In a
1-l. round-bottomed flask is placed
760 g. (844 cc.) of concentrated aqueous ammonia (sp. gr. 0.9) and to this is slowly added
150 g. (0.77 mole) of α-bromocaproic acid (Note
1). The flask is well stoppered and allowed to stand in a warm place (50-55°) for twenty to thirty hours. The amino acid separates and is filtered off with suction and washed with
methyl alcohol (Note
2). This crop of crystals weighs
51–56 g. The aqueous filtrate is evaporated nearly to dryness on a
steam bath and then treated with about
250 cc. of methyl alcohol. This precipitates a second crop of amino acid contaminated with
ammonium bromide. On washing with
methyl alcohol and recrystallizing from water, there is obtained
10–15 g. more of pure product. The total yield is
63–68 g. (
62–67 per cent of the theoretical amount).