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Title: Synthetic studies of some varied structural systems of biologically potent polynitrogen heteropolycyclics
Authors: Gupta, Shallu
Gupta, Poonam
Sachar, Anand
Sharma, Rattan L
Keywords: Knoevenagel
subsequent Michael and heterocyclisation reactions
‘<i style="">ortho</i>’ and ‘<i style="">ortho</i> and<i style=""> peri</i>’ fused heteropolycyclics
Issue Date: Sep-2010
Publisher: CSIR
Abstract: Four-component one pot cyclocondensation of aromatic aldehydes <b style="">1,</b> malononitrile <b style="">2</b>, barbituric acid <b style="">3</b> and ammonium acetate in methanol after initial Knoevenagel, subsequent Micheal and final heterocyclisation reactions give substituted and functionalized pyrido[2,3-<i style="">d</i>]pyrimidine derivatives <b style="">4</b>. These pyridopyrimidines on reaction with various active methylene compounds result in the formation of differently functionalized and diversly substituted linear tricyclic pyrimidonaphthyridines <b style="">5-7</b> and <b style="">9-10</b>, linear tetracyclic benzo[<i style="">b</i>]pyrimidonaphthyridines <b style="">8</b> and dipyrimidonaphthyridines <b style="">11</b> as a result of final heterocyclization through either simple cyclocondensation or cyclodehydration,<i style=""> etc</i>. The compounds of system <b style="">7/10</b> and two compounds of system <b style="">8 </b>with suitable functionalities on further condensation with formamide, generate the novel angularly fused tetracyclic dipyrimidonaphthyridines <b style="">12/14</b> and ‘<i style="">ortho </i>and <i style="">peri</i>’ fused pentacyclic pyrimidonaphthyridinoquinazolines <b style="">13</b> respectively, all hitherto unknown or not reported in literature. Compounds <b style="">4 </b>and <b style="">5 </b>on condensation with formamide can close the recurring generation of the CN and other reactive functionality on the products resulting in the production of tricyclic pyrido [2,3-<i style="">d</i>;6,5-<i style="">d</i>′]dipyrimidine <b style="">15 </b>from <b style="">4 </b>and two differently fused linear and angular tetracyclic dipyrimidonaphthyridine systems <b style="">16 </b>and <b style="">17 </b>from <b style="">5 </b>similar to the systems <b style="">11 </b>and <b style="">12/14</b> respectively. Either of the latter two systems on heterocyclodehydration with boiling formic acid produce same ‘<i style="">ortho</i> and <i style="">peri</i>’ fused pentacyclic novel heterocyclic system 1,3,4,6,7,8,9,11-octazabenzo[<i style="">de</i>]naphthacene <b style="">18</b>.
Description: 1243-1256
ISSN: 0975-0983(Online); 0376-4699(Print)
Appears in Collections:IJC-B Vol.49B(09) [September 2010]

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