CH3−NH−CH3\mathrm{CH}_{3}-\mathrm{NH}-\mathrm{CH}_{3}CH3−NH−CH3
CH3−NH2\mathrm{CH}_{3}-\mathrm{NH}_{2}CH3−NH2
CH3−CH2−NH2\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{NH}_{2}CH3−CH2−NH2
