... J. Heterocyclic Chern., 23, 669 (1986). 2,3-Diaminopyridine (13) and 3,4-diaminopyridine (8) are important intermediates that have been used to pre- pare heterocycles with demonstrated antiviral [ 1,2], cardio- vascular [3], antimicrobial [4 ... I] 0. P. Babbar and BL Chowdhury, J. Sci ...