Sulfuric Acid → 1,3-Dihydro-3-methyl-2H-3-benzazepin-2-one

Participants

Reaction Conditions

Reaction Steps

To a 5 L Morton flask under a strong nitrogen atmosphere was added H2SO4, (1.42 L) and N-methyl-N-(2,2-dimethoxyethyl)phenylacetamide (712 g, 3 mol) was added dropwise to the reaction flask which caused an exotherm (22 to 78° C.). The resulting reaction was then heated to 110° C. for 3 h then cooled to room temperature and transferred to a 20 L Morton flask. At less than 10° C., the reaction mixture was quenched with aqueous sodium hydroxide (9.18 L, 5 N). Extractive workup with ethyl acetate (2×2.85 L), drying with sodium sulfate followed by concentrating to a solid, provided 520 g (73.5%) of 3-methyl-2,3-dihydro-1H-3-benzazepin-2-one as a solid. This material may be recrystallized from MTBE for added purity to give a solid, mp=81-82° C.; (M+H)+=174.2.

Provenance & Evidence