N-Bromosuccinimide reaction of olefins
NBS can olefin 1 in aqueous solution reaction of hydroxy alkyl bromide 2. The optimal reaction condition is at 0 ° C under an olefin dissolved in dimethyl sulfoxide, dimethoxyethane, tetrahydrofuran, tert-butanol, 50% aqueous solution of any one of the segments joined NBS. The reaction mechanism is: i) an onium bromide ion generation; ii) the nucleophilic attack of water molecules. Stereoselectivity for the trans-adduct in accordance with the law Markov.
The products of the reaction include the α-bromo ketone and two bromo compound. The new NBS purified by recrystallization can reduce the formation of these by-products. If no water was added, and the addition of other nucleophiles may bifunctional synthesis of other compounds.
Hofmann rearrangement reaction of bromide
N-bromosuccinimide in a strong base (e.g., 1,8 - diazabicyclo [5.4.0] undec-7 - ene (DBU)) state can be re-primary amide by Hofmann discharge reaction intermediate isocyanates. The isocyanate compound and a hydroxyl group (e.g., methanol) to form a readily hydrolyzable carbamate and separation.
More about:N-Bromosuccinimide suppliers
From:chemical reagent
No comments:
Post a Comment