G 65 Goryaeva, M. V. Peculiarities of cyclization of ethyl 2-ethoxymethylene-3-oxo-3- (polyfluoroalkyl)propionates with 3-amino-5-hydroxypyrazole [Electronic resource] / M. V. Goryaeva, Ya. V. Burgart, V. I. Saloutin // Journal of Fluorine Chemistry. - 2013. - Vol.147. - P15-21 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): 3-AMINO-5-HYDROXYPYRAZOLE -- RECYCLIZATION -- PYRIDINES Аннотация: The reactions of ethyl 2-ethoxymethylene-3-oxo-3-(polyfluoroalkyl) propionates with 3-amino-5-hydroxypyrazole result in ethyl 2,7-dihydroxy-7- (polyfluoroalkyl)-4,7-dihydropyrazolo[1,5-a]pyrimidin-6-carboxylates under mild conditions. These products undergo recyclization in refluxing ethanol to form ethyl 3-hydroxy-4-(polyfluoroalkyl)-1H-pyrazolo[3,4-b]pyridin-5-carboxylates, whereas in refluxing glacial acetic acid they are dehydrated to ethyl 2-hydroxy-7-(polyfluoroalkyl)pyrazolo[1,5-a]pyrimidin-6-carboxylates. The non-fluorinated ethyl 2-ethoxymethylene-3-oxo esters in the reactions with 3-amino-5-hydroxypyrazole in ethanol (or glacial acetic acid) under reflux form only ethyl 2-hydroxy-7-phenyl(hydroxy)pyrazolo[1,5-a]pyrimidin-6-carboxylates \\\\Expert2\\NBO\\Journal of Fluorine Chemistry\\2013, v. 147, p.15.pdf |