E. Dadapeer

Polyethylene Glycol–Promoted Dialkyl, Aryl/Heteroaryl Phosphonates

Abstract A new, straightforward polyethylene glycol–promoted method for Michaelis–Arbuzov rearrangement has been described.

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.

Synthesis, spectroscopic characterisation, electron microscopic study and thermogravimetric analysis of a phosphorus-containing dendrimer with phloroglucinol as a core unit

A phosphorus-containing dendrimer of up to four generations with phloroglucinol as a core unit was synthesised using a divergent growth method. A repetitive synthetic sequence of several types of reactions was performed by using P(O)Cl3, 3-hydroxybenzaldehyde, 4-hydroxybenzaldehyde and p-phenylenediamine for the synthesis of this dendritic molecule G4 involving simple condensation reactions. This Schiffs base macromolecule possesses 12 imine bonds and 6-OH groups on the periphery. The structures of the intermediate generations G1, G2, G3 were confirmed by IR, 1H, 13C, 31P NMR and LC/EI MS. The final dendrimer G4 was characterised by IR, 1H, 13C, 31P NMR, Maldi-tof mass spectrometer and C, H, N analysis. The scanning electronic microscopic study and thermogravimetric analysis were also performed for the final dendrimer (G4).

Synthesis, spectral characterization, electron microscopic study and thermogravimetric analysis of a phosphorus containing dendrimer with diphenylsilanediol as core unit.

Summary A phosphorus containing dendrimer with a diphenylsilanediol core was synthesized using a divergent method. Several types of reactions were performed on dendrons of several sizes, either at the level of the core or the surface. The giant Schiff’s base macro molecule possesses 12 imine bonds and 8 hydroxy groups on the terminal phenyl groups. The structures of the intermediate compounds were confirmed by IR, GCMS and 31P NMR. The final compound was characterized by 1H, 13C, 31P NMR, MALDI-TOF MS and CHN analysis. Scanning electron microscopic and thermogravimetric analysis/differential scanning calorimetric studies were also performed on the final dendritic molecule.

Synthesis, Characterization, and Thermogravimetric Studies of a Phosphorus-Containing Dendron Built from 1,5-Diaminonaphthalene at the Core

Abstract A facile divergent synthesis of a phosphorus-containing dendron containing 1,5-diaminonaphthalene is described. The phosphorus-containing dendron, functionalized with a 1,5-diaminonaphthalene unit at the core and phenolic OH groups grafted at the periphery, has been accomplished in a versatile, simple fashion, using Schiffs condensation and nucleophilic substitution reactions with POCl3, 3-hydroxy-benzaldehyde, 4-hydroxy-benzaldehyde, and 3-amino-phenol iteratively. The structures of intermediate dendrons were characterized by infrared, NMR (1H, 13C, and 31P), liquid chromatography–mass spectrometry, and C, H, N analysis. The structure of the final dendron (6) was confirmed by infrared, NMR (1H, 13C, and 31P), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and C, H, N analysis. The thermal stability and degradation of the resulting final dendron was checked by thermal gravitometric analysis/differential thermal analysis. GRAPHICAL ABSTRACT

Facile iterative synthesis, spectral characterization, electron microscopic study and thermogravimetric analysis of phosphorus dendron with bisphenol A at the focal point

A facile iterative synthesis of a phosphorus dendron with bisphenol A at the focal point by following the divergent procedure is described. The phosphorus dendron peripherally functionalized with phenolic OH group has been accomplished in a very versatile simple fashion, using the Schiff condensation and nucleophilic substitution reactions using P(S)Cl3, P(O)Cl3, 3-hydroxybenzaldehyde and 3-aminopheno. The structures of intermediate dendrons were confirmed by IR, NMR (1H, 13C and 31P), LC-Mass and C, H, N analysis. The structure of the final dendron (5) was confirmed by IR, NMR (1H, 13C and 31P), MALDI-TOF-MS, and C, H, N analysis. The thermal stability of the resulting functionalized dendron has been checked by TGA/DTA analysis. The surface topography observed by scanning electronic microscopic study (SEM) gives the reminiscent of the dendritic structure.