2,5-Dibromofuran

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

Procedure: Pd(Ph3P)4 (580 mg, 3%), CuI (140 mg, 2%) and propargyl alcohol (4.65 ml, 67.7 mmol) are added successively to a solution of 2,5-dibromofuran (5.1 g, 22.6 mmol) in n-propylamine (100 ml), and the mixture is stirred at RT for 1 h and then under reflux for 24 h. More propargyl alcohol (2.0 ml, 33 mmol) is then added and the mixture is stirred under reflux for another 8 h. After cooling, the reaction mixture is filtered off with suction through kieselguhr and washed with ethyl acetate (50 ml). The organic phase is concentrated under reduced pressure. Further purification is carried out by chromatography [Tol/Ac (8:2)] over a silica gel column. This gives the title compound (3.8 g) as a colorless solid. TLC, silica gel (glass plates), [toluene/acetone (8:2)], Rf=0.40. under reflux for 24 h the mixture is stirred under reflux for another 8 h After cooling the reaction mixture is filtered off with suction through kieselguhr washed with ethyl acetate (50 ml) The organic phase is concentrated under reduced pressure Further purification

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

Procedure: Pd(Ph3P)4 (580 mg, 3%), CuI (140 mg, 2%) and propargyl alcohol (4.65 ml, 67.7 mmol) are added successively to a solution of 2,5-dibromofuran (5.1 g, 22.6 mmol) in n-propylamine (100 ml), and the mixture is stirred at RT for 1 h and then under reflux for 24 h. More propargyl alcohol (2.0 ml, 33 mmol) is then added and the mixture is stirred under reflux for another 8 h. After cooling, the reaction mixture is filtered off with suction through kieselguhr and washed with ethyl acetate (50 ml). The organic phase is concentrated under reduced pressure. Further purification is carried out by chromatography [Tol/Ac (8:2)] over a silica gel column. This gives the title compound (3.8 g) as a colorless solid. TLC, silica gel (glass plates), [toluene/acetone (8:2)], Rf=0.40. under reflux for 24 h the mixture is stirred under reflux for another 8 h After cooling the reaction mixture is filtered off with suction through kieselguhr washed with ethyl acetate (50 ml) The organic phase is concentrated under reduced pressure Further purification

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

Procedure: To a cooled (−78° C.) solution of 2,5-dibromofurane (3.06 g, 8.88 mmol) in anhydrous diethyl ether (50 ml) was added n-Butyllithium (3.9 ml of 2.5M solution in Hexanes, 9.77 mmol). The mixture was stirred at this temperature for 90 minutes before the addition of 2-chloropyrimidine. The mixture was stirred for a further 30 minutes before being warmed to room temperature and stirred for further 2 hours. DDQ (2 g, 8.88 mmol) was them added to the solution which was stirred for 30 minutes before being concentrated in vacuo to give a thick brown syrup. The syrup was dissolved in EtOAc and washed with saturated sodium carbonated solution. The organic extract was removed, dried (MgSO4), filtered and concentrated in vacuo to give a crude residue which was purified by flash chromatography (SiO2) (100% hexane going to 7:2—hexane:EtOAc) to give the title compound (3.06 g, 40.20%) in pure form. m/z (LC-MSW, ESP):346 [M+H]+, R/T=4.41 mins stirred for further 2 hours added to the solution which was stirred for 30 minutes before being concentrated in vacuo to give a thick brown syrup washed with saturated sodium carbonated solution The organic extract was removed dried (MgSO4) filtered concentrated in vacuo to give a crude residue which was purified by flash chromatography (SiO2) (100% hexane going to 7:2—hexane:EtOAc)

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

Procedure: In a 2-neck flask was placed 2,5-dibromofuran (18.1 g, 80 mmol) with catalyst Pd(PPh3)4 (5 mol %) and added 30 mL of benzene and 6 mL of 2 M Na2CO3 aqueous solution. The mixture was added 2.2 g (20 mmol) of dihydroxy-2-(furyl) borane dissolved in 6 mL of methanol and heated at reflux for 12 hrs. Thin layer chromatography ("TLC") showed 2 fluorescent spots. The less polar spot was identified as the desired dimer product. The mixture was extracted with ether. The combined ether extracts were dried with anhydrous MgSO4 and concentrated. The crude product was then used for the next reaction. In a 2-neck flask was placed heated at reflux for 12 hrs The mixture was extracted with ether The combined ether extracts were dried with anhydrous MgSO4 concentrated The crude product was then used for the next reaction

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

Procedure: Pd(Ph3P)4 (580 mg, 3%), CuI (140 mg, 2%) and propargyl alcohol (4.65 ml, 67.7 mmol) are added successively to a solution of 2,5-dibromofuran (5.1 g, 22.6 mmol) in n-propylamine (100 ml), and the mixture is stirred at RT for 1 h and then under reflux for 24 h. More propargyl alcohol (2.0 ml, 33 mmol) is then added and the mixture is stirred under reflux for another 8 h. After cooling, the reaction mixture is filtered off with suction through kieselguhr and washed with ethyl acetate (50 ml). The organic phase is concentrated under reduced pressure. Further purification is carried out by chromatography [Tol/Ac (8:2)] over a silica gel column. This gives the title compound (3.8 g) as a colorless solid. TLC, silica gel (glass plates), [toluene/acetone (8:2)], Rf=0.40. under reflux for 24 h the mixture is stirred under reflux for another 8 h After cooling the reaction mixture is filtered off with suction through kieselguhr washed with ethyl acetate (50 ml) The organic phase is concentrated under reduced pressure Further purification