CH3NH2\mathrm{CH}_{3} \mathrm{NH}_{2}CH3NH2
C2H5NHC2H5\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NHC}_{2} \mathrm{H}_{5}C2H5NHC2H5
(CH3)3 N\left(\mathrm{CH}_{3}\right)_{3} \mathrm{~N}(CH3)3 N
CH3NHC2H5\mathrm{CH}_{3} \mathrm{NHC}_{2} \mathrm{H}_{5}CH3NHC2H5