[moviestarr2k5]

Hi, I have a problem with one of the steps of a multistep sysnthesis.

I have a molecule (C) C₁₇H₂₁NO
here is the structure


This molecule is treated with acetic anhydride under reflux the reaction mixture is decomposed with water
Ether extraction yields only a hydrocarbon (D) C₁₄H₁₂
Examination of the residual solution shows the presence of dimethylamine  (C₂H₇N)

How is molecule D formed from C and what happened to the carbon atom not accounted for in the transformation of C into D

Thank you very much for your help