C. Devendranath 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 antibacterial activity of 2-alkylcarbamato/trichloromethyl/chloroethoxy/aryloxy-1,2,3,4-tetrahydro-1,3,2-benzodiazaphosphorine 2-oxides

Several 2-trichloromethyl/2-chloro-ethoxy/2-aryloxy-1,2,3,4-tetrahydro-1,3,2-benzodiaza-phosphorine 2-oxides (4a–d), and 2-alkyl/alkenyl/alkynylcarbamato 2-oxides (7a-f) have been synthesized from reactions of equimolar quantities of 2-aminobenzylamine (2) with various aryl or alkyl phosphorodichloridates (3b–d), trichloromethylphosphonic dichloride (3a) and dichlorophosphinyl carbamates (6a–f) at 40–50°C in dry toluene in the presence of triethylamine. IR, 1H, 13C, 31P NMR and mass spectral analyses were collected and analyzed and supported all structures. The title compounds were screened for antibacterial activity against Bacillus subtilis and Escherichia coli. Several of the agents exhibited significant activity in the assays.

SYNTHESIS OF 8-SUBSTITUTED-16H-DINAPHTHO [2,1-d:1′,2′-g] 1, 3, 2-DIOXAPHOSPHOCIN 8-OXIDES

Abstract A new family of phosphorus heterocycles, namely 8-substituted-16H-dinaphtho[2, 1-d: 1′,2′-g]1, 3, 2- dioxaphosphocin 8-oxides, has been obtained via a synthesis from reaction of bis(2-hydroxy-1-naphthyl)methane with a series of aryl phosphorodichloridates in dry benzene in the presence of triethylamine. NMR analysis of a solution of the title compounds revealed essentially no coupling between the bridged methylene protons and the P atom which suggested the dioxaphosphocin ring may exist in a boat conformation in solution. An X-ray diffraction analysis of a crystal of 8-(2′,3′-dimethylphenoxy)- 16H-dinaphtho[2,1-d:1′,2′-g]1,3,2-dioxaphosphocin 8-oxide does indicate that in the solid state the dioxaphosphocin ring is in a distorted and extended boat-like conformation with the P[dbnd]O and bridged CH2 groups directed away from each other. Electron impact mass spectral analysis confirmed the structures of the esters and showed M+, (M — R)+, and (M – OR)+ ions containing the dioxaphosphocin ring system.

Synthesis and TGA Evaluation of Novel Triphosphate Esters

Several new substituted organo tri/thiotriphosphate esters were synthesized by condensing cyclic oxaza/dioxaphosphorochloridates/ thiochloridates with K2HPO4 in the presence of tetrabutylammonium iodide. The functionality on the phosphate was systematically changed by synthesis, thus allowing evaluation and comparison of a range of phosphate esters with highly varied structural features. They were subjected to thermogravimetric analysis, derivative thermogravimetric analysis, and differential thermal analysis to assess their thermal stability and potential use as flame retardants. It has been found that their thermal degradations, being highly complex and dependent upon a number of molecular structural features, are difficult to rationalize on simple rules.

Oxone as a Mild, Inexpensive, and Environmentally Benign Oxidant for the α-Thiocyanation of Ketones

Abstract An efficient and direct approach for the α-thiocyanation of ketones with α-hydrogens has been developed using ammonium thiocyanate as a thiocyanating agent and oxone as an oxidant in methanol.

SYNTHESIS OF 6-ARYLOXY- AND 6 p-TOLYLTHIOXY 2,10-DICHLORO-12-TRICHLOROMETHYL-12H-DIBENZO[d,g]-[1,3,2]DIOXAPHOSPHOCIN 6-OXIDES

Abstract 6-Aryloxy- and 6-p-tolylthioxy-2,10-dichloro-12-trichloromethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-oxides were synthesized and characterized by IR, 1H, 13C, 31P, and mass spectral analyses for the first time. The 1H chemical shifts for H(12) at the carbon bridge occurred between δ 6.15 and 6.40 which suggested a common environment and one conformer, but the presence of more than one conformer in each example cannot be entirely eliminated. Obviously the trichloromethyl groups attached to C(12) induces a significant downfield shift of H(12). An X-ray diffraction analysis of solid 6-(4′-chlorophenoxy)-2,10-dichloro-12-trichloromethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-oxide (3j) shows it is a boat-chair with the trichloromethyl group in a pseudo equatorial arrangement and with the phosphoryl group in a “down arrangement” of a boat-chair conformer. An interesting by-product, namely triethylammonium 2-methylphenyl 2-[[2′,2′,2′-tichloro-1′-(2″-hydroxyl-5″-chlorophenyl)}ethyl]-4-chlorophenyl...

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.

Syntheses and Antimicrobial Activity of Some Novel 6‐Substituted Dibenzo[d, f][1,3,2]dioxaphophepin‐6‐oxides, Sulfides, and Selenides

Abstract 6‐Substituted‐dibenzo[d, f][1,3,2]dioxaposphepin‐6‐oxides, sulfides, and selenides (5a–i, 6a–d, and 7a–d) were synthesized by reacting 2,2′‐biphenol (1) with phosphorus tribromide in the presence of triethylamine at 0–30°C and subsequent reaction of the monobromide (2) with different Grignard reagents (3) at room temperature. The products (4) were converted to corresponding oxides, sulfides, and selenides (5a–i, 6a–d, and 7a–d) by oxidation with H2O2 at room temperature and refluxing with sulfur and selenium respectively. The chemical structures of all the products were confirmed by analytical, IR, NMR (1H, 13C, and 31P), and mass spectral data. Most of these compounds exhibited moderate antimicrobial activity.

SYNTHESIS OF 2-ARYLOXY-6-METHYL-4-TRICHLOROMETHYL-4H-1,3,2-BENZODIOXAPHOSPHORIN 2-OXIDES/SULFIDES

Abstract Synthesis of 2-aryloxy-6-methyl-4-trichloromethyl-4H-1,3,2-benzodioxaphosphorin 2-oxides and corresponding 2-sulfides and their IR, 1H, 13C and 13P NMR spectral analyses were reported. Long-range 3J H–P, 2J PDC and 3 J POCC couplings were determined. An X-ray diffraction analysis of a crystal of 2(2′,6′dimethylphenoxy)-6-methyl-4-trichloromethyl-4H-1,3,2-benzodioxaphosphorin 2-oxide suggested distorted-boat conformation for the dioxaphosphorin ring with P[dbnd]O directed away from the ring. Electron impact mass spectra exhibited M+, (M[sbnd]Cl) +, (M[sbnd]Cl)[sbnd]-HCl)+ and (M[sbnd]CCl3)+ as major ions with the dioxaphosphorin ring intact supporting the proposed structures of these esters. Toxicity of some of the compounds against the insect, P. americana, was evaluated and their LD50 values were reported.

Synthesis and antimicrobialactivity of 2‐alkylcarbamato‐2,3‐dihydro‐5‐propylthio‐1H‐1,3,2‐benzodiazaphosphole 2‐oxides

Novel 2-alkylcarbamato/thiocarbama-to-2,3-dihydro-5-propylthio-1H-1,3,2-benzodiazaphos-phole 2-oxides (4a–J) were synthesized by cyclization of 4-propylthio-1,2-phenylenediamine (3) with the corresponding dichlorophosphoryl carbamates/thiocarbamates (2a–J) that were obtained by the addition of alcohols/thiols to isocyanatophosphoryl dichloride (1). The structures of the title compounds were confirmed by the 1H, 13C, 31P NMR, and mass spectral studies. Some of these products were found to possess significant antimicrobial activity.