Synthesis and evaluation of aborted and extended CC-1065 functional analogs - (+)-CPI-PDE-1, and (-)-CPI-PDE-1, (+)-CPI-PDE-1, and (-)-CPI-CDPI1, and (+/-)-CPI-PDE-i1, (+)-CPI-PDE-i1, and (-)-CPI-CDPI3 - preparation of key partial structures and definition of an additional functional-role of the CC-1065 central and right-hand subunits