Reaction of amide bonds in t-butyldimethylsilyl-protected inosine, 2′-deoxyinosine, guanosine, 2′-deoxyguanosine, and 2-phenylinosine with commercially available peptide-coupling agents (benzotriazol-1H-yloxy)tris(dimethylaminophosphonium) hexafluorophosphate (BOP), (6-chloro-benzotriazol-1H-yloxy)trispyrrolidinophosphonium hexafluorophosphate (PyClocK), and (7-azabenzotriazol-1H-yloxy)trispyrrolidinophosphonium hexafluorophospate (PyAOP) gave the corresponding O6-(benzotriazol-1-yl) nucleoside analogues containing a C–O–N bond. Upon exposure to bis(pinacolato)diboron and base, the O6-(benzotriazol-1-yl) and O6-(6-chlorobenzotriazol-1-yl) purine nucleoside derivatives obtained from BOP and PyClocK, respectively, underwent N–O bond reduction and C–N bond formation, leading to the corresponding C6 benzotriazolyl purine nucleoside analogues. In contrast, the 7-azabenzotriazolyloxy purine nucleoside derivatives did not undergo efficient deoxygenation, but gave unsymmetrical nucleoside dimers instead. This is consistent with a prior report on the slow reduction of 1-hydroxy-1H-4-aza and 1-hydroxy-1H-7-azabenzotriazoles. Because of the limited number of commercial benzotriazole-based peptide coupling agents, and to show applicability of the method when such coupling agents are unavailable, 1-hydroxy-1H-5,6-dichlorobenzotriazole was synthesized. Using this compound, silyl-protected inosine and 2′-deoxyinosine were converted to the O6-(5,6-dichlorobenzotriazol-1-yl) derivatives via in situ amide activation with PyBroP. The O6-(5,6-dichlorobenzotriazol-1-yl) purine nucleosides so obtained also underwent smooth reduction to afford the corresponding C6 5,6-dichlorobenzotriazolyl purine nucleoside derivatives. A total of 13 examples were studied with successful reactions occurring in 11 cases (the azabenzotriazole derivatives, mentioned above, being the only unreactive entities). To understand whether these reactions are intra or intermolecular processes, a crossover experiment was conducted. The results of this experiment as well as those from reactions conducted in the absence of bis(pinacolato)diboron and in the presence of water indicate that detachment of the benzotriazoloxy group from the nucleoside likely occurs, followed by reduction, and reattachment of the ensuing benzotriazole, leading to products.

In the present study, SrTiO 3 (STO) was synthesized using oxalate method. A series of V 2 O 5 nanoparticles supported on SrTiO 3 (V 2 O 5 / STO) with the vanadia content ranging from 0.5 to 2 wt. % was synthesized by wet impregnation method. Physicochemical properties of the synthesized catalysts were determined by X-ray diffraction, Fourier transform infrared spectroscopy, Transmission electron microscopy, N 2 physisorption and X-ray photoelectron spectroscopy and acidity by pyridine adsorption method. XPS studies of the catalysts reveal that vanadium is in + 5 oxidation state. Particle size of the catalysts calculated from TEM image analysis was found to be in the range of 86-92 nm. Pyridine adsorption studies reveals presence of Lewis acidity in the catalysts and the number of Lewis acid sites increase with vanadium content of the catalysts. Their catalytic activity was evaluated for the liquid phase oxidation of benzyl alcohol to benzaldehyde. STO is found to be least active and highly selective for the formation of benzaldehyde product where as V 2 O 5 /STO catalysts were found to be highly active and selective for the oxidation of benzyl alcohol reaction. Among all the catalysts the one with 1 wt. % loading of vanadia contains a greater number of active sites is found to be highly efficient heterogeneous catalyst system for selective oxidation of benzyl alcohol with 100 % benzaldehyde selectivity. The catalytic activity of the catalysts was correlated with the physico-chemical properties of the catalysts.

Reaction of alkenes and alkenols with N-iodosuccinimide (NIS) and benzenesulfinic acid in dichloromethane at room temperature affords vic-iodophenylsulfonyl adducts in good to high yields. Treatment of the iodosulfones with neutral alumina in dichloromethane at room temperature results in dehydroiodination to give the corresponding vinyl sulfones in high yield and purity by this convenient two-step procedure. Application of the iodosulfonation–dehydroiodination sequence to allylic alcohols and silyl ethers gave γ-oxygenated, α,β-unsaturated phenylsulfones, while the attempted iodosulfonation of glycals, as intermediates to vinyl sulfones, resulted in addition of benzenesulfinic acid with double bond shift (Ferrier rearrangement). Key words: iodosulfonation, vinyl sulfones, benzenesulfinic acid, N-iodosuccinimide, dehydroiodination.

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