K. R. Desai

A facile microwave enhanced synthesis of sulfur-containing 5-membered heterocycles derived from 2-mercaptobenzothiazole over ZnCl 2/DMF and antimicrobial activity evaluation

An efficient and extremely fast procedure for the synthesis of 4-thiazolidinones 4a–j by the reaction of arylidene-[(2-benzothiazolylthio)-acetamidyl] 3a–j with thioglycolic acid in DMF in the presence of a catalytic amount of anhydrous ZnCl 2 under microwave irradiation is described. A considerable increase in the reaction rate has been observed with better yield in microwave technique. All the compounds have been screened for their antifungal activity against Candida albicans (ATCC-64550), Candida krusei (ATCC-14243) and Candida parapsilosis (ATCC-22019) and antibacterial activity against Escherchia coli (Gram−ve) (ATCC-8739), Staphylococcus aureus (Gram+ve) (ATCC-6538) and Bacillus substilis (Gram+ve) (ATCC-6633). The structures of the synthesised compounds 4a–j have been characterized on the basis of their elemental analysis and spectral data.

Synthesis and Characterization of Colored Polyureas

ABSTRACT Various disperse dyes based on m-phenylenediamine have been prepared. These dyes were then polycondensed with Toluene 2, 4-diisocyanate. The resultant colored polyureas were characterized by elements analyses, IR spectral studies, estimation by monaqueous conductometric titration and thermogravimetry. All the polyureas were subjected to electrical conductivity determination at room temperature.

Novel Organophosphorus Compounds as Potential Antimicrobial Agents

The 4-Thiazolidinone derivatives of phenophosphazines were synthesized by a reaction of Schiff base derivative of phenophosphazine with Thyoglycollic acid in molar ratio of 1:3 using DMF as solvent. Possible structures have been proposed based on elemental analysis, IR and 1 H NMR spectral studies. The antibacterial and antifungal activities of these derivatives have been evaluated against pathogens E. coli, S. typhi, S. aureus, B. subtilis, A. niger, and C. Albicans.

A Convenient, Rapid Microwave-Assisted Synthesis of 2-Substituted Phenyl-2,3-Dihydrobenzo[B][1,4]Thiazepine-3-Carboxamide Derivatives and Its Antimicrobial Activity

Abstract Using an environmentally benign procedure under microwave irradiation, a variety of 4-methyl-N-(4-(2-oxo-2H-chromen-3-yl)thiazol-2-yl)-2-substituted phenyl-2,3-dihydrobenzo [b][1,4]thiazepine-3-carboxamide compounds were synthesized from 2-arylidene-3-oxo-N-(4-(2-oxo-2H-chromen-3-yl)thiazol-2-yl)butanamide. Structures of these compounds were confirmed by IR, NMR (1H & 13C), and mass spectral analyses. Also, a considerable increase in the reaction rate has been observed with better yield in the microwave technique. The newly synthesized compounds were evaluated for antimicrobial activity against a variety of bacterial strains, and some of these compounds have shown significant antibacterial and antifungal activities. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Biological Activity. GRAPHICAL ABSTRACT

Synthesis and Characterization of Colored Poly(Urethane-Urea)

ABSTRACT Various Poly(urethane-urea)s (PUU)s were prepared by polycondensation of various azo dyes having both amino and hydroxyl group with Toluene 2,4-diisocyanate. The resultant poly(urethane-urea)s were characterized by the elementary analysis, IR spectral, nonaqueous conductometric titration, and thermogravimetry. The electrical conductivity of these oligomers has also been measured at room temperature.

Synthesis and Characterization of Novel Colored Polyurethanes

ABSTRACT Azo disperse dyes containing N, N-diethylol group have been prepared and each dye was polycondensed with 4,4′ -Diphenyl methane diisocyanate. The resultant colored polyurethanes were characterized by nitrogen content, IR spectral studies, number average molecular weight ([Mbar]n), estimated by conductometric titration, and thermogravimetry. The electrical conductivity of all the polyurethanes was measured at room temperature.

Poly (Urethane-Urea)s: Part-4

Abstract Poly(urethane-urea)s (PUUs) were prepared by polycondensation of different aminoalcohols and aminophenols/naphthols with various diisocyanates. The resultant poly(urethane-urea)s were characterized by elemental analyses, IR spectral studies, number average molecular weight (Mn) estimated by non-aqueous conductometric titration and thermogravimetry. The electrical properties of these polymers have also been measured at room temperature.

Esterification and hydrolysis under microwave irradiation

p-methoxy benzoicacid 1 (1.67 g, 0.01 mole) and catalytic amount of conc. H2SO4 (2-3 drops) in absolute methanol (30 mL) was taken in RBF placed in a microwave oven and irradiated (400w, 61-62oC) for 2.5 min [1].[...]

Polyimides Based on Poly(2-Furanmethanol-Formaldehyde), Part 1

Abstract Polyimides were prepared by Diels-Alder (DA) reaction of furan resin namely Poly[2-furanmethanol-formaldehyde] (PFF) with various bismaleimides. The DA reaction was carried out in tetrahydrofuran (THF) as solvent, as well as in bulk, followed by aromatization of tetrahydropthalimide intermediates in the presence of acetic anhydride. All the polyimides were characterized by elemental analysis, infrared (IR) spectral studies and thermogravimetry. The results show that polyimides based on FF resin exhibit good thermal stability. Preliminary test for glass reinforcement of the polyimides indicate that laminate with good mechanical strength can be prepared.

Synthesis and Antimicrobial Activity of Substituted Phenophosphazines

Several Schiff base derivatives of phenophosphazines were synthesized by the reaction of amino phenophosphazines and aromatic aldehydes in equimolar ratio, using methanol as solvent. Possible structures have been proposed on the basis of elemental analysis, IR, and 1H NMR spectral studies. The antibacterial and antifungal activities of the above mentioned Schiff base derivatives have been evaluated against pathogens E. coli, S. typhi, S. aureus, B. subtilis, A. niger, and C. Albicans.