N-Bromosuccinimide

  • NBS
  • N- Brombutanimid
  • 1-bromo- 2 ,5- pyrrolidinedione

Colorless, orthorhombic crystals

Fixed

2.10 g · cm -3

174-179 ° C

14.8 hPa ( 20 ° C)

  • Poorly in water ( 14 g · l-1 at 25 ° C ), diethyl ether, benzene, and carbon tetrachloride
  • Soluble in acetone and ethyl acetate,

Risk

-335.9 KJ / mol

Template: Infobox chemical / molecular formula search available

N-bromosuccinimide, usually abbreviated as NBS, the brominated on the nitrogen imide of succinic acid.

Production and representation

NBS can be prepared by treating the succinimide with elemental bromine in the presence of sodium hydroxide solution at 0 ° C.

Properties

NBS is little in water, but readily soluble in most organic solvents. NBS is not stable and should be stored in the dark at 2-8 ° C. Strong mechanical and / or thermal stress NBS may decompose explosively in bromine and nitrogen oxides.

Because of the relatively high electronegativity of the nitrogen to bromine, reinforced by the two adjacent carbonyl groups, the N- Br bond is polarized. In this case, the bromine carries a partially positive charge and can be easily removed. Therefore, NBS is used in many applications in organic chemistry.

Use

In the literature three applications are described mainly:

NBS reacts with allylic and benzylic protons light under substitution. This reaction is known as a Wohl-Ziegler reaction. Elemental bromine, however, reacts with the addition with the corresponding alkenes or core substitution with the aromatics.

NBS in aqueous dioxane is an extremely selective oxidant. In contrast to reagents such as the Cornforth reagent ( PDC) and pyridinium chlorochromate (PCC ), secondary alcohols in preference to primary alcohols in very good yields oxidized.

Alkenes react in aqueous dimethyl sulfoxide (DMSO ) to form the bromohydrins, called daltons reaction. These are important starting materials for the formation of epoxides. In anhydrous DMSO is obtained, however bromoketones. In the case of enol ether to give the α - Bromcarbonsäureester, can be the starting materials for the important Reformatsky reaction.

In the literature, numerous other uses are described.

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