Formaldehyde → 5-Benzyloxy-2-[2-(2-methyl-1,2,3,4-tetrahydro-isoquinolin-7-yl)-ethyl]-2H-pyridazin-3-one

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Reaction Steps

To 90 mg (0.25 mmol) 5-benzyloxy-2-[2-(1,2,3,4-tetrahydro-isoquinolin-7-yl)-ethyl]-2H-pyridazin-3-one (example 25.1) in 2.0 mL THF is added 28 μL (0.37 mmol) aqueous 37% formaldehyde solution. The mixture is acidified with 2 drops of acetic acid and then 79 mg (0.37 mmol) sodium triacetoxy-borohydride is added. The reaction mixture is stirred 2 h at RT and is poured into aqueous 10% Na2CO3-solution, the layers are separated and the aqueous phase is extracted with EtOAc. The combined organic phase is washed with water, dried over MgSO4, filtered and the solvent is evaporated. The residue is dissolved in DMF and is purified via reverse HPLC chromatography (Waters symmetry, C18; water (0.15% formic acid)/acetonitrile 95:5 to 5:95).

Provenance & Evidence