Increasing demand for new chemical entities required efficient synthetic strategies for creating molecules with skeletal complexity including stereochemical diversity. Since structural variation of carbohydrates and the high density of functional groups offer scopes for modification, Pathak combined the high reactivity of vinyl sulfone (or selenone) with the in-built diversities of furanosides, pyranosides or functionalized acyclic structures derived from carbohydrates. Further synthetic manipulations afforded aminosugars, branched sugars, cyclopropanated carbohydrates and enantimerically pure densely functionalized carbocycles and heterocycles. This research also opens up a new route for the utilization of biomass in synthetic chemistry. A selected group of new compounds found applications as spacers for hybrid molecules, ligands for metal complexation, building blocks for gels, and designed peptidomimetics whereas some others were shown to possess biological activities.
Pathak also developed synthetic methodologies for generating a wide range of sugar-modified nucleosides, namely, aminonucleosides, vinyl sulfone-modified nucleosides, S,S-dioxidethiazine nucleosides, hexopyranosyl nucleosides, isonucleosides and branched chain nucleosides as ring conformational changes impart greater complexity to the overall structure. The biological applications of modified nucleosides were extended further to inhibit ribonuclease A, a model enzyme used in the development of inhibitors of other ribonucleases including angiogenin, implicated in the growth of solid tumors. The study continues to generate a wide variety of inhibitors and new information on the structural features of these enzymes.
FIST Program (level - II) Department of Science and Technology(DST)
Area of Research: Interface between cancer and regeneration
Area of Research: Inhibition of ribonucleases with synthetic carbohydrates
Area of Research: Synthesis and properties of functionalized triazoles
Area of Research: Vinyl nitro-modified carbohydrates
Area of Research: Inhibition of ribonucleases with synthetic nucleosides
Area of Research: Synthesis of heterocycles as new chemical entities
Area of Research: biologically relevant triazoles
Area of Research: Heterocyclic chemistry