cis-Nitromethylene neonicotinoids as new nicotinic family: Synthesis, structural diversity, and insecticidal evaluation of hexahydroimidazo[1,2-α]pyridine
摘要:
A series of neonicotinoids analogues of hexahydroimidazo[1,2-alpha]pyridine were modified at 5-, 6-, and 7-positions, and their insecticidal activities were evaluated. Introducing a methyl or ethyl at 7-position increased the insecticidal activities, while other substituents decreased activities. When alkyl substituents were introduced to 7-position, the insecticidal activities against Pea aphids decreased in the order methyl (7a) > ethyl (7b) > n-butyl (7e) > phenyl (7f) > n-propyl (7c) > iso-propyl (7d), p-NO2-phenyl (7g). Modifications at 5-, 6- or both at 6- and 7-positions with methyl or ethyl were unfavorable to activities. Interestingly, introducing methyl to 7-position not only increased insecticidal activities against pea aphids, but also show higher insecticidal activities than imidacloprid against imidacloprid-resistant brown planthopper. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.
Organocatalytic Michael addition of 2-nitro methylene imidazolidines to α,β-unsaturated aldehydes: concise synthesis of chiral insecticide Paichongding
作者:Yanpeng Lou、Yin Xu、Zhuo Chai、Xusheng Shao、Gang Zhao、Zhong Li
DOI:10.1016/j.tet.2015.07.056
日期:2015.9
An organocatalyticMichael reaction of 2-nitro methylene imidazolidines to α,β-unsaturatedaldehydes followed by acetal-amination affords hexahydroimidazo[1,2-a]pyridines in high yields and with moderate to excellent enantioselectivity. The utility of the reaction was illustrated by a one-step transformation to Paichongding, an insecticide of the neonicotinoid family.
2-硝基亚甲基咪唑烷对α,β-不饱和醛的有机催化迈克尔反应,然后进行乙缩醛胺化,可高产率地得到六氢咪唑并[1,2- a ]吡啶,并且具有中等至优异的对映选择性。通过一步转化为新烟碱类杀虫剂Paichongding可以说明该反应的实用性。