Stereoselective synthesis of substituted 1,2-annulated sugars by domino double-Michael addition reaction.

A simple, highly stereoselective one-pot methodology for the synthesis of novel 1,2-annulated sugars comprising of oxa-oxa and oxa-carbasugar fused skeletons from 2-nitrogalactal and a sugar-derived enone, obtained from 2-formylgalactal, promoted by KOBu and CHONa respectively is described. Both processes rely on a domino double-Michael addition reaction resulting in the formation of three stereocenters in a single pot, including a quaternary center.

Stereoselective synthesis of 1,2-annulated-C-Aryl glycosides from carbohydrate-derived terminally unsubstituted dienes and arynes: Application towards synthesis of sugar-fused- or branched- naphthalenes, and C-Aryl glycosides.

Synthesis of 1,2-annulated-C-aryl glycosides has been achieved in a stereoselective manner through the Diels-Alder reaction between carbohydrate-derived terminally unsubstituted dienes and in situ generated arynes. In these reactions, formation of sugar-fused (or branched) naphthalenes was also observed and found to be temperature dependent and thus constituting one of the salient features of this work. The synthetic importance of 1,2-annulated-C-aryl glycosides has been explored by transforming them into densely oxygenated products by functionalizing the unsubstituted exo-double bond.

Synthesis of sugar-derived spiroaminals via lactamization and metathesis reactions.

A series of sugar-derived spiroaminals has been synthesized by utilizing cross metathesis, ring closing metathesis and lactamization reactions as key steps from 1-C-alkylated glycosyl azides and important correlations in the spectral data between spiroaminals and their respective anomers are reported.

Rapid, one-pot derivatization and distillation of chlorophenols from solid samples with their on-line enrichment.

A microwave-assisted steam distillation (MASD) sample preparation technique for extracting chlorophenols from solid samples was studied. This open vessel microwave system based study developed as an integrated method since it has incorporated extractive distillation, derivatization and on-line enrichment. Gas chromatography (GC) with electron-capture detection was used for the analysis.

Focused microwave aqueous extraction of chlorophenols from solid matrices and their analysis by chromatographic techniques.

Open-vessel focused microwave (FMW) extraction with a purely aqueous carbonate solution was used for the extraction of chlorophenols from various solid matrices. After SPE on C18-bonded silica, the analytes were determined as such by LC-UV or, as their acetyl derivatives, by GC-ECD. The FMW aqueous extraction is efficient and rapid and no organic solvents are used.