What is N-Iodosuccinimide?

General Description

N-iodosuccinimide is a five-membered cyclic dicarboximide compound having an iodo substituent on the nitrogen atom. It is a dicarboximide and a pyrrolidinone. It derives from a succinimide, and is the iodine analog of N-chlorosuccinimide (NCS) and N-bromosuccinimide (NBS).  N-Iodosuccinimide (NIS) is an iodinating agent that is used for various electrophilic iodinations and as source for iodine in radical reactions.

N-iodosuccinimide is highly substituted iodobenzenes prepared via an efficient 2-step process from 1,6-diynes. Used with TFA to chemoselectively hydrolyze thioglycosides to 1-hydroxyglycosides. Used in the synthesis of vinyl sulfones from olefins and benzenesulfinic acid.

Reactions

N-Iodosuccinimide (NIS) is an iodinating agent that is used for various electrophilic iodinations and as source for iodine in radical reactions.

N-Iodosuccinimide is the least reactive of the N-haloamides in aromatic substitution. N-Iodosuccinimide does not act as an iodinating agent in pure dimethyl sulfoxide or N-ethylacetamide. On the other hand, butyl disulfide and a number of other sulfur-containing compounds are effective catalysts at low concentration for the iodination of guanosine derivatives using N-iodosuccinimide. This catalytic effect is observed when dimethyl sulfoxide is used as the solvent,but not when N-ethylacetamide is used.

Preparation Method

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).