Efficient synthesis of pyrido[2,3-<i>d</i>]pyrimidine-7-carboxylic acids catalyzed by a TiO<sub>2</sub>/SiO<sub>2</sub> nanocomposite in aqueous media at room temperature
作者:Sepehr Sadegh-Samiei、Shahrzad Abdolmohammadi
DOI:10.1515/znb-2018-0076
日期:2018.9.25
Abstract A novel and efficientsynthesis of eight 5-aryl-1,3-dimethyl-2,4-dioxo-1,2,3,4,5,8-hexahydropyrido[2,3-d]pyrimidine-7-carboxylic acids using a TiO2/SiO2 nanocomposite with a molar ratio of 1:1 as a recyclable heterogeneous catalyst is described. The desired products, five of which are new, are formed in short reaction times (2–3 h) with high to excellent yields (94%–98%) under very moderate
TiO<sub>2</sub>
-SiO<sub>2</sub>
nanocomposite-promoted efficient cyclocondensation reaction of arylmethylidenepyruvic acids with dimedone in aqueous media
作者:Sepehr Sadegh-Samiei、Shahrzad Abdolmohammadi
DOI:10.1002/jccs.201800057
日期:2018.10
8‐hexahydro‐2‐quinolinecarboxylic acids through a condensation reaction of arylmethylidenepyruvic acids with ammonium acetate and dimedone using a catalytic amount of TiO2–SiO2 nanocomposite (15 mol%) at room temperature in aqueous media. The principal advantage of this procedure is the relatively high yields (94–98%) with short reaction times (2 hr), under mild reaction conditions and with low environmental impact
Heteroannulation of 2‐amino‐6‐thioxouracil: A new access for the synthesis of fused pyrimidine derivatives
作者:Hassan A. El‐Sayed、Mohamed G. Assy、Weam M. Mahmoud、Aly A. El‐Sheakh、Hesham A. Morsy
DOI:10.1002/jhet.3825
日期:2020.2
2‐amino‐6‐thioxouracil to newfusedpyrimidine scaffolds is described, where pyrimidine 1 undergoes cyclocondensation with pyruvic acid derivative 2 and ninhydrin (6) to furnish thiopyranopyrimidine 5 and thienopyrimidine 8, respectively. Alkylation of aminopyrimidine 1 with benzyl chloride consumed two moles to form S‐ and N‐alkylated product 9. Subjecting compound 9 to aminolysis with aniline derivatives resulted
在当前的工作中,描述了2-氨基-6-硫杂嘧啶与新的稠合嘧啶支架的异环化反应,其中嘧啶1与丙酮酸衍生物2和茚三酮(6)进行环缩合,分别提供硫代吡喃并嘧啶5和噻吩并嘧啶8。氨基嘧啶1与苄基氯的烷基化消耗了2摩尔,形成S-和N-烷基化产物9。用苯胺衍生物对化合物9进行氨解,得到4-氨基嘧啶10a,b通过Dimorth重排。此外,将环烯胺10a,b添加到茚三酮和苯甲酰基异硫氰酸酯中,得到嘧啶衍生物12a,b和14。最后,在极化体系2或18中添加10a,b的新生代碳,可获得中等至良好收率的吡啶并[2,3- d ]嘧啶17和21a-d。