acid required a melt reaction providing a 78% yield of 3-oxodihydroquinoxalinyl-2-urea 22 and side products. Despite numerous reaction steps, most of these uncatalyzed stoichiometric reactions proceeded quantitatively in the solid state to give only one product (plus water), with unsurpassed atom economy. If catalysis with HCl was tried, the results were inferior. If melt reactions were required it appeared