extracted 3 times with 200 ml of ethyl acetate with pH and temperature monitoring (20-25° C.)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Performance of the reaction with ethyl bromoacetate: 200 g of 5-bromo-2-hydroxybenzaldehyde are dissolved in 2000 ml of NMP with stirring, and 144 g of potassium carbonate and 175 g of ethyl bromoacetate are added. The mixture is stirred at 105° under nitrogen for 15 hours. The resultant orange solution dotted with crystals is cooled to 25°, 135 g of formamide are added, and the mixture is stirred for a further 30 minutes. 557 ml of sodium methoxide (30% in MeOH) are then allowed to run in over the course of 15 minutes without cooling. After 3 hours, a brownish solution dotted with crystals is present. It is poured into 6 litres of demineralized water (10°), and the mixture is stirred for a further 30 minutes. The crystals are filtered off with suction, washed with 1 litre of demineralized water, re-suspended in 4 litres of demineralized water, filtered off with suction and re-washed with 1 litre of demineralized water. The crystals are dried overnight to constant weight under reduced pressure at 60° C. (product weight: 113 g of pale beige crystals; m.p. 210-213°; CAS 35351-21-4). The mixture is stirred at 105° under nitrogen for 15 hours is cooled to 25° the mixture is stirred for a further 30 minutes to run in over the course of 15 minutes without cooling the mixture is stirred for a further 30 minutes The crystals are filtered off with suction washed with 1 litre of demineralized water filtered off with suction re-washed with 1 litre of demineralized water The crystals are dried overnight to constant weight under reduced pressure at 60° C. (product weight: 113 g of pale beige crystals; m.p. 210-213°; CAS 35351-21-4)