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. The dioxane is purified only by the use of sodium
strips and distillation.3 The checkers used a newly opened bottle of "Spectroquality
Reagent" dioxane (Matheson, Coleman and Bell) without further
treatment.
2. N-Silver succinimide was prepared by the method of Djerassi and
Lenk.4 The checkers rapidly added a solution of 64 g. (1.6 moles) of
sodium hydroxide in 300 ml. of water dropwise to a stirred solution of
249 g. (1.47 moles) of silver nitrate in 700 ml. of water at room
temperature. The silver oxide that formed was separated on a Büchner
funnel and washed with water. The moist oxide was added in one portion
to a boiling solution of 133 g. (1.34 moles) of succinimide in 4 l. of
water. The reaction vessel was wrapped with aluminum foil in order to
exclude as much light as possible. After 45 minutes, the suspension was
filtered through a heated Büchner funnel into a filter flask also
wrapped with aluminum foil. The filtrate was allowed to stand at room
temperature overnight, during which time N-silver succinimide
crystallized. The N-silver succinimide was separated on a Büchner
funnel, dried in air under suction, and ground to a powder. After being
dried in a vacuum oven for 1 hour at 110°, it weighed 128 g. (47%).
N-Silver succinimide should be stored in a brown bottle.
3. This material is pure enough to use in the preparation of
a-iodoketones. The checkers found that, after one recrystallization from
a mixture of dioxane and carbon tetrachloride, the N-iodosuccinimide
melted with decomposition at 195-200°. Pure N-iodosuccinimide is
reported to melt at 200-201°.4
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