6-Bromoisatin, prepared from 2-nitroaniline in 7 steps, was condensed with ethyl 4-phthalimidoacetoacetate (10) under Knoevenagel conditions to give ethyl 2-(6-bromo-2-oxo-3-indolinylidene)-3-oxo-4-phthalimidobutyrate (11) in 83% yield. Reduction of 11 with sodium hydrosulfite in boiling EtOH afforded an enolized diastereomeric mixture of the oxindole derivative 12 (90%). Careful treatment of 12 with hydrazine hydrate followed by hydrolysis (10% HCl) gave amino-ketone hydrochloride 13 (49%).
