B. S. R. Reddy

Synthesis and characterization of new epoxy and cyanate ester resins

Abstract New epoxide and cyanate ester resins with an aromatic ester backbone namely 1,3-[di-(4-glycidyloxy diphenyl-2,2′-propane)]-isophthalate (DGDPI) and 1,4-[di-(4-cyanato diphenyl-2,2′-propane)]-terephthalate (DCDPT) were synthesized and the intermediates were characterized by IR, 1 H-/13C-NMR spectroscopic methods. The cured products from DGDPI and DHDPI exhibited higher Tg compared with standard epoxy system. The increase in the Tg may be due to the cyanate ester and rigid aromatic backbones present in the curing system.

4-CHLOROPHENYL ACRYLATE AND GLYCIDYL METHACRYLATE COPOLYMERS: SYNTHESIS, CHARACTERIZATION, REACTIVITY RATIOS, AND APPLICATION

4-Chlorophenyl acrylate (CPA) and glycidyl methacrylate (GMA) copolymers having different copolymer compositions were synthesized in 1,4-dioxane using benzoyl peroxide as initiator at 70 ± 0.5°C. Using 1H-NMR spectroscopy, the composition of the two monomers in the copolymers were calculated by comparing the integral values of the aromatic and alifatic proton peaks. The reactivity ratios (average r1 = 0.03 ± 0.04 and r2 = 2.27 ± 0.55) were calculated by Fineman-Ross, Kelen-Tudos and extended Kelen-Tudos methods. The copolymers were characterized by 1H and proton decoupled 13C-NMR spectroscopies. Gel permeation chromatography was employed for estimating the Mw and Mn and Mw/Mn of the homo- and co-polymers. Thermal analysis showed copoly(CPA-GMA) (49:51) to be less stable (345°C) than poly(CPA) (417°C) at 50°C. DSC was utilized in determining the glass transition temperature. The 49:51 copolymer was chosen for making adhesives by curing with diethanolamine in chloroform. The cured resins were tested for the...

Synthesis, characterization and pharmacologically active sulfamethoxazole polymers

Abstract Three anti-microbial pharmaceutical drugs were synthesized from two different synthetic routes. 4-acrylamido-N-(5-methyl-3-isoxazolyl)benzenesulfonamide (AMBS) and 4-methacrylamido-N-(5-methyl-3-isoxazolyl)benzenesulfonamide (MMBS) were prepared by reacting acryloyl chloride and methacryloyl chloride with 4-amino-N-(5-methyl-3-isoxazolyl)benzenesulfonamide in the presence of triethylamine. N-[4-sulfamido-N-(5-methyl-3-isoxazolyl)phenyl]maleimide (SMPM) was prepared by reacting maleic anhydride with 4-amino-N-(5-methyl-3-isoxazolyl)benzenesulfanamide. These monomers (AMBS, MMBS and SMPM) were polymerized using BPO as a free radical initiator. The pharmacological activity of SMPM compound depends on the functional group in the structure and small structural changes has resulted in higher pharmacological activity of sulfamethoxazole. Thus, maleimide polymer drug conjugate showed greater anti-microbial activity when compared with that of the native drug.

Facile and diastereoselective synthesis of 3,2'-spiropyrrolidine-oxindoles derivatives, their molecular docking and antiproliferative activities.

In the present study, a series of novel highly functionalized spiropyrrolidine-oxindoles have been synthesized through 1,3-dipolar cycloaddition of an azomethine ylide formed from isatin and various amino acids such as sarcosine, proline and thioproline with the dipolarophile (E)-3-(1,3-diphenyl-1H-pyrazol-4-yl)-2-(1H-indole-3-carbonyl)acrylonitrile under optimized conditions. All the synthesized compounds were evaluated for their antimicrobial activity and shown significant activity.

Novel activated acrylates: synthesis, characterization and the reactivity ratios of 4-acetamidophenyl acrylate copolymers with methyl methacrylate and glycidyl methacrylate

Abstract A new functional activated acrylate, 4-acetamidophenyl acrylate (APA) was synthesized and characterized by IR, 1 H- and 13 C-NMR and mass spectra. Homo and copolymers of APA with MMA and GMA were prepared by free radical polymerization. All the copolymer compositions have been determined by 1 H-NMR and the reactivity ratios of the monomer pairs have been evaluated. APA (r1): 1.099 and MMA (r2): 1.210 for copoly(APA–MMA) system. APA (r1): 0.648 and GMA (r2): 1.30 for copoly(APA–GMA) system. Thermal stability and molecular weights of the copolymers were reported.

Ring Opening Metathesis Polymerization of Polyoctahedral Oligomeric Silsesquioxanes (POSS) Incorporated Oxanorbornene-5,6-dicarboximide: Synthesis, Characterization, and Surface Morphology of Copolymers

The synthesis and characterization of N-propyl-POSS-7-oxanorbornene-5,6-dicarboximide (NPONDI) and N-3-(trifluoromethyl)phenyl-7-oxanorbornene-5,6-dicarboximide (TFNDI) was reported. The synthesis of the POSS-based (co)polymers were accomplished by ring opening metathesis polymerization (ROMP). The monomers and polymers were characterized using FT-IR, 1H-, 13C-, 29Si-NMR, and GPC techniques. Thermal properties of TFNDI-NPONDI copolymers were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Transmission electron microscopic (TEM) analysis of optically transparent and flexible copolymer films revealed the presence of 50 nm-sized POSS agglomerates. Atomic force microscopy analysis of the film surface exhibited a modest increase in surface roughness of TFNDI-NPONDI copolymers as compared with homopoly[N-3(trifluoromethyl)phenyl-7-oxanorbornene-5,6-dicarboximide] (HTFNDI). The POSS incorporated polymers such as 1NPONDI, 2NPONDI, and 3NPONDI increased the hydrophobicity as compared with HTFNDI. This was measured by static contact angle analysis. The study focussed on the dispersion, surface morphology, and the microstructure of POSS in TFNDI-NPONDI copolymer as determined by scanning electron microscopy (SEM).

Auto-fluorescent mesoporous ZnO nanospheres for drug delivery carrier application.

The zinc oxide (ZnO) nanostructures are very interesting materials because of their practical bio-applications in various areas such as drug delivery, construction of biomaterial, optical and acoustic devices as well as their bactericidal properties. Herein, we have prepared spheroidal mesoporous auto-fluorescent ZnO nanospheres by modified continuous distillation method, showed a blue emission in the concentration of 2mg/ml at 444nm. The auto-fluorescent property of ZnO nanospheres can be used in biomaterials for target sites of tissues/cells, thereby enabling site drug delivery especially in cancer therapy. Initially, the auto-fluorescent property of the ZnO material was characterized by different techniques like PXRD, FESEM with EDAX graph, TEM, ICP-OES, particle sizes, zeta potentials and BET analysis. The mesoporous ZnO nanospheres has attracted well for their crystalline, functionalized and intensified fluorescent properties. The surface of the ZnO nanospheres was porous, spherical and nanometric in size. The synthesized material has enormous potential as a nano-drug-carrier. Preliminary studies indicated that the material prepared has an excellent scope for detection and delivery at the site of therapeutic action.

Rapid Access to Tricyclic Systems: Highly Endoselective Diels-Alder Reaction of Cycloalkenones with Cyclic Dienes Under Microwave Irradiation

Abstract Cis fused ring systems are synthesized in good yields under microwave irradiation conditions in the presence of AlCl3 as a catalyst within short time periods.

Starch nanocrystals based hydrogel: Construction, characterizations and transdermal application.

Bio-based nanocomposites were prepared using starch nanocrystals obtained by acid hydrolysis of native starches using different acid sources. In recent times, focuses on starch nanocrystals (SNCs) have been increasing in number of research works dedicated to the development of bio-nanocomposites by blending with different biopolymeric matrices. The work mainly deals with the preparation of starch nanocrystals using different native starches by acid hydrolysis using hydrochloric acid and trifluroacetic acid. The as-prepared starch nanocrystals are having high crystallinity and more platelet morphologies, and used as a drug carrying filler material in the hydrogel formulations with the care of different polymer matrices. The condensed work also concentrates on the dispersion of antiviral drug in the hydrogels, which are applied onto biocompatible bio-membrane to be formulating a complete transdermal patch. The acid hydrolysed starch nanocrystals were thoroughly characterized using TEM, SEM, particle size analysis and zeta potential. Their thermal stability and the crystalline properties were also characterized using TG-DSC and XRD respectively. The physiochemical interaction and compatibility between the drug and the SNCs filler in the polymeric hydrogels were evaluated using FT-IR analysis. The formulated hydrogels were subjected to evaluation of in vitro permeation studies using Franz diffusion studies. The in vitro study was indicated substantial guarantee for the fabrication of drug dispersed in polymeric hydrogels using SNCs as filler matrices for a successful transdermal drug delivery.

Facile fabrication of mesoporous ZnO nanospheres for the controlled delivery of captopril

In the present study, to formulate captopril in a hierarchical porous structure of ZnO nanospheres by means of the soluble-starch-insertion method, state of drug carrier delivery toward oral route and the mode of delivery in suitable medium. Mesoporous ZnO nanospheres were synthesized by simple soluble-starch-insertion method, followed by loading of captopril using ultrasonic force. The materials were characterized by PXRD, SEM, FESEM, TEM, TGA, FT-IR, and BET analyses, and biocompatibility studies. Captopril-loaded porous ZnO nanospheres were evaluated as in vitro drug-release studies and its kinetic models. Crystallite plane arrangement, functional groups, materials morphology, and porosity of porous ZnO nanospheres were confirmed. Larger surface area and distribution in constrained pores on its surface make the nanospheres suitable for high drug loading of captopril. The ZnO nanocrystallites have given porous properties on the spherical surface leads to the drug adsorption. The loading and release studies (in vitro in simulated gastric and intestinal fluids) have shown that both were affected by the mesoporous nanospheres’ surface properties of the ZnO materials and its biocompatibility has also been proved. Therefore, the in vitro experiments have indicated the considerable promise of mesoporous ZnO nanospheres, fabricated by the soluble-starch-insertion method acting as a biocompatible carrier for the controlled delivery of captopril in oral route of administration.Graphical Abstract