# What are all the structural isomers of a tertiary amine with the sum formula C6H15N?

According to the solutions there exist 7 different structural isomers 'containing 3 degree amines' for the molecular formula $\ce{C_6H_{15}N}$

I tried and made a few, here are those

I have been trying since an hour and all I made were the repetitions of these 5 only. Could anyone suggest me the remaining 2?

• There is a methyl ethyl propyl amine and methyl ethyl isopropyl amine . – LDC3 Apr 4 '15 at 5:05
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