Mo. Rev. Stat. § 473.280

Whenever any note, bond, account, or other indebtedness belonging to the estate of any decedent is secured by mortgage, deed of trust, vendor's lien or other lien on any property, and the same is due and unpaid, the administrator or executor of the estate, under the order of the court, may purchase the property at the sale made under the mortgage, deed of trust or other lien, at a price not exceeding the amount due the estate on the note, bond, account or other indebtedness.