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Upstream product

• 128-08-5 N-Bromosuccinimide 
• 558-37-2 tert-butylethylene 

Relevant academic research and scientific papers

Excited-State ? Succimidyl and Glutarimidyl Radicals: Reversible Ring Opening

The free-radical isomerization of N-bromosuccinimide to β-bromopropionyl isocyanate has been examined.Of the two varieties of succinimidyl radical (S? or S?), only the ? excited state undergoes the ring opening to the β propionyl isocyanatyl radical.The conversion optimally takes place in >95percent yield.The dependence of NBS concentration along with results obtained from deuterium labeling studies indicate that the ring opening of S? is a reversible process.This explains the failure of N-chlorosuccinimide to produce β-chloropropionyl isocyanate, as well as the increase in ring-opened product for N-bromosuccinimides upon methyl substitution at the 2- and/or 3-position of the succinimidyl ring, since the open-chain radical intermediates are more stable.In the N-bromoglutarimide system, methyl groups on the 2-position are required for the glutarimidyl radicals to undergo the isomerization, ultimately producing isocyanates.The radical-chain nature of these systems is confirmed.

Reactions of a Graded Set of Radicals with N-Bromosuccinimide; Two Transition States

The reactions of N-bromosuccinimide with a series of radicals have been studied.These reactions fall into two categories, the more reactive radicals producing ?-succinimidyl and the less reactive radicals producing ?-succinimidyl.The threshold for the changeover from one reaction domain to the other occurs with radicals less reactive than secondary alkyls.These results are interpreted with two transition states, an in-line transition state for the more reactive radicals and an out-of-plane transition state for the less reactive radicals. An upper limit of 18 kcal/mol is established for the enthalpy difference, HS? - HS?.Two new methods for generating S? radicals are indicated.