The problem studied in this paper originates from a just-in-time environment where a new supplying mode, called Synchronous Delivery, has been introduced recently. We consider a multi-product single machine scheduling problem in which the total changeover costs has to be minimized. The products are of different types and a changeover cost is incurred whenever switching from one product type to another. For each product, the processing time is equal to one and its deadline is different from deadlines of all other products. We present five complexity results and propose dynamic programming and heuristic approaches to the problem. Computational results are given comparing two heuristics to the optimal solution given by the dynamic programming method.