Synthesis of Thioglycosides from Propargyl Glycosides Exploiting Alkynophilic Gold Catalyst

Various thioglycosides were synthesized from stable propargyl glycosides using catalytic quantity of AuBr₃ and various thiol aglycons. The current protocol enables preparation of thioglycosides from propargyl glycosides in an efficient and simple manner. The reaction is fast, catalytic, and mild. Supplemental materials are available for this article. Go to the publisher's online edition of Journal of Carbohydrate Chemistry to view the free supplemental file.     

Cycloaddition Approach for the Synthesis of Some Hindered N-Benzoylimidazoles

Cycloaddition of N-Benzoyl-4,5-diphenyl-2-strylimidazole to 2,5-dimethyl-3,4-diphenylcyclopentadienone, tetraphenylcyclopentadienone, 1,3-diphenylisobenzofuran and tetraphenylcyclopentadiene afforded the substituted and hindered imidazoles 2a,2b,2c & 2d. The N-benzoyl styrylimidazole 4 derived from phenanthrenequinone, cinnamaldehyde and ammonium acetate also underwent similar cycloaddition.     

A Novel Route to the Synthesis of 3-Pyridine Carboxaldehydes by Vilsmeier Reagent

2-Chloro-5-aryl-3-pyridine carboxaldehydes are obtained by Vilsmeier reaction of 4-aryl-3-buten-2-one oxime. The suspected intermediate N-(2-arylethenyl)acetamides also give the same 2-chloro-5-aryl-3-pyridine carboxaldehydes under identical reaction condition.     

Analysis of vibrational spectra of nano-bio molecules： Application to metalloporphrins

In this paper, we have applied the Lie algebraic model to nano-bio molecules to determine the vibrational spectra of different stretching and bending vibrational modes. The determined vibrational energy levels by the Lie algebraic model are compared with the experimental data. The results from the theoretical mode[ are consistent with the experimental data. The vibrational energy levels are clustering in the excited states.     

Optical switching,photophysical, and electrochemical behaviors of pendant triazole‐linked indolylfulgimide polymer

Triazole‐linked 2‐indolylfulgimide polymer has been synthesized and its photochromic switching behavior has been characterized by NMR, IR, GPC, TGA, DSC, and UV–Vis spectroscopy. The synthesized photochromic polymer showed absorption peak maxima at 386 and 510 nm wherein the absorption at 510 nm was attributed to charge transfer from triazole ring nitrogen to carbonyl carbon of fulgimide unit. Fluorescence lifetime studies on exciting at 550 nm reveals triexponential behavior with fluorescence decay around 0.1, 1 and 4.2 ns, which correspond to open (E), closed (C) form of fulgimide and triazole ring, respectively. Whereas exciting at 470 nm evidences biexponential fit with fluorescence decay around 0.1 and 2.2 ns, which corresponds to the closed (C) form and triazole ring, respectively. Fluorescence decay of triazole ring was found to be influenced by the excitation wavelength. The cyclic voltammogram of open form of polymer depicts irreversible reductive wave at ?1.4 V. On illumination with 360‐nm light, the reduction wave of polymer was shifted toward less cathodic wave at ?0.9 V; this leads to formation of the closed form of fulgimide unit. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis of novel 3-bromo-1,2-dihydroquinolines via palladium mediated intramolecular cyclization of N-tosyl-N-propargyl anilines

Facile synthesis of novel 3-bromo-1,2-dihydroquinolines by the intramolecular cyclization of N-tosyl-N-propargyl anilines catalyzed by Pd(OAc)₂ in conjunction with CuBr₂ and LiBr.