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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]
The classic example is the conversion of glucose to arabinose as shown below. The reaction is named after the German chemist Alfred Wohl (1863–1939). The Wohl degradation. Let's say we have a kiliani-fischer synthesis, it basically removes the row of the C2 carbon, it shortens the carbon chain by one carbon.
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.
Free-radical reactions depend on one or more relatively weak bonds in a reagent. Under reaction conditions (typically heat or light), some weak bonds homolyse into radicals, which then induce further decomposition in their compatriots before recombination. Different mechanisms typically apply to reagents without such a weak bond.
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.
Ruff degradation is a reaction used to shorten the open chain forms of monosaccharides. [1] It is functionally the reverse reaction of Kiliani-Fischer synthesis.. In 1898, Otto Ruff published his work on the transformation of D-Glucose to D-Arabinose later called the Ruff degradation.