Polycyclic Azines with Heteroatoms in the 1- and 3-Position. Part 42. Bis((2,4-dioxo-1,2,3,4-tetrahydroquinazolin-3-yl)alkyl)disulfanes and 3-(Mercaptoalkyl)quinazoline-2,4(1H,3H)diones: Synthesis by Ring Transformations and Antiviral