5-Iodo-2-(trifluoromethyl)pyridine → 3,4-Bis(benzyloxy)-6-{[6-(trifluoromethyl)pyridin-3-yl]ethynyl}pyridazine

Participants

Reaction Conditions

Reaction Steps

A microwave vial was charged with 5-iodo-2-(trifluoromethyl)pyridine (617 mg, 2.260 mmol), copper(I) iodide (39.1 mg, 0.205 mmol), bis(triphenylphosphine)palladium(II) chloride (72.1 mg, 0.103 mmol), 1,8-diazabicycloundec-7-ene (DBU; 1858 μl, 12.33 mmol) and tetrahydrofuran (6849 μl). The reaction mixture was then purged and evacuated with nitrogen and to this was then added 3,4-bis(benzyloxy)-6-ethynylpyridazine (Intermediate 5: 650 mg, 2.1 mmol). The reaction was heated to 80° C. whilst being subjected to microwave radiation for 1 hour. Upon cooling the reaction mixture was partitioned between ethyl acetate and water, at which point a solid formed which was filtered and discarded. The organics were then washed with water and brine, dried (MgSO4), filtered and concentrated to afford a brown oil. This was purified by silica chromatography (eluting with 0-100% ethyl acetate in petrol) to yield 3,4-bis(benzyloxy)-6-{[6-(trifluoromethyl)pyridin-3-yl]ethynyl}pyridazine as a yellow amorphous solid (yield=10%)

Provenance & Evidence