V. Koteswara Rao

Synthesis, spectral characterization and biological evaluation of phosphorylated derivatives of galanthamine

A series of novel phosphorylated derivatives of galanthamine 6-11 and 12-17 were synthesized in two step process with high yields. In the first step galanthamine 1 was reacted with bis (2-chloroethyl) phosphoramidic dichloride 2/4-nitrophenyl phosphorodichloridate 3 in presence of triethylamine (TEA) in dry tetrahydrofuran (THF) yielded the intermediates 4/5. They were further reacted with various compounds like 2-aminoethanol, ethyleneglycol, ethylenediamine, 2-aminoethanethiol, 2-hydroxyethanethiol, monopotassium dihydrogenphosphate to obtain the title compounds 6-11 and 12-17. The title compounds showed promising antimicrobial, antioxidant activities and was greatly influenced by the presence of different bioactive groups.

Synthesis of Schiff's bases in aqueous medium: a green alternative approach with effective mass yield and high reaction rates

Abstract Schiffs bases constitute a class of pharmaceutical and medicinally important molecules. The conventional methods for the synthesis of Schiffs bases require long reaction times and use of organic solvents. We report a novel and eco-friendly condensation reaction method permitting the “green synthesis” of various Schiffs bases by stirring 1,2-diaminobenzene with various aromatic aldehydes in water as solvent. This method is experimentally simple, clean, high yielding, green, and with reduced reaction times. The product is purified by simple filtration followed by washing with water and drying processes.

Synthesis, Antimicrobial, and Antioxidant Activity of New α-Aminophosphonates

Abstract A new class of α-aminophosphonates 2–16 has been synthesized by the reaction of equimolar quantities of Schiffs bases with diethyl/dimethyl/diphenyl phosphite in dry toluene under reflux conditions using tetramethylguanidine (TMG) as a catalyst via Pudovik reaction in high yields (78–89%). The structures of the title compounds have been established by elemental; infrared (IR); 1H-, 13C-, and 31P-NMR; and mass spectral data analyses. They were found to possess significant antimicrobial and antioxidant activity. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT

Synthesis, spectral characterisation and anti-microbial activity of novel 3-substituted-2, 4-dihydro-12H-3λ 5- -tribenzo [ f, j, n ] [1, 5, 9, 12, 3] dioxadiazaphosphacyclopentadecine-3-selones

Tris(bromomethyl)phosphineoxide and 2-[(2-[(Z)-1-(2-hydroxyphenyl)methylidene]aminophenyl)imino]methylphenol have been utilised as precursors in the synthesis of novel pentaco-ordinate dioxadiazaphosphacyclopentadecines[e.g. 3-[(2-hydroxyethoxy)methyl]-2,4-dihydro-12H-3λ5-tribenzo[f, j, n][1,5,9,12,3]dioxadiazaphosphacyclopentadecine-3-selone] in moderate (overall) yields. The synthesised compounds were characterised by elemental and spectral (IR, 1H, 13C, 31P NMR and MS) studies and their anti-microbial activity was evaluated.