§ 278-a. Sale or exchange of certain real property or mortgage investments therein authorized. Trustees, executors, administrators, guardians, committees, conservators and all other persons or corporations holding trust funds or acting in a fiduciary capacity, corporations and private bankers organized under or subject to the provisions of the banking law, the superintendent of financial services as conservator, liquidator or rehabilitator of any such corporation or private banker organized under and subject to the provisions of the banking law, persons, partnerships and corporations organized under or subject to the provisions of the insurance law, the superintendent of financial services as conservator, liquidator or rehabilitator of any such person, partnership or corporation organized under or subject to the provisions of the insurance law who or which (1) own any property on which there is a building defined in the multiple dwelling law as an old law tenement or who or which hold a mortgage or other lien on such property, or

(2) own any property, improved or unimproved, or any mortgage or other lien thereon, within any section of a municipality included in a map showing sections containing areas for clearance, replanning and low rent housing, adopted by the planning commission of the municipality as a whole or part of the master plan, or

(3) own any property, improved or unimproved, or any mortgage or other lien thereon, within any section of a municipality which may be designated by the planning commission or the housing authority of the municipality as substandard or insanitary, may sell such property, mortgage or lien, and may, notwithstanding any other provision of law, receive and hold in exchange therefor securities issued by a corporation owning or acquiring title to such property, if such corporation shall agree in writing at the time of such sale, to reconstruct, improve, alter, repair or demolish such property or to construct a new building on such property, or on such property and on any contiguous property owned or to be acquired by such corporation.