The
tert-butyloxycarbonyl (
Boc) group is used as a
protecting group for
amines in
organic synthesis.
Common amine protection methods • Simple rapid stirring of a mixture of the amine and
di-tert-butyl dicarbonate (Boc2O) suspended in water at ambient temperature, an example of an
on-water reaction. • Heating a mixture of the amine to be protected and di-
tert-butyl dicarbonate in
tetrahydrofuran (THF) at 40 °C • Add the amine to
sodium hydroxide and di-
tert-butyl dicarbonate in water and THF at 0 °C then warm to ambient temperature. • Heating a mixture of the amine to be protected and di-
tert-butyl dicarbonate in a biphasic mixture of chloroform and aqueous sodium bicarbonate at reflux for 90 minutes. • Add the amine to di-
tert-butyl dicarbonate,
4-dimethylaminopyridine (DMAP), and
acetonitrile (MeCN) at ambient temperature : BOC-protected amines are prepared using the reagent
di-tert-butyl-iminodicarboxylate. Upon deprotonation, this reagent affords a doubly BOC-protected source of NH, which can be
N-alkylated. The approach is complementary to the
Gabriel synthesis of amines.
Common amine deprotection methods • Mix the protected
carbamate to be deprotected with 3 M
hydrochloric acid (HCl) in
ethyl acetate for 30 min at ambient temperature • Heat the carbamate in a mixture of aqueous hydrochloric acid and
toluene at 65 °C • Dissolving desired protected compound in a 50/50 mix of
dichloromethane and
trifluoroacetic acid : ==References==