Ammonia → Boc-D-phenylalanylproline (6-amidino-3-picolyl)amide

Participants

Reaction Steps

1.15 g (16.5 mmol) of hydroxylamine hydrochloride were suspended in 5 ml of ethanol, 1.2 g of 25% strength ammonia solution were added, and the mixture was stirred for 10 min. After addition of 45 ml of ethanol, the precipitated salt was filtered off with suction and 3.14 g (6.6 mmol) of the above compound (stage c) were added to the solution. The hydroxyamidine compound separated out after a short time and, after stirring for 30 minutes, was filtered off with suction and washed with a little cold water and ethanol. The residue moist with ethanol was dissolved in 40 ml of ethanol and 8 ml of glacial acetic acid, 250 mg of 10% Pd/C were added and hydrogenation was carried out at about 50° C. After 5 hours, TLC (CH2Cl2/MeOH/50% strength acetic acid, 20/5/1) showed no detectable starting material.

Provenance & Evidence