When compounds of the type represented by A are allowed to stand in pentane, they are converted

Question:

When compounds of the type represented by A are allowed to stand in pentane, they are converted to a constitutional isomer.

Hydrolysis of either A or B yields RNHCH2CH2OH and p-nitrobenzoic acid. Suggest a reasonable structure for compound B, and demonstrate your understanding of the mechanism of this reaction by writing the structure of the key intermediate in the conversion of compound A to compound B.