Flavonoid Constituents from Spiraea brahuica

Sparins A–C ( 1 – 3 , resp.), three new flavonoids, were isolated from the CHCl₃ subfraction of the EtOH extract of the whole plant of Spiraea brahuica, along with 3′,7‐di‐O‐methylquercetin ( 4 ) and luteolin 7‐β‐D ‐glucopyranoside ( 5 ), reported for the first time from this species. The structures of the new compounds were elucidated by spectroscopic techniques including MS and 2D‐NMR spectroscopy.     

Synthesis of of sterically encumbered biaryls based on a ‘copper(I)-catalyzed arylation/[3+3] cyclocondensation’ strategy

Sterically encumbered biaryls are prepared in two steps by combination of the CuI-proline-catalyzed arylation of acetylacetone with formal [3+3] cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-dienes. In addition, the synthesis of 4,6- and 5,6-diarylsalicylates based on [3+3] cyclizations is reported.     

Dengue blood analysis by Raman spectroscopy

In this work Raman spectra of normal and dengue infected serum and whole blood were analyzed. In normal whole blood and serum characteristic peaks were observed when excited at 442 and 532 nm. In dengue whole blood and serum all peaks found to be blue shifted with reduced Raman intensity. Dengue whole blood and serum shows two peaks at 1614 and 1750 cm^?1 which are due to presence of Immunoglobulin antibodies IgG and IgM. Whole study provides a route of information for diagnosis of dengue viral infection.     

Photonic Thermal Rectification with Composite Metamaterials

We demonstrate strong photonic thermal rectification effect between polar dielectrics plate and the composite metamaterials containing nonspherical polar dielectric nanoparticles with small volume fractions.Thermal rectification efficiency is found to be adjusted by the volume fractions and the nanoparticles’shape,and it can be as large as 80%when the polar dielectric nanoparticles are spherical in shape and are in the dilute limit with the volume fraction f=0.01.Physically,there exists strong electromagnetic coupling between the surface phonon polariton mode of polar dielectrics plate and the localized surface phonon polariton mode around polar dielectric nanoparticles.The results provide alternative new freedom for regulating energy flow and heat rectification efficiency in the near field,and may be helpful for design of multiparameter adjustable thermal diodes.     

Morphological,cytological and phytochemical studies in naturally occurring diploid and tetraploid populations of Physochlaina praealta from high altitudes of Trans-Himalaya

Physochlaina praealta samples were studied macromorphologically and cytomorphologically along with their detailed phytochemical investigation. The concentration of phytoconstituents showed a strong positive correlation with the ploidy level and altitudinal gradients. The total phenol content was detected maximum in the methanolic extract of leaves and stem of higher altitudinal plants in both cytotypes (2x, 4x). The maximum content of flavonoids was detected in the methanolic extract of root and leaves. Root organ from higher elevation possessed the highest DPPH radical scavenging activity, with the maximum percentage of inhibition being obtained in methanolic extracts. The plants of both cytotypes from higher elevations accumulate an abundant quantity of secondary metabolites. The two cytotypes differ from each other with respect to various morphometric characters thereby depicting the drastic affect of polyploidy.

     

Concise and Efficient Synthesis of Highly Potent and Selective Dipeptidyl Peptidase II Inhibitors

Highly potent and selective DPP II inhibitors N′‐(4‐Chlorobenzyl)‐N′‐methyl‐4‐oxo‐4‐(1‐piperidinyl)‐1,3‐(S)‐butane‐diamine dihydrochloride 1 and N′‐(4‐chlorobenzyl)‐4‐oxo‐4‐(1‐piperidinyl)‐1,3‐(S)‐butanediamine dihydrochloride 2 have been efficiently synthesized starting from L‐glutamine. A short and high yielding route with simple isolation techniques has been disclosed.