M. Veera Narayana Reddy

PEG-SO3H catalyzed synthesis and cytotoxicity of α-aminophosphonates

One pot three-component PEG-SO(3)H catalyzed reaction of 4-(Pyridin-4-yl)benzaldehyde and triethyl phosphite with various primary amines afforded α-aminophosphonates with high yields by the Kabachnik-Fields reaction. These new structurally diversified set of α-aminophosphonates (4a-j) were evaluated for their anti-tumor activity on human chronic myeloid leukemia cells (K 562), human colon carcinoma cells (Colo 205) along with non-cancerous human embryonic kidney cells (HEK 293). They showed moderate activity on both cancerous cells and non-cancerous cells.

Synthesis and bio-activity evaluation of tetraphenyl(phenylamino) methylene bisphosphonates as antioxidant agents and as potent inhibitors of osteoclasts in vitro.

A new series of tetraphenyl bisphosphonates have been elegantly synthesized by one-pot method and were characterized by elemental analysis, FTIR, 1H, 13C, 31P NMR, mass spectra and evaluated for their in vitro antibone resorptive activity by inhibiting growth of osteoclasts. Two bisphosphonates 3g and 3f showed marked inhibition ratio (8 μM and 10 μM) and emerged as lead compounds. All compounds were tested for their antioxidant (DPPH scavenging, reducing power and inhibition of lipid peroxidation). They exhibited potent in vitro antioxidant activity dose-dependently.

Green Synthesis of Aminobisphosphonates Under Microwave Irradiation

Abstract A simple, efficient, and environmentally benign green chemical method has been developed for the synthesis of aminobisphosphonates by reacting aliphatic/aromatic 2°-amines, dimethylphosphite, and triethylorthoformate by microwave irradiation under solvent-free conditions, in the presence of an alumina solid support. The advantages of this method are less reaction time, simple work-up, and excellent yields. 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 and antimicrobial activity of bisphosphonates

Dimethyl [(substitutedphenyl)(6-oxo6λ5dibenzo[d,f][1,3,2]dioxaphophepin-6-yl)methyl]phosphonates (5a-j) were synthesised through a three step process involving preparation of dimethyl hydroxy(substitutedphenyl)methyl-phosphonates (4a-j) and their reaction with 6-bromodibenzo[d,f][1,3,2]dioxaphosphepine (2) in dry toluene in the presence of triethylamine at 50–60°C. Tetramethylguanidine (TMG) as a catalyst was found to increase the yields and purity of the products. These compounds were characterised by IR, 1H, 13C, 31P NMR and mass spectral data found to possess higher antimicrobial activity then the standards.

Synthesis and Bioassay of Alkyl-2-[(5,6-dimethyl-2-sulfido-1,3,4,7,2-dioxadiazaphosphepin-2-yl)amino] Alkyl/Aryl Esters

Synthesis of alkyl-2-[(5,6-dimethyl-2-sulfido-1,3,4,7,2-dioxadi- azaphosphepin-2-yl)amino]alkyl/aryl esters (3a–j) was accomplished via a two-step process. It involves the prior preparation of monochloride intermediate (2) and its subsequent reaction with the amino acid esters in dry tetrahydrofuran in the presence of triethylamine at reflux temperature. These compounds were characterized by infrared (IR), 1H-, 13C-, and 31P-nuclear magnetic resonance (NMR), and mass and elemental analysis and were found to exhibit potent antimicrobial activity.

Solvent-free synthesis of novel 2,10-dichoro-12-trichloromethyl-6-substituted xanthato-12H-dibenzo[d,g] [1,3,2] dioxaphosphocin-6-sulfides

Abstract 2,10-Dichloro-12-trichloromethyl-6-substituted xanthato-12H-dibenzo[d,g] [1,3,2] dioxaphosphocin-6-sulfides (2a–l) with the eight-membered phosphorus and oxygen heterocyclic ring were synthesized by reacting equimolar quantities of alcohols, carbon disulfide, and 2,6,10-trichloromethyl-12H-dibenzo[d,g][1,3,2] dioxaphosphocin-6-sulfide 1 in the presence of dimethylaminopyridine (DMAP). The structures of the products were confirmed by IR, 1H, 13C, 31P-NMR, and mass spectral analyses.

Preparation of Tetraoxadiphosphadiborocane-2,6-diones

Abstract Cyclization of aryl/alkyl phosphonic dichlorides (2a–f) with phenylboronic acid/K2CO3/I2 in dry toluene at 60–70 °C afforded 2,6-diaryl/alkyl-4,8-diphenyl-1,3,5,7,2λ 5,6λ 5,4,8-tetraoxadiphosphadiborocane-2,6-diones (3a–f). GRAPHICAL ABSTRACT