CH2(NH2)COOH\mathrm{CH}_{2}\left(\mathrm{NH}_{2}\right) \mathrm{COOH}CH2(NH2)COOH
CH3CH(NH2)COOH\mathrm{CH}_{3} \mathrm{CH}\left(\mathrm{NH}_{2}\right) \mathrm{COOH}CH3CH(NH2)COOH
(CH3)2C=CHC\left(\mathrm{CH}_{3}\right)_{2} \mathrm{C}=\mathrm{CHC}(CH3)2C=CHC
CH3CH2COOH\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COOH}CH3CH2COOH