Secret: Time is NEVER on your side when you are buying. Never forget that. Keep in mind that if you are looking to explore the viability of a purchase, a good starting point is the LOI. Once you get beyond the "overview" of what you and the seller are looking for, detail everything out in the purchase contract, and keep all of the above in mind when doing so.
Closing shall be on or before specified date at a place and time agreeable to all parties. From the signing of this letter of intent until Closing, Seller shall operate its business under the normal course of business and Seller shall not present, enter into discussions, or offer to sell its business to any other party. This paragraph shall be binding on the parties although the balance of this letter only expresses the intentions of the parties.