| 摘要 |
1,230,289. Pyrazolo - (3,4 - d) - pyrimidines. ZELLSTOFFFABRIK WALDHOF. 28 March, 1969 [1 April, 1968], No. 16374/69. Heading C2C. Pyrazolo - (3,4 - d) - pyrimidines are prepared by reacting an α - cyano - α - formylacetic acid, or a function acid and/or aldehyde derivative thereof, which is an ester, nitrile, acid amide, enol - ether, enamine, acetal or mercaptal derivative thereof, with a hydrazine containing at least three H atoms linked to N atoms, and an acid amide or amidine at a temperature of over 150‹ C. The reaction may be performed in the presence of an inert diluent or solvent or in the melt of the acid amide. An alkali metal alcoholate catalyst may also be present. In the examples the compound 4 - hydroxy - pyrazolo- (3,4 - d) - pyrimidine is obtained by reacting ethyl ethoxymethylene-cyanacetate, formamide and hydrazine hydrate. The 4 - amino -, 1- methyl - 4,6 - dihydroxy -, 1 - phenyl - 4,6- dihydroxy-, and 4 - hydroxy - 6 - methyl - pyrazolo - (3,4 - d) pyrimidines are also prepared. Reference has been directed by the Comptroller to Specification 798,646. |
