... 1559 J. Heterocyclic Chem., 27, 1559 (1990 ... The resulting 4-piperazinyl-substi- tuted heterocycles 3 could then be treated with hydrazine in refluxing isoamyl alcohol to displace the 2-chloro func- tionality. ... H. Chang, JP Williams, R. MacDonald, J. Knapczyk and M. Carman, J. Org ...