Smart coacervate catalysis: robotic optimization of Knoevenagel reaction networks.

Multimodal Inclusion Complexes Between Barbiturates and 2‐Hydroxypropyl‐β‐Cyclodextrin in Aqueous Solution: Isothermal Titration Microcalorimetry, 13C NMR Spectrometry, and Molecular Dynamics Simulation

Constructing ultra-stable photothermal plastics assisted by carbon dots with photocaged reactivity

New interpolyelectrolyte complexes (IPECs) between oppositely charged Eudragit® EPO and Eudragit® L100 were investigated with a view to the development of oral controlled drug delivery systems (DDS). Structural features of the samples were evaluated by modulated-temperature differential scanning calorimetry (MTDSC). The results confirmed that all IPECs were chemically homogeneous and were characterized by only one glass-transition temperature. Evaluation of the diffusion-transport properties of the investigated IPECs revealed the basic mechanisms responsible for the controlled delivery of drugs with different physicochemical properties. The results showed that the synthesized IPECs have great potential to be used as pH-sensitive oral controlled DDS.

Introduction. One of the well-known requirements for buccal drug delivery systems is the demonstration of mucoadhesive properties of the carrier, ensuring retention on the mucosa for a long time with the gradual release of the included drug. It should be noted that one of the advantages of buccal systems compared with oral ones is the absence of the «first pass effect» through the liver.Aim. To carry out a physicochemical and pharmaceutical research of the interpolyelectrolyte complex (IPEC), obtained on the basis of pharmaceutically acceptable polymers – Eudragit® EPO and Noveon® AA-1, in comparison with the physical mixture and individual polymers, as a mucoadhesive delivery system of metronidazole for the treatment of periodontal diseases.Materials and methods. Obtained on the basis of a pair of pharmaceutical polymers (Eudragit® EPO and Noveon® AA-1), two IPEC samples were characterized by elemental analysis, FTIR spectroscopy, and modulated temperature differential scanning calorimetry (mDSC) in comparison with individual polymers and their physical mixtures. The study of swelling ability, bioadhesion and release was carried out in a medium simulating artificial salivary fluid (pH 7.0) at a temperature of 37 ± 0.1 °C. Mucoadhesion of polymer samples and IPEC was studied using a TA.XTplus texture analyzer (Stable Micro Systems, UK). The release of metronidazole (MD) from matrices based on the developed IPEC was studied on a CE 7Smart USP 4 apparatus (Sotax, Switzerland) using the Flow Trough Cell method at a speed a flow of 20 ml/min in an open cycle within 5 hours. The amount of released MD was estimated by UV spectrophotometry on a Lambda 25 instrument (PerkinElmer, USA) at a wavelength of 319 nm.Results and discussion. As a result of studies on the physicochemical and pharmaceutical properties, there was selected the optimal composition of a polycomplex carrier (IPEC 2) based on Eudragit® EPO and Noveon® AA-1, which is characterized by the required bioadhesive properties and the ability of providing controlled release of drug from the tablet matrix (with weight ratio MD/IPEC-2 1:0.5) in conditions mimicking oral cavity environment, which provides the necessary mode of buccal delivery of metronidazole in accordance with Fick's law of diffusion.Conclusion. IPEC 2 is a perspective for use as carrier for buccal controlled delivery of metronidazole.

Background: In this study, a heterogeneous catalyst containing MIL-101(Cr) functionalized TEDA-BAIL was used to carry out an efficient four-component reaction between aromatic aldehydes, barbituric acid, dimedone, and aryl amines, resulting in the synthesis of a new class of pyrimido[ 4,5-b]quinolinetrione derivatives. Methods: Pyrimido[4,5-b]quinolinetrione derivatives were synthesized through a one-pot fourcomponent reaction between aromatic aldehydes, barbituric acid, dimedone, and aryl amines, in the presence of triethylenediamine-based ionic liquid@MIL-101(Cr) composite as a catalyst under reflux conditions. The TEDA-BAIL@MIL-101(Cr), which is a recyclable catalyst, was fully characterized by Fourier transform infrared spectrophotometry (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) and Transmission electron microscopy (TEM). Results: Four-component synthesis of pyrimido[4,5-b]quinolinetriones was catalyzed by TEDABAIL@ MIL-101(Cr) with aromatic aldehydes, barbituric acid, dimedone, and aryl amines under reflux conditions. The obtained experimental results revealed that the employed synthesis approach is a simple method that offers several advantages, including sustainability, facile separation from the reaction medium, and reusability of the catalyst after six consecutive runs without loss of activity. Conclusion: The presented method is an efficient synthesis route for the synthesis of pyrimido[4,5- b]quinolinetriones in the presence of TEDA-BAIL@MIL-101(Cr) under reflux conditions. This procedure provides multiple advantages, such as ease of execution, high yield, clean reaction conditions, shorter reaction time, and catalyst sustainability.

With a view to the development of oral controlled drug delivery systems (DDS), new interpolyelectrolyte complexes (IPECs) between oppositely charged types of Eudragit ЕРО and Eudragit L100 have been investigated. Structural features of the samples were evaluated by modulated-temperature differential scanning calorimetry (MTDSC). The obtained data confirm that all polycomplexes are chemically homogenous and characterized by only one glass transition temperature. Evaluation of the diffusion transport properties of investigated IPECs revealed basic mechanisms responsible for the controlled delivery of drugs with different physicochemical properties. The results show that the synthesized IPECs have great potential to be used as pH-sensitive oral controlled DDS.

Bentonite-titana composite was prepared and characterized by XRD, FT-IR and SEM. Results indicate that TiO2 particles have been supported on the bentonite layers and a delaminated structure is formed. Then the bentonitetitana composite as a mild, eco-friendly, non-toxic an efficient heterogeneous catalyst have been used for synthesis of benzopyran derivatives from the three-component condensation reaction of dimedone or barbituric acid, malonoitrile, and aromatic aldehydes under solvent free conditions in good to excellent yield and short reaction times. Keywords: Bentonite-titana composite, benzopyran, dimedone, malonoitrile, barbituric acid, pyrano[2, 3-d]pyrimidine.

magnified image Condensation of cyclohexane‐1,3‐dione/barbituric acid, thiourea/urea, and aromatic aldehyde in the mole ratio of 1:1:3 in solventless reaction in presence of NiCl2/KI afforded 1,5‐diaryl‐3‐thioxo‐2,4‐ diazaspiro[5.5]undecane‐7,11‐dione/1,5‐diaryl‐2,4‐diazaspiro[5.5]undecane‐3,7,11‐trione analogues and 7,11‐diaryl‐9‐thioxo‐2,4,8,10‐tetraazaspiro[5.5]undecane‐1,3,5,‐trione/7,11‐diaryl‐2,4,8,10‐tetraazaspiro[5.5] undecane‐1,3,5,9‐tetraone analogues, respectively. The similar condensation of cyclohexane‐1,3‐dione/cyclohexanone, thiourea/urea, and aromatic aldehyde/heteroaromatic aldehyde in the mole ratio of 1:1:1 in refluxing methanol afforded 4‐aryl/heteroaryl‐2‐thioxo‐1,2,3,4,5,6,7,8‐octahydroquinazolin‐5‐one, 4‐aryl/heteroaryl‐1,2,3,4,5,6,7,8‐octahydroquinazoline‐2,5‐dione analogues and 4‐aryl/heteroaryl‐1,2,3,4,5, 6,7,8‐octahydroquinazoline‐2‐thione, 4‐aryl/heteroaryl‐1,2,3,4,5,6,7,8‐octahydroquinazolin‐2‐one analogues, respectively. Condensation of heterocyclic active methylene compound, barbituric acid, thiourea/urea, and aromatic aldehydes under similar set of conditions in 1:1:1 mole ratio was carried which afforded 5‐aryl‐7‐thioxo‐1,2,3,4,5,6,7,8‐octahydropyrimido[4,5‐d]pyrimidine‐2,4‐dione/5‐aryl‐1,2,3,4,5, 6,7,8‐octahydropyrimido[4,5‐d]pyrimidine‐2,4,7‐trione analogues. Similar condensation of an active methine compound, 2‐acetylcyclohexanone, thiourea/urea, and aromatic aldehydes in the mole ratio of 1:1:1 produced 5‐aryl‐1‐methyl‐3‐thioxo‐2,4‐diazaspiro[5.5]undec‐1‐en‐7‐one/5‐aryl‐1‐methyl‐2, 4‐diazaspiro[5.5]undec‐1‐ene‐3, 7‐dione analogues, the spiro compounds of entirely different kind. All these identifications and characterizations have been based on the elemental analysis and spectral data. J. Heterocyclic Chem., (2010).

In situ forming hydrogel of natural polysaccharides through Schiff base reaction for soft tissue adhesive and hemostasis

Polysaccharides-based multiparticulated interpolyelectrolyte complexes for controlled benznidazole release

We report synthesis of triphenyl(propyl-3-hydrogen sulfate)phosphonium bromide ([TPPHSP]Br) as a reusable green Bronsted-acidic ionic liquid catalyst and its application for synthesis of 5-arylidene barbituric acids and pyrano[2,3-d]pyrimidine derivatives by condensation reaction between aromatic aldehydes and barbituric acid or aromatic aldehydes, malononitrile, and barbituric acid in EtOH–H2O in reflux condition with good to excellent yield. The [TPPHSP]Br IL catalyst was characterized by Fourier-transform infrared (FT-IR) spectroscopy, 1H and 13C nuclear magnetic resonance (NMR), and thermogravimetric (TG) analysis and showed good catalytic activity and reusability.

New fused heterocyclic compounds of the 8,15,17-triaza-d-homogonane series have been obtained by ternary condensation of cyclic azomethines (1-methyl-3,4-dihydroisoquinolines) with aromatic aldehydes and barbituric acid in DMF.

Several aromatic and α,β‐conjugated aromatic aldehydes were condensed with barbituric acid in methanol solution in the absence of acid or base as a catalyst, affording 5‐ylidenebarbituric acid derivatives in almost quantitative yields.

Knoevenagel condensation of α,β-unsaturated aromatic aldehydes with barbituric acid under non-catalytic and solvent-free conditions

ChemInformVolume 41, Issue 36 Heterocyclic Compounds ChemInform Abstract: N,N-Dimethylformamide-Promoted Reaction of Isocyanides and Barbituric Acids: An Easy Synthesis of 5-[(Alkyl or Arylamino)methylene]barbituric Acids. Mohammad Bagher Teimouri, Mohammad Bagher Teimouri Fac. Chem., Islamic Azad Univ., Omidiyeh, IranSearch for more papers by this authorAhmad Tayyebi, Ahmad Tayyebi Fac. Chem., Islamic Azad Univ., Omidiyeh, IranSearch for more papers by this author Mohammad Bagher Teimouri, Mohammad Bagher Teimouri Fac. Chem., Islamic Azad Univ., Omidiyeh, IranSearch for more papers by this authorAhmad Tayyebi, Ahmad Tayyebi Fac. Chem., Islamic Azad Univ., Omidiyeh, IranSearch for more papers by this author First published: 12 August 2010 https://doi.org/10.1002/chin.201036166Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume41, Issue36September 7, 2010 RelatedInformation