• Title/Summary/Keyword: Imidazopyrazolopyrimidines

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Synthesis of Some Imidazopyrazolopyrimidines, Pyrazolopyrimidopyrimidines and Pyrazolopyrimidothiazines

  • Elkhawaga, A.M.;Kamal El-Dean, A.M.;Radwan, M.;Ahmed, M.M.
    • Bulletin of the Korean Chemical Society
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    • v.30 no.3
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    • pp.561-566
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    • 2009
  • Chloroacylation of 3-amino-2-phenylpyrazole-4-carboxamide (2) using chloroacetyl-(propionyl) chloride affording 6-chloromethyl(ethyl)-1-phenylpyrazolo[3,4-d]pyrimidin-4[5H]-one (3) or (6). Chlorine atom in compound (3) or (6) underwent nucleophilic substitution reaction with primary or secondary amines to give 6-alkyl(aryl)aminomethyl(ethyl)-1-phenylpyrazolo[3,4-d]pyrimidin-4[5H]-one (4a-g,7a-f). When arylaminomethyl( ethyl)pyrazolopyrimidine was treated with formaline (30%) solution in ethanol, underwent Mannich reaction to afford imidazopyrazolopyrimidines (5a-e) and pyrazolopyrimidopyrimidines (8a-e). Chloromethylpyrimidine derivative 3 was converted into the corresponding mercaptomethylpyrazolopyrimidene 9, Which cyclized using bromomalononitrile or phenacyl bromide into pyrazolopyrimidothiazine 11,12.