c
\({C_2}{H_5}{\mkern 1mu}  - {\mkern 1mu} {\mkern 1mu} N{\mkern 1mu} {\mkern 1mu}  = {\mkern 1mu} C{\mkern 1mu} {\mkern 1mu}  = {\mkern 1mu} {\mkern 1mu} O{\mkern 1mu} {\mkern 1mu} \xrightarrow{{KOH}}{\mkern 1mu} \) \({C_2}{H_5}N{H_2}{\mkern 1mu} \xrightarrow{{{{(C{H_3})}_3}C - MgBr}}\) \(\mathop {C{H_3}{\mkern 1mu}  - {\mkern 1mu} \mathop {\mathop {{\text{ }}C}\limits_{\mathop {{\text{ }}|}\limits_{\,\,\,\,\,\,C{H_3}} } }\limits^{\mathop {{\text{ }}|}\limits^{\,\,\,\,H} } {\mkern 1mu}  - {\mkern 1mu} C{H_3}}\limits_{Isobutane} \)