Intramolecular and intermolecular diels-alder reactions of acylhydrazones derived from methacrolein and ethylacrolein
作者:Sylvia J. Allcock、Thomas L. Gilchrist、Stephen J. Shuttleworth、Frank D. King
DOI:10.1016/s0040-4020(01)96054-5
日期:1991.1
The intramolecular Diels-Alder reactions of hydrazones derived from methacrolein or ethylacrolein and terminally unsaturated N-acyl-N-methylhydrazines have been investigated. The hydrazones 7b and 7c derived from N-methyl-N-pent-4-enoylhydrazine 3b were found to undergo intramolecular [4 + 2] cycloaddition above 140 °C and the pyridopyridazines 12 were isolated. The corresponding hydrazones 8b and
已经研究了衍生自甲基丙烯醛或乙基丙烯醛的hydr与末端不饱和N-酰基-N-甲基肼的分子内Diels-Alder反应。发现衍生自N-甲基-N-戊-4-烯丙基肼3b的7b和7c在140℃以上进行分子内[4 + 2]环加成,并分离了吡啶并哒嗪12。相应的腙图8b和图8c从Ñ甲基ñ -戊-4- ynoylhydrazone 4A同样反应,并得到作为最终产物的吡啶13。反应的范围是有限的,如αβ-不饱和醛的其他几种末端不饱和的分子内环加成反应所表明的。然而,这些确实发生了N-苯基马来酰亚胺的分子间[4 + 2]环加成反应。甲基丙烯醛的其他氢化物15。包括苯甲酰hydr和苯,,也与N-苯基马来酰亚胺反应,通过可分离的二氢吡啶16生成吡啶14b。