Aluminium lithium hydride → methoxy-3-methyl-2,3,4,5-tetrahydro-1H-benzo[d]azepine

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Reaction Steps

Dissolve methoxy-3-methyl-1,3,4,5-tetrahydrobenzo[d]azepin-2-one (375 g, 183 mmol, 1.0 eq) in THF (2.5 L) and add the solution via an addition funnel over 1 hour to slurry of lithium aluminium hydride (LAH) (175 g, 457 mmol, 2.5 eq) in ether/THF (4.5 L/2 L) in a 22 L reaction vessel under nitrogen while cooled in an ice/acetone bath. Add the starting amide at a rate to maintain the reaction temperature below 30° C. Stir the resulting mixture for 3 hours at room temperature under nitrogen. The reaction is determined to be complete by TLC. Cool the reaction mixture in an ice/acetone bath and quench slowly over 2 hours (off-gassing, exothermic) with water (175 mL) and 5.0 N NaOH solution (350 mL) added in succession. Filter the slurry and wash the solids with THF. Add sodium sulfate to the filtrate to remove any excess water, and then filter. Concentrate the filtrate down under vacuum to a dark oil to obtain the product methoxy-3-methyl-2,3,4,5-tetrahydro-1H-benzo[d]azepine (360 g, quantitative yield).

Provenance & Evidence