Lithium diisopropylamide → (S)-5,11-Dihydro-5-(1-[4-methylphenylsulphonyl]-2-pyrrolidinylmethyl)dibenzo[b,e][1,4]thiazepine

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Reaction Steps

Lithium diisopropylamide (4.3 ml of a 1.5M solution in hexane) was added to a solution of 5,11-dihydrodibenzo[b,e][1,4]thiazepine (see Example 1 for source) (1.0 g) in DME (25 ml) and the mixture stirred at room temperature for 15 minutes, treated with (S)-1-(4-methylphenylsulphonyl)-2-(4-methylphenylsulphonyloxymethyl)pyrrolidine (3.9 g) (prepared by the method of P. Karrer and K. Ehrhardt, Helv. Chim. Acta, 34, 2202 (1951)), heated under reflux for 2.5 hours, allowed to cool to room temperature, quenched with 2M hydrochloric acid and extracted with ethyl acetate. The organic extract was washed with water, dried over sodium sulphate and evaporated under reduced pressure. The residue was purified by chromatography on silica gel, performing a gradient elution initially using hexane as eluant and changing to hexane/ethyl acetate (90:10). Appropriate fractions were combined and evaporated under reduced pressure to give the title compound as a colourless solid, (0.93 g, 44%), m.p. 88°-90° C., [α]589 25 -115° (c=0.62 in ethanol).

Provenance & Evidence