Organic Syntheses, CV 5, 663
Submitted by W. R. Benson
1, E. T. McBee
2, and L. Rand
2.
Checked by B. C. McKusick and T. J. Kealy.
1. Procedure
Twenty grams (0.079 mole) of iodine and
90 ml. of dried dioxane (Note
1) are placed in a
wide-mouthed, screw-cap, brown bottle of 150–200 ml. capacity. Most of the
iodine dissolves.
Eighteen grams (0.087 mole) of thoroughly dried N-silver succinimide (Note
2) is added, and the bottle is shaken vigorously for several minutes. The mixture is occasionally shaken in the course of an hour and then is warmed in a
water bath at 50° for 5 minutes. It is now filtered hot through a
Büchner funnel into a
500-ml. filter flask well wrapped with black paper or
aluminum foil. The
silver iodide that is collected is washed with a
10-ml. portion of warm dioxane.
Carbon tetrachloride (200 ml.) is added to the combined filtrates in the
filter flask, and the solution is chilled overnight at −8° to −20°.
N-Iodosuccinimide separates as colorless crystals. It is collected on a Büchner funnel with as little exposure to light as possible, washed with
25 ml. of carbon tetrachloride, and dried with suction. After being dried overnight in the dark at 25° (1 mm.) the
N-iodosuccinimide weighs
14.3–15.1 g. (
81–85% yield) and melts with decomposition at
193–199° (Note
3).
2. Notes
1. 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. Discussion
4. Merits of Preparation
N-Iodosuccinimide reacts with enol acetates derived from ketones to give α-iodoketones, and the reaction has found application in the steroid field.
4,6 The iodination of the enol acetates seems to proceed by an ionic mechanism, and preliminary work indicates that
N-iodosuccinimide is not capable of at least some of the radical-chain iodinations analogous to radical-chain brominations brought about by
N-bromosuccinimide.
4 N-Iodosuccinimide has also been used for the iodination of
purine nucleosides7 and of
fluorenone.
8 Iodination of 2-hydroxy-3-(β-alkylvinyl)-1,4-naphthoquinones results in an unusual replacement of a vinyl hydrogen.
9
This preparation is referenced from:
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