Succinimidyl carbonate reaction with amines

As alternatives to 4-nitrophenyl chloroformate, carbonyl diimidazole [100-102] or di-A-succinimidyl carbonate [103,104] can be used to convert polymeric alcohols into alkoxycarbonylating reagents suitable for the preparation of support-bound carbamates. Polystyrene-bound alkoxycarbonyl imidazole is less reactive than the corresponding 4-nitrophenyl carbonate, and sometimes requires heating to undergo reaction with amines. Additional activation of these imidazolides can be achieved by N-methylation (Entry 9, Table 14.7). 

Figure 378 A succinimidyl carbonate derivative of mPEG was first prepared through the use of phosgene to form a chloroformate intermediate. Reaction with NHS gives the amine-reactive succinimidyl carbonate— mPEG.

For the sake of increased stability and improved storage, somewhat less reactive alternatives have been prepared from the labile chloroformate. For example, 2-(trimethylsilyl)ethyl -succinimidyl carbonate has been used to prepare Teoc-protected amino acids in water or dioxane using sodium hydrogen carbonate or triethylamine as the base. - 2-(Trimethylsilyl)ethyl 4-nitrophenyl carbo-nate2 246 g commercially available reagent (mp 34-36 C) that reacts with amino acids in a mixture of aqueous sodium hydroxide and rert-butyl alcohol or dioxane. Simple amines can be acylated with triethylamine under anhydrous conditions [Scheme 8.105]. Teoc derivatives can also be prepared by an exchange reaction using an aryl carbamate derivative and 2-(trimethylsilyl)ethanol as shown in Scheme 8.106. ... 

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