Treatment of 1,4-diketones with liquidammonia gives high yields of isolable 2-hydroxy-3,4-dihydro-2H-pyrrole intermediates. These intermediates, which do not appear to have been observed previously in the Paal-Knorrsynthesis with ammonia, have been fully characterized by i.r. and 1H and 13C n.m.r. spectroscopy; in most cases they decompose quantitatively into 1H-pyrroles on standing. The intermediate from
用液氨处理1,4-二酮可获得高产率的可分离的2-羟基-3,4-二氢-2 H-吡咯中间体。这些中间体,以前似乎没有在Paal-Knorr与氨的合成中观察到,已通过ir,1 H和13 C nmr光谱进行了全面表征。在大多数情况下,它们在站立时会定量分解为1 H-吡咯。来自己烷-2,4-二酮的中间体也可以使用浓氨水制备。