Condensation of 2,3-pyridinediamines with acetonylacetone

The reaction of 2,3-pyridinediamine 1a and its 5-bromo analogue 1b, indepen dently, with acetonylacetone leads to the formation of 1:1 condensation pro ducts irrespective of the molar ratios employed. The condensation products have been assigned 2-amino 2a and 5-bromo-2-amino-3 (2',5'-dimethylpyrrolyl )pyridine 2b structures. Authentic chemical evidence is given in support of the claim for these structures ruling out the equally probable alternative structure 3 for these compounds. Attempted studies on the reactivity of th e latter compounds towards electrophilic reagents such as acetic anhydride, benzoyl chloride, and arylsulphonyl chlorides have been described.