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N-Bromosuccinimide or NBS is a chemical reagent used in radical substitution, electrophilic addition, and electrophilic substitution reactions in organic chemistry. NBS can be a convenient source of Br • , the bromine radical.
The Wohl–Ziegler reaction [1] [2] is a chemical reaction that involves the allylic or benzylic bromination of hydrocarbons using an N-bromosuccinimide and a radical initiator. [3] Best yields are achieved with N-bromosuccinimide in carbon tetrachloride solvent. Several reviews have been published. [4] [5]
In a free-radical addition, there are two chain propagation steps. In one, the adding radical attaches to a multiply-bonded precursor to give a radical with lesser bond order. In the other, the newly-formed radical product abstracts another substituent from the adding reagent to regenerate the adding radical. [3]: 743–744
Rather, it is formed by oxidation of dimethyl sulfide with an oxidant (NCS). The reaction mechanism of Corey–Kim oxidation Under Corey–Kim conditions allylic and benzylic alcohols have a tendency to evolve to the corresponding allyl and benzyl chlorides unless the alcohol activation is very quickly followed by addition of triethylamine .
Structure of N-bromosuccinimide, a common brominating reagent in organic chemistry. Like the other carbon–halogen bonds, the C–Br bond is a common functional group that forms part of core organic chemistry. Formally, compounds with this functional group may be considered organic derivatives of the bromide anion.
N-Iodosuccinimide (NIS) is a reagent used in organic chemistry for the iodination of alkenes and as a mild oxidant. [ 2 ] NIS is the iodine analog of N -chlorosuccinimide (NCS) and N -bromosuccinimide (NBS) which are used for similar applications.
It creates volatile compounds when mixed with glucose and amino acids at 90 °C. [9] It is a cofactor in tyrosine oxidation, though because a crude extract of animal liver is used, it is unclear which reaction catalyzed by which enzyme is being helped here. [10] For known roles in enzymatic reactions, see Vitamin C § Pharmacodynamics.
Several reagents can be substituted for bromine. Sodium hypochlorite, [4] lead tetraacetate, [5] N-bromosuccinimide, and (bis(trifluoroacetoxy)iodo)benzene [6] can effect a Hofmann rearrangement. The intermediate isocyanate can be trapped with various nucleophiles to form stable carbamates or other products rather than undergoing decarboxylation.