Synthèse des 2-hydroxy-7-〚benzimidazol-2-yl〛-méthyl-5-méthylpyrazolo〚1,5-a〛pyrimidines à partir de la 4-hydroxy-6-méthylpyran-2-one

Abstract

Condensation of 3-amino-5-hydroxypyrazole 1 with triacetic acid lactone 2 in refluxed alcohols afforded 2-hydroxy-5,7-dimethylpyrazolo〚1,5-a〛pyrimidine 3 beside to 7-alkoxycarbonylmethyl-2-hydroxy-5- methylpyrazolo〚1,5-a〛pyrimidine 4. Action of hydrazine on compounds 4 yielded 7-hydrazinocarbonylmethyl-2-hydroxy-5-methylpyrazolo〚1,5-a〛pyrimidine 5. Condensation of o-phenylenediamines 6 with hydrazide 5 to melting reactants afforded 2-hydroxy-7-〚benzimidazol-2-yl〛methyl-5-methylpyrazolo〚1,5-a〛pyrimidines 7. Structures of the obtained products have been assigned by means of spectroscopic measurements.