H2 N−CH2−COOH\mathrm{H}_{2} \mathrm{~N}-\mathrm{CH}_{2}-\mathrm{COOH}H2 N−CH2−COOH
H2 N−CH(CH3)−COOH\mathrm{H}_{2} \mathrm{~N}-\mathrm{CH}\left(\mathrm{CH}_{3}\right)-\mathrm{COOH}H2 N−CH(CH3)−COOH
CH3−CHOH−CH3\mathrm{CH}_{3}-\mathrm{CHOH}-\mathrm{CH}_{3}CH3−CHOH−CH3
CH3−CH2−COOH\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{COOH}CH3−CH2−COOH
