5-bromopent-2-yne

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

Procedure: A mixture of the ethyl-4-ethoxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylate of Example 19c (8.13 g.), pulverized anhydrous potassium carbonate (14.3 g.) and 1-bromo-3-pentyne (10.7 g.) in dry DMF (58 ml.) was stirred at 55°-60° for 4.5 hours. Additional quantities of 1-bromo-3-pentyne (5.3 g.) and potassium carbonate (14.3 g.) were added after 1 hour. The mixture was cooled and filtered and the filtrate evaporated at 45°-50°. The residue was diluted with water and extracted with ether and EtOAc. The combined extracts were washed with water, dried (MgSO4) and evaporated. The residue was purified by chromatography on silica gel using EtOAc/hexane 1:1 v/v as eluant to give the title compound, m.p. 93°-95°, after recrystallization from toluene. The mixture was cooled filtered the filtrate evaporated at 45°-50° The residue was diluted with water extracted with ether and EtOAc The combined extracts were washed with water dried (MgSO4) evaporated The residue was purified by chromatography on silica gel