Mesitylene‐Cored Glucoside Amphiphiles (MGAs) for Membrane Protein Studies: Importance of Alkyl Chain Density in Detergent Efficacy

Detergents serve as useful tools for membrane protein structural and functional studies. Their amphipathic nature allows detergents to associate with the hydrophobic regions of membrane proteins whilst maintaining the proteins in aqueous solution. However, widely used conventional detergents are limited in their ability to maintain the structural integrity of membrane proteins and thus there are major efforts underway to develop novel agents with improved properties. We prepared mesitylene‐cored glucoside amphiphiles (MGAs) with three alkyl chains and compared these agents with previously developed xylene‐linked maltoside agents (XMAs) with two alkyl chains and a conventional detergent (DDM). When these agents were evaluated for four membrane proteins including a G protein‐coupled receptor (GPCR), some agents such as MGA‐C13 and MGA‐C14 resulted in markedly enhanced stability of membrane proteins compared to both DDM and the XMAs. This favourable behaviour is due likely to the increased hydrophobic density provided by the extra alkyl chain. Thus, this study not only describes new glucoside agents with potential for membrane protein research, but also introduces a new detergent design principle for future development.     

σ versus π-radical: Tuning the electronic nature of neutral carbon (I) compounds with three non-bonding electrons

The bonding and reactivity of the hypo-coordinated compounds with one, two, and four non-bonding electrons namely, carbon-centered free radical, carbenes, and carbones were well earlier established. Here, we report stability, bonding and reactivity of compounds RCL, where R is one-electron donor group (R =  CH₃ ( a ),  CHO ( b ), and  NO₂ ( c )) and L is two-electron donor ligand (L = cAAC ( 1 ), CO ( 2 ), NHC ( 3 ) and PMe₃ ( 4 )), having three non-bonding electrons. The ground states of molecules exist in a doublet with a lone pair of electrons and an unpaired electron at the central carbon atom (C1). The spin hops over from π- to σ-type orbitals is observed as the π-acceptor strength of the donor ligand increases. The replacement of the methyl group by  CHO and  NO₂ indicate that the cAAC and  CHO substituted compounds gives a σ-radical except in compound 2c . These molecules show very high proton affinity and exothermic reaction energy for the hydrogen atom addition indicating dual reactivity namely, radical and lone pair reactivity.     

Ultrasensitive second-harmonic generation frequency-resolved optical gating by aperiodically poled LiNbO3 waveguides at 1.5 microm

We retrieve intensity and phase profiles of 280 fs, 50 MHz optical pulses with 124 aJ coupled pulse energy (960 photons) by second-harmonic generation (SHG) frequency-resolved optical gating, using aperiodically poled LiNbO3 waveguides. The strong nonlinear interaction that is due to confinement within the micrometer-sized waveguide structure and the linearly chirped poling period contribute, respectively, to high SHG efficiency and broad phase-matching bandwidth. The achieved sensitivity is 2.7 x 10(-6) mW2, improving on the previous record for self-referenced complete pulse characterization by 5 orders of magnitude.     

A Facile Synthesis of 5‐Phenyl‐Dibenzo[b,g][1,8]Napthyridines

The Vilsmeier Haack heterocyclization of 2‐aryl amino‐4‐phenyl quinolines quinoline yielded the hitherto unknown 5‐phenyl‐dibenzo[b,g][1,8]naphthyridines in quantitative yield. The synthesis of aryl amines was achieved by the action of anilines on 2‐chloro‐4‐phenyl quinoline, which in turn was sourced through the combes reaction of benzoyl acetanilides.     

Novel one pot synthesis of 2-amino-4-chloroquinolines via Smiles rearrangement

We have developed a novel one pot synthesis of 4-chloroquinolin-2-ylamines via Smiles rearrangement under milder condition. The key transformation involves O-alkylation of 4-chloro-1H-quinolin-2-ones with chloroacetamide followed by Smiles rearrangement. The scope of this methodology is further extended to the synthesis of 4-chloroquinolin-2-ylmethylamines and 2-(4-chloroquinolin-2-ylamino)ethanols. This methodology has furnished good yields of 2-amino-4-chloroquinolines.     

Chromatographic Analysis of Bioactive Markers in Vidangarista,an Ayurvedic Polyherbal Formulation

JPC – Journal of Planar Chromatography – Modern TLC - Vidangarista is an ayurvedic polyherbal formulation officially recorded in the Ayurvedic formulary of India and used as an...