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
The Pd(ii)-catalyzed pyridine-directed carbonylative cycloamidation of ketoimines has provided an efficient protocol for assembly of pyrido[1,2-a]pyrimidin-4-ones.
Metal free C-3 chalcogenation (sulfenylation and selenylation) of 4<i>H</i>-pyrido[1,2-<i>a</i>]pyrimidin-4-ones
作者:Prasanjit Ghosh、Gautam Chhetri、Sajal Das
DOI:10.1039/d1ra00834j
日期:——
An expeditious metal free C-3 chalcogenation of 4H-pyrido[1,2-a]pyrimidin-4-one has been devised to synthesize diversely orchestrated 3-ArS/ArSe derivatives in high yields (up to 95%). This operationally simple reaction proceeds under mild reaction conditions, can be executed in gram scale, and also highlights broad functional group tolerance. Preliminary experimental investigation suggests a radical
设计了 4 H -pyrido[1,2- a ]pyrimidin-4-one 的快速无金属 C-3 硫属化反应,以高产率(高达 95%)合成多种精心设计的 3-ArS/ArSe 衍生物。这种操作简单的反应在温和的反应条件下进行,可以以克级进行,并且还突出了广泛的官能团耐受性。初步实验研究表明了这些转变的根本机制途径。
Transition-metal-free lactamization of C(sp<sup>3</sup>)–H bonds with CO<sub>2</sub>: facile generation of pyrido[1,2-<i>a</i>]pyrimidin-4-ones
A novel carbonylation of C(sp3)–H bonds in pyridylamines with one atmosphere of CO2 is reported to synthesize important pyrimidinones in good yields. This transition-metal-free and redox-neutral process features the use of a nontoxic carbonyl source, broad substrate scope, good functional group tolerance, facile scalability and easy product derivatization.
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。