CH(CH 3) CH 3, isobutane, substitution occurring at the medial atom.
CH(CH3) CH2 CH31 from isobutane we may also derive two compounds, one identical with (2), and a new one (3) CH 3 (CH 3)C(CH 3)CH 3.
Isobutyl alcohol, (CH 3) 2 CH CH 2 OH, the butyl alcohol of fermentation, is a primary alcohol derived from isobutane.