Regioselective Reactions of Ethyl (4,5-Dihydrofuran-3-yl)-2-oxoacetate and Ethyl 2-(3,4-Dihydro-2H-pyran-6-yl)-2-oxoacetate with 1-Unsubstituted Aminoazoles
01 March 2012 (eFirst)
The reactions of ethyl (4,5-dihydrofuran-3-yl)-2-oxoacetate 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.
lactones - aminoazoles - heterocyclization - pyrazolo[1,5-a]pyrimidines - triazolo[1,5-a]pyrimidines