Is it permissible for me to buy an apartment from a company that requires a reservation down payment to be deposited in the Islamic Transactions Branch of a usurious bank, and the return on this amount is used to purchase the land and cover the remaining costs, knowing that the amount will remain in the bank for a period during which it may accrue a return?

Purchasing an apartment in the manner described is an Istisna' (manufacturing) contract, which requires for its validity a precise description of the property to prevent ambiguity (Jahalah), such as specifying its type, size, location, and characteristics. Since the land upon which the apartment will be built is unknown or undefined at the time of the contract, this ambiguity invalidates the Istisna' contract. As for depositing the first installment in the bank, there is no objection to that if the bank is Islamic or its branch adheres to Sharia compliance.