Synthesis of N-bromosuccinimide (NBS) and N-Iodosuccinimide (NIS)N-bromosuccinimide (NBS)
1.62mol (160g) succinimide is dissolved in a mixture of 1.60mol (64g) NaOH, 300g crushed ice and 400ml water. Cool the mixture in an ice bath, and add 85ml (1.65 mol, 264g) Br2 at once while stirring violently. Stir for two more minutes, then filter the precipitated product and wash with ice water. Dry in a desiccator. Yield 75-81%. Don't clean up NBS too much, the stinky yellow stuff still containing a bit of Br2 works best. N-Iodosuccinimide (NIS)
To a solution of 39.2g of succinimide in 1200ml of boiling water was added 51.0g of freshly precipitated silver oxide, the mixture was filtered and the silver salt was allowed to crystallize. Filtration and washing with cold water furnished 45.0g of the silver salt of succinimide suitable for the iodination step. The finely powdered salt (49.5g) was added in portions with stirring to a solution of 50.8g of iodine in 300ml of acetone, the temperature being maintained at 5-10°C. After decolorization (30 min.), the silver iodide was filtered, the solvent was removed under reduced pressure at room temperature and the residue was washed with ether, yielding 43g of N-iodosuccinimide with mp 189-191°C. An analytical sample (85% recovery) was obtained by dissolving in the minimum quantity of hot dioxane and precipitating with carbon tetrachloride; colorless needles, mp 200-201°C. Ref: JACS 75, 3493 (1953) Another preparation of N-Iodosuccinimide (Organic Syntheses) |