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An Expeditious Synthesis of N-substituted Pyrroles via Microwave-Induced Iodine-Catalyzed Reactions under Solventless Conditions  [PDF]
Debasish Bandyopadhyay,Sanghamitra Mukherjee,Bimal K. Banik
Molecules , 2010, DOI: 10.3390/molecules15042520
Abstract: An expeditious synthesis of N-substituted pyrroles has been developed by reacting 2,5-dimethoxy tetrahydrofuran and several amines using a microwave-induced molecular iodine-catalyzed reaction under solventless conditions.
Synthesis and Fungicidal Activity of Novel 2,3-Disubstituted-1,3-benzoxazines  [PDF]
Zilong Tang,Zhonghua Zhu,Zanwen Xia,Hanwen Liu,Jinwen Chen,Wenjing Xiao,Xiaoming Ou
Molecules , 2012, DOI: 10.3390/molecules17078174
Abstract: A series of new 2,3-disubstituted-3,4-dihydro-2H-1,3-benzoxazines were prepared in moderate to excellent yields by aza-acetalizations of aromatic aldehydes with 2-(N-substituted aminomethyl)phenols in the presence of TMSCl. Their structures were confirmed by IR, 1H-NMR, 13C-NMR, MS and elemental analysis. The fungicidal activities of the target compounds were preliminarily evaluated, and some compounds exhibited good activity against Rhizoctonia solani.
Solventless Lactam Synthesis by Intramolecular Cyclizations of α-Iminoester Derivatives under Microwave Irradiation  [PDF]
Fatima-Zohra Zradni,Jack Hamelin,Aicha Derdour
Molecules , 2007, DOI: 10.3390/12030439
Abstract: We have previously reported a new synthesis of amides from esters and amines under microwave irradiation, offering much higher yields than those achieved with conventional heating [1]. We have now extended these studies to the ring closure of neat iminoesters I2, I3 and I4-I6 to give five- and six-membered ring lactams L5, L6 and larger lactams L7-L9 (where I means imine and L means lactam), respectively, under both classical heating conditions and microwave irradiation.
Synthesis Characterization and Antibacterial, Antifungal Activity of N-(Benzyl Carbamoyl or Carbamothioyl)-2-hydroxy Substituted Benzamide and 2-Benzyl Amino-Substituted Benzoxazines  [PDF]
Tyson Belz,Saleh Ihmaid,Jasim Al-Rawi,Steve Petrovski
International Journal of Medicinal Chemistry , 2013, DOI: 10.1155/2013/436397
Abstract: New N-(benzyl carbamothioyl)-2-hydroxy substituted benzamides 13, 20, and 21 were synthesized using sodium bicarbonate and benzyl amine with 2-thioxo-substituted-1,3-benzoxazines 6, 10a, b, 11c, and 12a–n. The 2-thioxo-substituted-1,3-oxazines 6, 10a-b, 11d 12a–n, and 26 were converted to the corresponding 2-methylthio-substituted-1,3-oxazines 14a–l and 24 which were then converted to 2-benzyl amino-substituted-benzoxazines 15a–i by refluxing with benzylamine. Products 15a, b, e, f, and g were also synthesized by boiling the corresponding N-(benzyl carbamothioyl)-2-hydroxy substituted benzamides 13a, b, f, l, and m in acetic acid. 2-Oxo-substituted-1,3-benzoxazines 22 and 25 were prepared by treating the corresponding 2-methylthio-substituted-1,3-oxazines 14 and 24 with dilute HCl. The N-(benzyl carbamoyl)-2-hydroxy substituted benzamide 23 was synthesized from the reaction of 2-oxo-substituted-1,3-benzoxazine 22 with benzylamine. The new products were characterized using IR, 1H, and 13C NMR in addition to microanalysis. Selected compounds were tested in vitro for antibacterial and antifungi activity and the most active compounds were found to be the 4-(substituted-benzylamino)-2-hydroxy benzoic acids 9a and d (M. chlorophenolicum, MIC 50 and 25?μgm?L?1, resp.), N1, N3-bis (benzyl carbamothioyl)-4,6-dihydroxy-substituted phthalamides 20a and 20c (B. subtilis MIC 12.5, 50?μgm?L?1, resp.) and 21 (M. chlorophenolicum, MIC 50?μgm?L?1). 1. Introduction The search for new antibacterial compounds is a challenging task as bacteria are continuously developing resistance to antimicrobial compounds; however, infections due to such bacterial strains are infrequent although potentially fatal [1–3]. This ongoing problem has resulted in the search for newer, more effective antibacterial compounds [1–3]. Urea, thiourea 3 (X=O or S), and benzo-1,3-oxazine compounds 5 and 6 (Scheme 1) have been shown to possess antibacterial and antifungal properties [4–11]. The benzyl thiourea analogue 3 has been reported to show activity against Gram-positive bacteria [12]. Scheme 1: Previous synthesis of urea or thiourea 3 (X=O or S) and 2-amino benzo1,3-oxazine 5. The N-benzoyl-2-hydroxybenzamides [13] are important pharmacophores for antibacterial activity in which the 2-hydroxy group (hydrogen bonding donor) contributes to the activity, the imide linker (preferred) or urea linker retains activity and free NH is required for high activity. The Topliss method [14] was used in the optimization of salicylic acid derivatives for potential use as antibacterial agents. The employment and
Comparative Study of Regioselective Synthesis of β-Aminoalcohols under Solventless Conditions Catalyzed by Sulfated Zirconia and SZ/MCM-41  [PDF]
Guillermo Negrón-Silva,C. Xochitl Hernández-Reyes,Deyanira Angeles-Beltrán,Leticia Lomas-Romero,Eduardo González-Zamora,Juan Méndez-Vivar
Molecules , 2007, DOI: 10.3390/12112515
Abstract: Sulfated zirconia and SZ/MCM-41 were used as catalysts for the synthesis of β-aminoalcohols via epoxide aminolysis. Sulfated zirconia was prepared by sol-gel andSZ/MCM-41 was obtained by impregnation. Solid catalysts were characterized by XRD,SEM-EDS, UV-Vis, FT-IR pyridine desorption and Nitrogen physisorption. Both acidmaterials were useful as catalysts, even when they were recycled several times. The β-aminoalcohols were characterized by FT-IR, 1H- and 13C-NMR and GC-MS.
Facile Solventless Synthesis of a Nylon-6,6/Silver Nanoparticles Composite and Its XPS Study  [PDF]
Raúl A. Morales-Luckie,Víctor Sánchez-Mendieta,Oscar Olea-Mejia,Alfredo R. Vilchis-Nestor,Gustavo López-Téllez,Víctor Varela-Guerrero,L. Huerta,Jesús Arenas-Alatorre
International Journal of Polymer Science , 2013, DOI: 10.1155/2013/235850
Abstract: Silver nanoparticles were synthesized and supported on thin nylon membranes by means of a simple method of impregnation and chemical reduction of Ag ions at ambient conditions. Particles of less than 10?nm were obtained using this methodology, in which the nylon fibers behave as constrained nanoreactors. Pores on nylon fibres along with oxygen and nitrogen from amide moieties in nylon provide effective sites for in situ reduction of silver ions and for the formation and stabilization of Ag nanoparticles. Transmission electron microscopy (TEM) analysis showed that silver nanoparticles are well dispersed throughout the nylon fibers. Furthermore, an interaction between nitrogen of amides moieties of nylon-6,6 and silver nanoparticles has been found by X-ray photoelectron spectroscopy (XPS). 1. Introduction Research on the synthesis of mesoporous materials containing nanoparticles represents a fast-developing area of nanoscience and nanotechnology. This interest is stimulated by several possible application areas of these materials including catalytic [1], magnetic [2], and optoelectronic [3, 4]. Metal nanoparticles dispersed in polymeric matrixes have recently been the subject of intense study aiming to develop nanocomposite films [5–8]. General approaches for the synthesis and support of nanoparticles inside porous materials include impregnation [9] and deposition-precipitation [10]. A drawback of this nanocomposites is the difficulty to disperse nanoparticles in most systems [11]; hence one potential advantage of such metal/polymer systems is that the size and distribution of dispersed metal nanoparticles can be readily controlled based on the properties of the host polymer [12, 13]. Silver particles with a narrow size distribution have been produced upon reversible chemical transformation between metallic and oxide states in a titania matrix [14] and in a mesoporous silica which was grafted with hydrophobic –Si(CH3)3 groups at the pore surface [15]. Nylon is an electron-rich and polar synthetic polymer (polyamide) usually made from the monomers adipoyl chloride and hexamethylene diamine to form a linear molecular chain (Figure 1). Synthetic nylon membranes have a porous structure [16] and are composed of microfibrils that are interconnected forming a three-dimensional network. Such morphological features provide a unique reaction vessel for synthesizing and supporting metal nanoparticles, allowing enhanced access of guest molecules to catalytic centres, compared with nonporous films. Figure 1: Characteristic synthesis of nylon-6,6 fibers. In this work,
Polymers Comprising Cholesterol: Synthesis, Self-Assembly, and Applications  [PDF]
Yuxiang Zhou,Victoria A. Briand,Nitin Sharma,Suk-kyun Ahn,Rajeswari M. Kasi
Materials , 2009, DOI: 10.3390/ma2020636
Abstract: This article reviews the current status of self-assembling liquid crystalline polymers comprising cholesterol. This article will focus on synthesis, structure-property relationships and strategies to direct ordering and packing of meso- and nanostructures of cholesterol polymers in the neat- or melt state and in solution. The applications of these self-assembled structures will be presented.
The MATCHIT Automaton: Exploiting Compartmentalization for the Synthesis of Branched Polymers  [PDF]
Mathias S. Weyland,Harold Fellermann,Maik Hadorn,Daniel Sorek,Doron Lancet,Steen Rasmussen,Rudolf M. Füchslin
Computational and Mathematical Methods in Medicine , 2013, DOI: 10.1155/2013/467428
Abstract: We propose an automaton, a theoretical framework that demonstrates how to improve the yield of the synthesis of branched chemical polymer reactions. This is achieved by separating substeps of the path of synthesis into compartments. We use chemical containers (chemtainers) to carry the substances through a sequence of fixed successive compartments. We describe the automaton in mathematical terms and show how it can be configured automatically in order to synthesize a given branched polymer target. The algorithm we present finds an optimal path of synthesis in linear time. We discuss how the automaton models compartmentalized structures found in cells, such as the endoplasmic reticulum and the Golgi apparatus, and we show how this compartmentalization can be exploited for the synthesis of branched polymers such as oligosaccharides. Lastly, we show examples of artificial branched polymers and discuss how the automaton can be configured to synthesize them with maximal yield. 1. Introduction Recently, small scale personal manufacturing has seen a rapid increase in popularity with emerging technologies such as 3D printing. In place of central production and physical distribution of goods, personal manufacturing offers a transfer of information (e.g., designs, protocols) followed by in-place, customizable production. Although mainly discussed in the context of macroscale personal manufacturing (i.e., 3D printing), personal manufacturing is also found in the domain of (bio-)chemistry. In custom oligonucleotide and peptide synthesis, the information, that is, DNA or protein sequence, is sent by the customer to the supplier. Even though the synthesized DNA oligonucleotides or peptides are shipped back to the customer (i.e., transfer of goods), this example demonstrates how transferred information can lead to in-place, customizable production of (bio)chemical goods. However, often the desired product cannot be synthesized via either one-pot synthesis or sequential one-pot synthesis. Consequently, distinct confinement and transport of substances and an elaborate temporal and spatial reaction management are needed. The European Commission funded project MATCHIT (Matrix for Chemical IT [1, 2]) aims to open the domain of chemistry for distributed manufacturing by implementing unconventional embedded computation systems. By employing addressable soft colloid supermolecular chemical containers (chemtainers) that act both as transport and reaction vessels and that are interfaced with electronic computers via microelectromechanical systems (MEMS), the topological
Sulfated Zirconia-Catalyzed Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones (DHPMs) Under Solventless Conditions: Competitive Multicomponent Biginelli vs. Hantzsch Reactions  [PDF]
Deyanira Angeles-Beltrán,Leticia Lomas-Romero,Victor H. Lara-Corona,Eduardo González-Zamora,Guillermo Negrón-Silva
Molecules , 2006, DOI: 10.3390/11100731
Abstract: The catalytic ability of ZrO2/SO42- to promote solventless three-componentcondensation reactions of a diversity of aromatic aldehydes, urea or thoiurea and ethylacetoacetate was studied. Products resulting from Hantzsch and/or Biginelli multi-component reactions are obtained in the presence of solid acid catalysts using the samereactants but different temperature conditions. The sulfated zirconia catalyst can berecovered and recycled in subsequent reactions with a gradual decrease of activity.
RECENT TECHNIQUES OF PHARMACEUTICAL SOLVENTLESS COATING: A REVIEW  [PDF]
Shital Dhuppe , S.S. Mitkare*, D.M. Sakarkar
International Journal of Pharmaceutical Sciences and Research , 2012,
Abstract: The coating of solid pharmaceutical dosage forms began in the 9th century B. C., with the Egyptians. Conventional coating techniques are based on solvents or water. Solventless coatings are alternative technique of coating. In solventless coating, the coating material is directly spread on the core and then it is cured by special method to form coat. Solventless coating avoids the use of water or it reduces to very small amounts with respect to the coating material hence it overcomes the limitations of conventional coating such as need for time, energy consuming, drying steps and the most important drug stability issues. A variety of solventless coating approaches are described in this review as powder coating, hot melt coating, supercritical fluid coating, magnetically assisted impaction coating, Plasma enhanced chemical vapor deposition. This review summarizes basic principle and process of the coating techniques.
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