Regioselective reactions of ethyl (4,5-dihydrofuran-3-yl)-2-oxoacetate and ethyl 2-(3,4-dihydro-2 H-pyran-6-yl)-2-oxoacetate with 1-unsubstituted aminoazoles

摘要

The reactions of ethyl (4,5-dihydrofuran-3-yl)-2-oxo-acetate and ethyl 2-(3,4-dihydro-2H-pyran-6-yl)-2-oxoacetate, as 1,3-bielectrophiles, with N-unsubstituted 5-aminoazoles, as N-C-N-binucleophiles, are the subject of this work. Regioselective heterocyclizations of ethyl 2-(3,4-dihydro-2H-pyran-6-yl)- 2-oxoacetate lead to 3-hydroxypropyl-7-ethoxycarbonyl substituted pyrazolo[1,5-a]pyrimidines and triazolo[1,5-a]pyrimidines whilst the corresponding reactions of ethyl (4,5-dihydrofuran-3-yl)-2-oxoacetate result in the formation of oxodihydropyrano[4,3-e] annulated products.