The starting material that produce pentanamine by Hoffmann bromamide reaction is

Hoffmann developed a method for preparation of primary amines by treating an amide with bromine in an aqueous or ethanolic solution of sodium hydroxide. In this degradation reaction, migration of an alkyl or aryl group takes place from carbonyl carbon of the amide to the nitrogen atom. The amine so formed contains one carbon less than that present in the amide

Hence, for the formation of pentanamine through hoffmann bromamide degradation.The starting compound should be hexanamide.

The reaction is given below:

${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CONH}}_2+{\mathrm{Br}}_2+4\mathrm{NaOH}\to {\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{NH}}_2+2\mathrm{NaBr}+{\mathrm{Na}}_2{\mathrm{CO}}_3+2{\mathrm{H}}_2\mathrm{O}$