3a,4,5,7a-Tetrahydro-2-benzofuran-1,3-dione → N-[4-chloro-2-fluoro-5-ethoxymethylphenyl]-3,4,5,6-tetrahydrophthalimide

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Reaction Steps

Tetrahydrophthalic anhydride (0.58 g, 0.0039 mole), and 4-chloro-5-ethoxymethyl-2-fluoroaniline in glacial acetic acid from Step C was heated at 100° C. overnight. Acetic acid was removed under reduced pressure. The residue was dissolved in ethyl acetate (100 ml) and washed successively with a saturated aqueous solution of sodium bicarbonate (5×50 ml) and a 10% aqueous solution of hydrochloric acid. The dried (magnesium sulfate) organic layer was concentrated under reduced pressure. The residue was passed through a column of silica gel eluting with ethyl acetate:heptane (3:17). Appropriate fractions were combined and concentrated under reduced pressure yielding N-[4-chloro-2-fluoro-5-ethoxymethylphenyl]-3,4,5,6-tetrahydrophthalimide as an amber solid, m.p. 89°-91° C. The nmr spectrum was consistent for the proposed structure.

Provenance & Evidence