Metal and Solvent-Free Synthesis of 2<i>H</i>-Pyrido[1,2-<i>a</i>]pyrimidin-2-ones Catalyzed by Elemental Sulfur
作者:Thangavel Pavithra、E. Sankari Devi、Subbiah Nagarajan、Vellaisamy Sridharan、C. Uma Maheswari
DOI:10.1002/ejoc.201901356
日期:2019.10.31
method for the synthesis of 4‐methyl‐2H‐pyrido[1,2‐a]pyrimidin‐2‐onefrom β‐oxo esters and 2‐aminopyridine in the presence of sulfur was demonstrated. In this reaction, inexpensive and readily available starting materials and catalysts were employed. The advantages of this strategy are: (i) A neat, oxidant and metal free reaction. (ii) The reaction was tolerant to different β‐oxo esters and 2‐aminopyridines
展示了一种在硫存在下由β-氧代酯和2-氨基吡啶合成4-甲基-2 H-吡啶并[1,2 - a ]嘧啶-2-酮的简单有效的方法。在该反应中,使用廉价且容易获得的起始原料和催化剂。该策略的优点是:(i)纯净,无氧化剂和无金属的反应。(ii)该反应可耐受不同的β-氧代酯和2-氨基吡啶
The reactions of 2-aminothiazoles and 2-aminobenzothiazoles with propiolic acid and its esters
作者:D. W. Dunwell、D. Evans
DOI:10.1039/j39710002094
日期:——
The main products from the title reactions were 7H-thiazolo[3,2-a]pyrimidin-7-ones (IV) and 2H-pyrimido-[2,1-b]benzothiazol-2-ones (V). Treatment of some of these with primary and secondary aliphatic amines yielded 2-(β-aminoacryloyl)imino-Δ4-thiazolines (X) and the corresponding benzo-analogues (XI).
标题反应的主要产物是7 H-噻唑并[3,2 - a ]嘧啶-7-酮(IV)和2 H-嘧啶-[ 2,1- b ]苯并噻唑-2-酮(V)。其中一些的伯和仲脂族胺处理得到2-(β-aminoacryloyl)亚氨基Δ 4 -thiazolines(X)和相应的苯并类似物(XI)。
AL-JALLO H. N.; MUNIEM M. A., J. HETEROCYCL. CHEM., 1978, 15, NO 5, 849-853