1,3-Dihydro-1-(4-piperidinyl)-2H-benzimidazol-2-one → 1-[1-(2-Methyl-7,8-dihydro-1,6,9-trioxa-3-aza-cyclopenta[a]naphthalen-8-ylmethyl)-piperidin-4-yl]-1,3-dihydro-2H-benzimidazol-2-one

Participants

Reaction Conditions

Reaction Steps

(8R)-2-Methyl-7,8-dihydro[1,4]dioxino[2,3-g][1,3]benzoxazol-8-ylmethyl 4-methylbenzenesulfonate (0.43 g, 1.14 mmole) and 4-(2-keto-1-benzimidazolinyl)-piperidine (0.77 g, 3.54 mmole) were combined in 10 mL of DMSO under nitrogen. This solution was heated to 82° C. under nitrogen for 4 hours. After completion, the reaction was allowed to cool to room temperature and was partitioned between ethyl acetate and saturated aqueous sodium bicarbonate. The organic phase was washed with brine, dried over sodium sulfate and concentrated in vacuum. The resulting crude oil was column chromatographed on silica gel using first methylene chloride to remove impurities and then 1% methanol/methylene chloride to elute 0.4 g of the (S)-enantiomer of the title compound, m.p. 218-220° C.

Provenance & Evidence