Archana Moni Das

Synthesis and characterization of cellulose acetate from rice husk: Eco-friendly condition

Cellulose acetate was synthesized from rice husk by using a simple, efficient, cost-effective and solvent-free method. Cellulose was isolated from rice husk (RH) using standard pretreatment method with dilute alkaline and acid solutions and bleaching with 2% H2O2. Cellulose acetate (CA) was synthesized successfully with the yield of 66% in presence of acetic anhydride and iodine as a catalyst in eco-friendly solvent-free conditions. The reaction parameters were standardized at 80 °C for 300 min and the optimum results were taken for further study. The extent of acetylation was evaluated from % yield and the degree of substitution (DS), which was determined by (1)H NMR and titrimetrically. The synthesized products were characterized with the help modern analytical techniques like FT-IR, (1)H NMR, XRD, etc. and the thermal behavior was evaluated by TGA and DSC thermograms.

Synthesis of some new steroidal [16α,17α-d]-isoxazolines

Abstract Regioselective synthesis of novel steroidal anti-inflammatory ante drug analogues, viz., [16α,17α-d]-isoxazolines 1(a–h) and 2(a–h) prepared in a single step in good yield by the reaction of 16-dehydropregnenolone acetate (16-DPA) 1 or related 21-chloro-20-oxopregnane 2 with various aldoximes (a–h) in presence of chloramine-T in refluxing ethanol.

A convenient synthesis of the side chain of loteprednol etabonate—An ocular soft corticosteroid from 20-oxopregnanes using metal-mediated halogenation as a key reaction

A facile synthesis of the side chain of loteprednol etabonate, namely, chloromethyl-17α-[(ethoxycarbonyl))oxy]-11β-hydro of loteprednol etabonate, viz., chloromethyl-17α-[(ethoxycarbonyl))oxy]-11xy-3-oxoandrosta-1,4-diene-17β-carboxylate--an ocular soft corticosteroid, has been described starting from a 20-oxopregnane, namely, 3β-acetoxy-pregn-5(6),16(17)-diene-20-one (16-dehydropregnenolone acetate, i.e., 16-DPA) using our recently developed metal-mediated halogenation as a key reaction.

Extraction of cellulose from agricultural waste using Montmorillonite K-10/LiOH and its conversion to renewable energy: Biofuel by using Myrothecium gramineum

Cellulose was extracted from agricultural waste like Rice Husk (RH) a renewable resource of India as well as in the World. Cellulose was isolated from rice husk (RH) using eco-friendly method with Montmorillonite K-10/LiOH solution and bleaching with 2% H2O2. The reaction parameters like time, temperature, catalyst, acid and alkali were studied to evaluate the optimum reaction conditions 6h, 80°C, 20% maleic acid and 10% LiOH (in H2O) for time, temperature, acid and alkali, respectively. Renewable energy, biofuel from agricultural waste using Myrothecium gramineum was also investigated herein. Cellulose was converted to glucose by using acid hydrolysis and the optimum reaction conditions were 140°C for 60min. in presence of H2SO4 (5% v/v). It has been recognized significantly as potential sustainable sources of sugars for fermentation to bioethanol. So, our effort was given to obtain bioethanol from RH using new and novel renewable fungal strain M. gramineum. M. gramineum was isolated from acacia plant available in NE region of India. The results revealed that % yields of cellulose, glucose and bioethanol were 68%, 60% and 25%, respectively. Moreover, the bioethanol was compared with the standard ethanol (Laboratory grade) and also the ethanol produced from the known microb Aspergillus niger. The synthesized products were characterized with the help of analytical techniques like FT-IR, GC, TGA, DSC and XRD.

One-pot synthesis of chitosan–dehydropregnenolone acetate ketimine nanoparticles and their antifungal bioevaluation

This paper presents a new method for fabricating biodegradable bio-polymeric nanoparticles via a convenient one-pot strategy at room temperature under stirring conditions for application to communicable diseases. The simultaneous synthesis and assembly of chitosan–16-dehydropregnenolone acetate (CHDPA) nanoparticles were characterized using Fourier transform infrared (FT-IR) spectroscopy, and 1H NMR and UV vis analyses and the morphology along-with the particle size were identified using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In this study, the antifungal properties of the CHDPA nanoparticles were tested by measuring their antifungal activity against the fungus Colletotrichum gloeosporioides. The drug loading capacity (LC), encapsulation efficiency (EE) and drug release were investigated using UV spectrophotometry.

Synthesis of some novel steroidal 1,2,4,5-tetraoxanes

A facile synthesis of A-ring manipulated C-20 methyl carboxylate steroid derivative with unsymmetrical dispiro 1,2,4,5-tetraoxanes has been focused herein via acid catalyzed cyclocondensation of bis-epidioxy ketone. Novel stable unsymmetrical steroidal based spirocycloalkane 1,2,4,5 tetraoxane 8 has been developed from 3β-acetoxy-pregn-5(6), 16(17)-diene-20-one (16-dehydropregnenolone acetate, i.e. 16-DPA) 1 via metal-mediated halogenation as a key reaction.

Biogenic synthesis of gold nanoparticles and their application in photocatalytic degradation of toxic dyes

Plants and their extracts play an important role in the green synthesis of nanoparticles mainly because of their environmental benignity. Based on plant extracts number of metal nanoparticles have been synthesized. In our study, we report a green technique for the synthesis of gold nanoparticles using the aqueous extracts of Alpinia nigra leaves and their photocatalytic activities. The antioxidant, antibacterial and antifungal potential of the synthesized nanoparticles were also evaluated. The aqueous extract of the plant is rich in flavonoids with Total Flavonoid Content of 491mgRE/g extract. The presence of flavonoids was further confirmed through analytical High Performance Liquid Chromatography (HPLC) analysis. The A. nigra mediated syntheses of gold nanoparticles (ANL-AuNPs) were characterized by UV-Vis spectrophotometer, Fourier Transform Infrared (FTIR) Spectroscopy, X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The crystalline nature of the ANL-AuNPs was confirmed by the powder XRD analysis. The TEM micrographs showed that the ANL-AuNPs was predominantly spherical in shape and the average particle size was 21.52 nm. The polyphenolics and other functional groups present in the aqueous extract that acted as reducing and capping agent in the synthesis of the Au-NPs were identified via FTIR spectral analysis. These green synthesized nanoparticles exhibited antioxidant activity with IC50 value of 52.16 μg/ml and showed inhibition in the growth of both gram-positive and gram-negative bacteria. The pathogenic fungus, Candida albicans was also susceptible to these nanoparticles. The ANL-AuNPs in the presence of sunlight catalyzed the degradation of the anthropogenic pollutant dyes, Methyl Orange and Rhodamine B with percent degradation of 83.25% and 87.64% respectively. The photodegradation process followed pseudo first order kinetic model. These results confirm that Alpinia nigra is a potential bioresource for the synthesis of Au-NPs with versatile applications.

Synthesis of cellulose impregnated copper nanoparticles as an efficient heterogeneous catalyst for C N coupling reactions under mild conditions

Highly efficient copper nanoparticles supported over nanocellulose have been prepared by a simple chemical reduction method. The cellulose was extracted from the inner stem of Hibiscus sabdariffa and used as a polymer matrix for the synthesis of copper nanoparticles. The formation of the nanoparticles was validated through different characterization techniques like X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), UV-vis spectroscopy (UV) and Energy dispersive X-Ray Spectroscopy (EDX). Moreover the morphology of the cellulose supported copper nanoparticles was investigated using field emission scanning electron microscope (FESEM) and field emission transmission electron micrograph (FETEM) which revealed the formation of spherical nanoparticles with an average size of 7 nm. The synthesized catalyst was then utilized effectively in the CN coupling reactions involving open chained as well as cyclic secondary amines and electron deficient vinylic compounds. The catalyst demonstrated excellent yield (82%-95%) and was easily recycled for upto six cycles without any significant loss of catalytic activity.