CoMFA and CoMSIA of diverse pyrrolidine analogues as dipeptidyl peptidase IV inhibitors: active site requirements

The inhibition of dipeptidyl peptidase IV (DPP-IV) has emerged as an attractive target in the treatment of type 2 diabetes. In view of this development, a critical analysis of structural requirements of the DPP-IV inhibitors is envisioned to identify the significant features toward design of selective inhibitors. The comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) contour plots of pyrrolidine based analogues are used to analyze the structural requirements of a DPP-IV active site. The CoMFA model has shown a cross-validated q ² of 0.651 with a non-cross-validated r ² of 0.882 and explained 70.6% variance in the activity of external test compounds. In this, the steric and electrostatic fields have respectively contributed 59.8 and 40.2%, respectively, to the explained activity of the compounds. The CoMSIA model has shown optimum predictivity (cross-validated q ² = 0.661; non-cross-validated r ² = 0.803; external test set’s predictive r ² = 0.706) with four molecular fields namely, steric, electrostatic, hydrogen bond (HB)-donor, and HB-acceptor. The contour plots of molecular fields resulting from these studies have suggested: (i) steric restriction with small electron rich substituent at 2- and 3-position of pyrrolidine ring, (ii) presence of electropositive ring linker between the pyrrolidine head and aryl tail, (iii) presence of electron-rich groups around the aryl tail moiety, and (iv) presence of sulfonamide between the ring linker and aryl tail which would increase DPP-IV binding affinity of the compounds. These findings will help in the design of structurally related/new compounds as potential DPP-IV inhibitors.     

Facile one-pot solvothermal-assisted synthesis of uniform sphere-like Nb2O5 nanostructures for photocatalytic applications

Research on Chemical Intermediates - Preparation of semiconductor nanomaterials with controlled morphology and uniform porous surface is of great interest for enhanced photocatalytic applications....     

Synthesis, spectral studies, antimicrobial, antioxidant and insect antifeedant activities of some 9H-fluorene-2-yl keto-oxiranes

Thirteen ee (αS, βR) 9H-fluorene-2-yl keto-oxiranes (2-(9H)-fluorene-4-yl[3-(substituted phenyl)oxiran-2-yl]methanones) have been synthesized by phase transfer catalysed epoxidation of 9H-fluorene-2-yl chalcones. The yields of oxiranes are more than 95%. The synthesized oxiranes have been characterized by IR, (1)H, (13)C and GC-MS spectral data. The spectral data are correlated with Hammett substituent constants and Swain-Lupton parameters. From the regression analysis, the effect of substituents on the group frequencies has been predicted. The antimicrobial, antioxidant and insect antifeedant activities of all the synthesized oxiranes have been studied.     

IR and NMR spectral studies of 4-bromo-1-naphthyl chalcones-assessment of substituent effects

Infrared nuCO (cm(-1)) of s-cis and s-trans frequencies and nuclear magnetic resonance chemical shifts delta(1)H (ppm) of H-alpha and H-beta, delta(13)C (ppm) of C-alpha and C-beta data were assigned from their respective spectra of a series of various substituted styryl 4-bromo-1-naphthyl chalcones. These values are correlated with various Hammett substituent constants. From the results of statistical analysis, the effect of substituents can be explained.     

Synthesis and insect antifeedant activities of some substituted styryl 3,4-dichlorophenyl ketones

Sixteen substituted styryl 3,4-dichlorophenyl ketones [(2E)-1-(3,4-dichlorophenyl)-3-phenyl-2-propen-1-ones] were synthesized using eco-friendly benign stereoselective crossed-aldol reaction. They are characterized by their analytical, infrared, NMR and mass spectral data. The insect antifeedant activities of these chalcones were evaluated using Caster semilooper and Achoea janata L.