| Summary: | An oven-dried 1-L, two-necked, round-bottomed flask, equipped with a 3 cm football-shaped stir bar, a rubber septum and inert gas inlet connected to a manifold, is charged with o-nitrobenzenesulfonyl hydrazide (1) (Note 1) (20.0 g, shaped stir bar, a rubber septum and inert gas inlet connected to a manifold, is charged with o-nitrobenzenesulfonyl hydrazide (1) (Note 1) (20.0 g, 92.1 mmol, 1 equiv) under an argon atmosphere. Acetone (Note 2) (300 mL) is added via cannula and the resulting solution stirred at room temperature (24 °C). After 10 min, TLC (Note 3) analysis of the reaction mixture indicated full conversion of the starting material (hexanes:ethyl acetate = 1:2; Rf[subscript SM] = 0.2, Rf[subscript product] = 0.5, visualized with ceric ammonium molybdate). Aliquots of the solution are transferred to a 500-mL onenecked flask and the solvent is removed with a rotary evaporator (200 mmHg, 40 °C) to afford a yellow powder. Hexanes (100 mL), acetone (20 mL), and a 3-cm football-shaped stir bar are added and the suspension stirred for 10 min at room temperature. The white solid is collected by vacuum filtration (40 mm, Büchner funnel with fritted disc, medium porosity) and washed with hexanes (2 × 60 mL, 24 °C). The white solid is then transferred to a 250-mL flask and dried in vacuo (7 mmHg, 24 °C) for 24 h to afford N-isopropylideneN'-2-nitrobenzenesulfonyl hydrazine (2) (Note 4) (22.5 g, 87.4 mmol, 95%) as an off-white solid.
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