can be written as \[{{H}_{3}}C\underset{3,\text{ }3-dimethyl-4-heptanone}{\mathop{-\overset{\begin{smallmatrix} C{{H}_{3}} \\ | \end{smallmatrix}}{\mathop{\underset{\begin{smallmatrix} | \\ \underset{2}{\mathop{C}}\,{{H}_{2}}-\underset{1}{\mathop{C}}\,{{H}_{3}} \end{smallmatrix}}{\mathop{C}}\,}}\,-\overset{\begin{smallmatrix} O \\ || \end{smallmatrix}}{\mathop{\underset{4}{\mathop{C}}\,}}\,-}}\,\underset{5}{\mathop{C}}\,{{H}_{2}}-\underset{6}{\mathop{C}}\,{{H}_{2}}-\underset{7}{\mathop{C}}\,{{H}_{3}}\]