(S)-2-Amino-N1,N1-diethylpentanediamide; Pentanoic acid, 4-amino-5-(diethylamino)-5-oxo-, (4S); (4S)-4-Amino-5-(diethylamino)-5-oxopentanoic acid; Pentanoic acid, 4-amino-5-(diethylamino)-5-oxo-, (S)