scholarly journals pH-Dependent Selective Colorimetric Detection of Proline and Hydroxyproline with Meldrum’s Acid-Furfural Conjugate

Chemosensors ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 343
Author(s):  
Lisa Zeußel ◽  
Carlos Aziz ◽  
Andreas Schober ◽  
Sukhdeep Singh

Activated 2-furfural gives intense color formation when reacted with amines, due to a ring opening reaction cascade that furnishes a conjugated molecular system. Unique colorimetric characteristic of this reaction makes it an interesting candidate for developing chemosensors operating in visible range. Among many activated 2-furfural derivatives, Meldrum’s acid furfural conjugate (MAFC) recently gained significant interest as colorimetric chemosensor. MAFC has been explored as selective chemosensor for detecting amines in solution, secondary amines on polymer surfaces and even nitrogen rich amino acids (AA) in aqueous solution. In this work, the pH dependency of MAFC-AA reaction is explored. It was found that proline gives an exceptionally fast colored reaction at pH 11, whereas at other pHs, no naked eye color product formation was observed. The reaction sequence including ring opening reaction upon nucleophilic addition of cyclic amine of proline resulting in a conjugated triene was confirmed by NMR titrations. The highly pH dependent reaction can e.g., potentially be used to detect proline presence in biological samples. An even more intense color formation takes place in the reaction of natural proline derivative 4-hydroxyproline. The detection limit of proline and 4-hydroxyproline with MAFC solution was found to be 11 µM and 6 µM respectively.

2000 ◽  
Vol 65 (12) ◽  
pp. 1911-1938 ◽  
Author(s):  
Peter Šafář ◽  
František Považanec ◽  
Naďa Prónayová ◽  
Peter Baran ◽  
Guido Kickelbick ◽  
...  

5-[(2-Furyl)methylidene]-2,2-dimethyl-1,3-dioxane-4,6-dione (1a) treated with equimolar amount of pyrrolidine or hexahydroazepine afforded 5-(pyrrolidine)- (2a) or 5-[(hexahydro- azepine-1-yl)-2-hydroxypenta-2,4-dien-1-ylidene]-2,2-dimethyl-1,3-dioxane-4,6-dione (2d). Their treatment with hydrobromic acid led to cyclization and formation of stable 5-cyclopentenyl-4H-1,3-dioxine hydrobromides (3a, 3d). Under the same conditions 1a treated with morpholine or piperidine yielded a mixture of 2b, 3b and 2c, 3c, respectively. The corresponding 3-substituted furans 1b-1e gave only substituted 5-cyclopentenyl-4H-1,3-dioxines (3e-3i). The use of an excess amine in reaction with 1a yielded unexpectedly 5-(3,5-dihetaryl-cyclopent-2-en-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-diones (9a-9c) and 5-[5-hexahydroazepin-1-ium-1-ylidene-2-(hexahydroazepin-1-yl)cyclopent-1-en-1-yl]-2,2-dimethyl-4-oxo-4H-1,3-dioxin-6-olates (10).


ChemInform ◽  
2010 ◽  
Vol 32 (26) ◽  
pp. no-no
Author(s):  
Peter Safar ◽  
Frantisek Povazanec ◽  
Nada Pronayova ◽  
Peter Baran ◽  
Guido Kickelbick ◽  
...  

2018 ◽  
Author(s):  
Veejendra Yadav ◽  
Dasari L V K Prasad ◽  
Arpita Yadav ◽  
Maddali L N Rao

<p>The torquoselectivity of conrotatory ring opening of 3-carbomethoxycyclobutene is controlled by p<sub>C1C2</sub>→s*<sub>C3C4</sub> and s<sub>C3C4</sub>→p*<sub>CO</sub> interactions in the transition state in a 4-electron process as opposed to only s<sub>C3C4</sub>→p*<sub>CO</sub> interaction in an apparently 8-electron event in 3-carbomethoxy-1,2-benzocyclobutene. The ring opening of 3-carbomethoxy-1,2-benzocyclobutene is sufficiently endothermic. We therefore argue that the reverse ring closing reaction is faster than the forward ring opening reaction and, thus, it establishes an equilibrium between the two and subsequently allows formation of the more stable species <i>via</i> outward ring opening reaction. Application of this argument to 3-dimethylaminocarbonyl-1,2-benzocyclobutene explains the predominantly observed inward opening.</p>


2020 ◽  
Vol 23 (23) ◽  
pp. 2626-2634
Author(s):  
Saiedeh Kamalifar ◽  
Hamzeh Kiyani

: An efficient and facial one-pot synthesis of 4-aryl-3,4-dihydrobenzo[g]quinoline- 2,5,10(1H)-triones was developed for the first time. The process proceeded via the three-component cyclocondensation of 2-amino-1,4-naphthoquinone with Meldrum’s acid and substituted benzaldehydes under green conditions. The fused 3,4-dihydropyridin-2(1H)- one-ring naphthoquinones have been synthesized with good to high yields in refluxing ethanol as a green reaction medium. This protocol is simple and effective as well as does not involve the assistance of the catalyst, additive, or hazardous solvents.


2021 ◽  
Vol 2021 (3) ◽  
pp. 325-325
Author(s):  
Malcolm P. Huestis ◽  
Jean‐Philippe Leclerc ◽  
Robin Larouche‐Gauthier ◽  
Samuel Aubert‐Nicol ◽  
Arun Yadav ◽  
...  

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