Visible Light Mediated, Photocatalyst‐Free Condensation of Barbituric Acid with Carbonyl Compounds

Abstract

An economical and efficient method has been developed for the production of dibarbiturates of oxindole and arylidene barbituric acid derivatives via condensation of of isatin/aryl aldehyde with barbituric acid, through irradiation of visible light. Under the similar conditions 2 molecules of barbituric acid react with 1 molecule of isatin while only 1 molecule of barbituric acid reacts with 1 molecule of aldehyde. This transformation involves catalyst free pathway for the formation of desired products under mild reaction conditions. Metal free reaction conditions, high yield of products along with the absence of side‐products are additional green features of this protocol.

Visible-Light-Initiated Oxidative Coupling of Indole and Active Methylene Compounds Using Eosin Y as a Photocatalyst

“…The following plausible mechanism is proposed based on preceding reports 36,37 and the control experiments (Scheme 5). Upon exposure to visible light, excited Eosin Y (EY*) is formed from Eosin Y (EY).…”

“…All rights reserved. The following plausible mechanism was proposed based on the preceding reports 36,37 and control The reaction occurs efficiently under milder conditions and virtually in assessable yield of the desired coupling products. This approach displays outstanding functional group compatibility with both electron-donating and electron-withdrawing indole.…”

A green synthesis of pyrimido[4,5-b]quinolines and pyrido[2,3-d]pyrimidines via a mechanochemical approach

“…As part of our ongoing research work to develop environmentally friendly methods for organic synthesis, 48–55 herein, we report for the first time our result for a nearly green synthesis protocol for pyrimido[4,5- b ]quinolines and pyrimido[2,3- d ]pyrimidines via a one-pot multicomponent reaction of aromatic aldehyde, 6-aminouracil, and 1,3-diketo compounds under ball-milling conditions within a brief reaction time (Scheme 1(III a and b)).…”

Microwave-assisted synthetic method of novel Bi2O3 nanostructure and its application as a high-performance nano-catalyst in preparing benzylidene barbituric acid derivatives

“…Although some researchers have reported this reaction with the use of no catalyst (Vieira et al, 2011;Figueroa-Villar and Vieira. 2013;Vieira et al, 2015), irradiation of visible light (Kumari et al, 2021), the following catalysts are used and introduced in this regard: [DABCO](SO 3 H) 2 Cl 2 (Shirini et al, 2015), [DABCO] (SO 3 H) 2 (HSO 4 ) 2 (Seyyedi et al, 2016), p-nanoporous MMT-HClO 4 (Mashhadinezhad et al, 2018), dodecylbenzenesulfonic acid (DBSA) (Hosseini et al, 2016), FeCl 3 .6H 2 O (Kefayati et al, 2014), ethylammonium nitrate (Hu et al, 2004), silico-tungstic acid (Li and Sun, 2009), amino-sulfonic acid (Li et al, 2006), NaOH/fly ash (Gadekar and Lande, 2012), sodium p-toluene sulfonate (NaPTSA) (Kamble et al, 2010), CoFe 2 O 4 -NPs (Rajput and Karur, 2013), non-catalyst/infrared irradiation (Alarreca et al, 2000), BF 3 / nano γ-Al 2 O 3 (Mirjalili et al, 2015), succinimidinium N-sulfonic acid hydrogen sulfate ([SuSA-H]HSO 4 ) (Abedini et al, 2016), basic alumina (KhalafInezhad and Hashemi, 2001), Verjuice (Safari et al, 2019), sulfonic acid functionalized nanoporous silica (SBA-Pr-SO 3 H) (Shirini et al, 2015), copper oxide nanoparticles (CuO-NPs) (Dighore et al, 2014), aminosulfonic acid (NH 2 SO 3 H) (Li et al, 2006), 2amino-3-(4-hydroxyphenyl) propanoic acid (L-tyrosine) (Thirupathi et al, 2013), CoFe 2 O 4 nanoparticles (Rajput and Kaur, 2013), sodium acetate (CH 3 COONa) (Uttam, 2016), 1-nbutyl-3-methylimmidazolium tetrafluoroborate ([bmim]BF 4 ) (Wang et al, 2005), polyvinyl pyrrolidone stabilized nickel nanoparticles (PVP-Ni-NPs) (Khurana and Vij, 2010), cetyltrimethyl ammonium bromide (CTMAB) (Ren et al, 2002), ethyl ammonium nitrate (EAN)…”