采用简单的离子交换法制备了具有Keggin结构的铝交换钨磷酸盐(Al x H 3− x PW 12 O 40)。通过各种技术,如元素分析,XRD,FTIR,UV-vis,N 2-物理吸附,NH 3 -TPD和FTIR-吡啶吸附,对制备的杂多酸盐进行了表征。所有制备的催化剂都具有布朗斯台德和路易斯酸位点,但是随着铝含量的增加,表面积和路易斯酸位点增加。该催化剂已被用作非均相催化剂,以在温和的反应条件下合成吡啶并[1,2- a ]嘧啶。多种具有生物活性的吡啶基[1,2-通过使用由Al x H 3− x PW 12 O 40催化剂催化的简单,环保和高效的方法,可以以最高的收率(90%以上)获得a ]嘧啶。Al 3 PW 12 O 40催化剂显示出最高的活性,这是由于通过Al 3+离子完全交换H +离子将更多的路易斯酸位引入母体H 3 PW 12 O 40。
inexpensive, nontoxic manganese catalyst enabled unprecedented redox‐neutral carbonylative annulations under ambient pressure. The manganese catalyst outperformed all other typically used base and precious‐metal catalysts. The outstanding versatility of the manganese catalysis manifold was reflected by ample substrate scope, setting the stage for effective late‐stage manipulations under racemization‐free
heterocycles due to their wide range of bioactivities. An efficient silver-catalyzed intermolecular cyclization of 2-aminopyridines with various alkynoates has been developed. 2-Substituted 4H-pyrido[1,2-a]pyrimidin-4-ones containing a wide range of functional groups are synthesized in the standard conditions. This transformation is conducted under convenient conditions and affords products in good yields
嘧啶酮由于其广泛的生物活性而成为重要的含氮杂环之一。已经开发了有效的银催化的2-氨基吡啶与各种链烷酸酯的分子间环化。在标准条件下合成含有2-官能取代的4 H-吡啶并[1,2 - a ]嘧啶-4-酮。该转化是在方便的条件下进行的,并以高收率提供产物。
Synthesis of some substituted pyrido[1,2-<i>a</i>]pyrimidin-4-ones and 1,8-naphthyridines
作者:Pier Luigi Ferrarini、Claudio Mori、Oreste Livi、Giuliana Biagi、Anna Maria Marini
DOI:10.1002/jhet.5570200442
日期:1983.7
The substituted 4H-pyrido[1, 2-a]pyrimidin-4-ones (I) were obtained by the condensation of substituted 2-aminopyridines with δ-ketocarboxylic esters in PPA. Some of the derivatives I were transformed into the corresponding 1, 8-naphthyridines II and III.
通过将取代的2-氨基吡啶与δ-酮羧酸酯在PPA中缩合,得到取代的4 H-吡啶并[1,2 - a ]嘧啶-4-酮(I)。一些衍生物I被转化为相应的1、8-萘啶II和III。
Practical synthesis of 4H-pyrido[1, 2-a]pyrimidin-4-ones using ethylene glycol as a promoting solvent
作者:Mustafa Hussain、Jianhui Liu
DOI:10.1016/j.tetlet.2020.152269
日期:2020.9
A simple and useful protocol leading to different 4H-pyrido[1, 2-a] pyrimidin-4-ones have been established by cyclization of various 2-amino pyridines with β-oxo ester or alkynoate. The use of ethylene glycol was demonstrated to facilitate this condensation. This reaction proceeds by nontoxic, cheap, environment friendliness and biodegradable solvent at the normal green atmospheric condition in the
Catalyst‐ and Oxidant‐Free Electrochemical Regioselective Halogenation and Trifluoromethylation of 4<i>H</i>‐Pyrido[1,2‐<i>a</i>]pyrimidin‐4‐ones
作者:Meiyun Su、Lina Guo、Peiyu Mao、Meng Xiao、Wenjie Liu、Shaohua Wang
DOI:10.1002/ejoc.202300268
日期:2023.8
halogenation and trifluoromethylation of 4H-pyrido[1,2-a]pyrimidin-4-ones with cheap and commercially available sodium salts have been developed under external oxidant-free conditions. The reaction shows broad scope of substrates, high regioselectivity, and good functional group compatibility. Importantly, the electrosynthesis of 4H-pyrido[1,2-a]pyrimidin-4-ones represents a green and advantageous alternative
已开发出在无外部氧化剂的条件下用廉价且市售的钠盐进行 4 H-吡啶并[1,2- a ]嘧啶-4-酮的无催化剂电化学卤化和三氟甲基化。该反应显示出底物范围广、区域选择性高、官能团相容性好。重要的是,4 H-吡啶并[1,2- a ]嘧啶-4-酮的电合成代表了传统合成方法的绿色且有利的替代方法。