Pure 2-halopentane can be obtained by the application of sodium halide to 2-pentanol tosylate but the reaction takes a long period and the yield is poor. A new advantageous method was devised so as to eliminate the use of expensive 2-halopentane by the condensation of methyl propyl ketone (III) and ethyl cycanoacetate (IV) and followed by the reduction by which ethyl (1-methylbutyl) cyanoacetate (VI) was obtained in approx. 64% yield. Thiopental Sodium is obtained from (VI) by the ordinary procedures.
