A simple synthesis of 4-(2-aminoethyl)-5-hydroxy-1H-pyrazoles
作者:David Kralj、Uroš Grošelj、Anton Meden、Georg Dahmann、Branko Stanovnik、Jurij Svete
DOI:10.1016/j.tet.2007.07.052
日期:2007.11
A simple four-step synthesis of 4-(2-aminoethyl)-5-hydroxy-1H-pyrazoles 8 (or their 1H-pyrazol-3(2H)-one tautomers 8′) as the pyrazole analogues of histamine was developed. First, enamino lactam 3 was prepared as the key intermediate in two steps from 2-pyrrolidinone (1). Next, acid-catalysed ‘ring switching’ transformations of 3 with monosubstituted hydrazines 4 gave N-[(1-substituted 5-hydroxy-1