Methanol → 2-(Diphenylmethyl)-5-oxa-2,8-diazaspiro[3.5]nonane

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Reaction Steps

Borane methyl sulfide complex (2M in THF, 10.7 mL) was added to a solution of 2-benzhydryl-5-oxa-2,8-diazaspiro[3.5]nonan-7-one (example 33, step e) (2 g) in dry THF (40 mL) and the resultant solution was stirred at 70° C. under nitrogen for 50 minutes. The mixture was cooled to room temperature and treated dropwise with methanol (40 mL) followed by N1,N2-dimethylethane-1,2-diamine (3.43 g). The mixture was heated at 70° C. for 6 hours. The solvent was removed under reduced pressure and the residue partitioned between ethyl acetate and brine. The organic layer was dried over sodium sulphate, filtered and the solvent evaporated under reduced pressure. The crude product was purified by flash silica chromatography using 1% triethylamine and 5% methanol in dichloromethane as solvent. Pure fractions were evaporated to dryness to afford the subtitled compound. Yield 1.35 g.

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