Novel neplanociu A analogues modified at the 6'-pition, ie, 6'-deoxy analogues (2, 3, 6, 9, 20), 6'-0-methylneplan& A (15), and 6 '-C-methylneplanocin A's (22a and 22b) have been synthesized and evaluated for their antiviral activity in a wide variety of DNA and RNA virus systems. These compounds showed an activity spectrum that conforms to that of S- adenoeylhomocyateine hydrolase inhibitors. They were particularly active against pox-( ...