A solution of
monoethanolamine (1.2 g) (substitute with the appropriate amount of Tris) in CH2C12 (5 mL) was added
dropwise over a period of 20 min to a cooled mixture of
HNO3 (3.8 g) and CH2C2 (25 mL). The temperature of the
bath was maintained in the range 0--5 deg C. Then the reaction
mixture was stirred at this temperature for 15 rain, acetic
anhydride (3 mL) was added dropwise, and the mixture was
stirred for an additional 15 min. The precipitate was separated
and dried in a vacuum desiccator over P205 to give 3.1 g
(91.2 %), m.p. 100--102 deg C. After recrystallization
from EtOH, the yield was
69--72 %, m.p. 102--103 deg C |