An-NH2 group when not the principal group, is named by the prefix amino CO,H HoN- COH NH2 NH2 2-Aminobutanoic acid 2. 6-Diaminobenzoic acid NH 4-Amino-2-butanoneOrganic Chemistry Organic Chemistry Xiamen Xiamen University University An -NH 2 group, when not the principal group, is named by the prefix amino-. CO 2 H NH 2 H 2 N CO 2 H O NH 2 2- A m i n o b utanoic acid NH 2 2,6-Di a m i n o b enzo ic acid 4- A m i n o-2-butano n e