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
ZnO Nanoparticles-Catalyzed Cyclocondensation Reaction of Arylmethylidenepyruvic Acids with 6-Aminouracils
作者:Shahrzad Abdolmohammadi
DOI:10.2174/1386207311316010005
日期:2013.1.1
A new, efficient, and solvent-free cyclocondensation reaction of arylmethylidenepyruvic acids with 6-
aminouracils is presented that uses a catalytic amount of ZnO nanoparticles (ZnO Nps) as a recyclable catalyst at 70 °C.
This protocol has the advantages of high yields (91-98%), easy work-up, very short reaction time (2 h), and using
environmentally friendly procedure.
An Efficient Synthesis of Novel Hexahydropyrido[2,3-<i>d</i>]pyrimidine Derivatives from (Arylmethylidene)pyruvic Acids (=(3<i>E</i>)-4-Aryl-2-oxobut-3-enoic Acids) in Aqueous Media
Abstractmagnified imageA series of new hexahydropyrido[2,3‐d]pyrimidine derivatives 3 were synthesized by the cyclocondensation reaction of (arylmethylidene)pyruvic acids (=(3E)‐4‐aryl‐2‐oxobut‐3‐enoic acids) 1 and 6‐aminouracils (=6‐aminopyrimidine‐2,4(1H,3H)‐diones) 2 in H2O under reflux conditions (Scheme 1, Table). This novel protocol has the advantages of facility, of easy workup, of high yields, and of an environmentally benign procedure. The structures of compounds 3a–3f were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS). A plausible mechanism for the reaction is proposed (Scheme 2).