Imidazole → [1-[3-(3-chloro-6-oxo-1(6H)-pyridazinyl)propyl]-4-piperidinyl]methyl 4-amino-5-chloro-2,3-dihydro-7-benzofurancarboxylate

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Reaction Steps

1H-imidazole (2.72 g) was added to a solution of 6-chloro-2-[3-[4-(hydroxymethyl)-1-piperidinyl]propyl]-3(2H)-pyridazinone (2.62 g) in THF (100 ml). NaH (60%, 0.4 g) was added, under nitrogen atmosphere. The mixture was stirred for 10 minutes. 1-[(4-Amino-5-chloro-2,3-dihydro-7-benzofuranyl)carbonyl]-1H-imidazole (2.64 g) was added and the resulting reaction mixture was stirred for 15 minutes at room temperature. The solvent was evaporated. The residue was partitioned between water and DCM. The organic layer was separated, dried, filtered and the solvent was evaporated. The residue was purified by column chromatography over silica gel (eluent: CH2Cl2/hexane/(CH3OH/NH3) 50/45/5). The desired fractions were collected and the solvent was evaporated. The residue was crystallized from DIPE with a drop of ACN. The precipitate was filtered off, washed and dried, yielding 1.88 g (39%) of [1-[3-(3-chloro-6-oxo-1(6H)-pyridazinyl)propyl]-4-piperidinyl]methyl 4-amino-5-chloro-2,3-dihydro-7-benzofurancarboxylate (compound 21, mp: 137° C.) In a similar way, [1-[3-(3-methyl-6-oxo-1(6H)-pyridazinyl)propyl]-4-piperidinyl]-methyl 7-amino-6-chloro-1,3-benzodioxole-4-carboxylate (compound 22) was also prepared.

Provenance & Evidence