Synthesis of new cyclitol compounds that influence the activity of phosphatidylinositol 4-kinase isoform, PI4K230

Synthesis of 1,4-dihydropyridines under solvent free conditions and investigation of their photo physical properties

Synthesis of five 4-aryl substituted 1,4-dihydropyridines was developed following condensation of multi component reaction strategy using yttrium triflate as a catalyst. The absorption and fluorescence properties of structurally related 4-aryl 1,4-dihydropyridines in different solvents of varied polarities was investigated. The absorption maxima of these compounds follow no order of solvent polarity and nature of substitution. The spectral characteristics are solvent and compound specific. Fluorophores with electron withdrawing group have larger fluorescence quantum yields and greater solvatochromism than the compounds with electron donating groups. Protic solvents yielded higher fluorescence quantum efficiency. The chemical shift of the proton attached to C-4 and the carbonyl stretching frequency of bis acetyl groups at 3 and 5-positions exhibited a linear relationship with Hammett's para substituent constants while no such relationship exists between the latter and electronic absorption maxima, fluorescence emission maxima, fluorescence quantum efficiency and Stokes shift.

Stereodivergent Syntheses of Conduramines and Aminocyclitols

[reaction: see text] The diastereomers of 6-amino-cyclohex-3-ene-1,2-diols 1 (4-deoxy-3-conduramines), key building blocks for the syntheses of a large range of natural products, have been enantioselectively prepared. Diastereoselective dihydroxylation of the compounds provided a new family of aminocyclitols 2 (deoxyinosamines). The key reactions of our syntheses are Sharpless catalytic asymmetric epoxidation, diastereoselective addition of vinylmetal reagents to the aldehydes, and ring-closing metathesis (RCM).