Novel synthesis, properties, and NAD+-NADH type redox ability of 1,3-dimethylcyclohepta[4,5]pyrrolo[2,3-d]pyrimidine-2,4(1,3H)-dionylium ions annulated with additional pyrrolo[2,3-d]pyrimidine-1,3(2,4H)-dione and furan analogue, and their hydride adducts