Indrapal Singh Aidhen

A new reagent for the synthesis of the α,β-unsaturated N-methoxy-N-methyl-amide structural unit has been developed. 2-(Benzo[d]thiazol-2-ylsulfonyl)-N-methoxy-N-methylacetamide, a crystalline solid with an indefinite shelf life that can be easily prepared in two convenient steps from 2-chloro-N-methoxy-N-methylacetamide, reacted with a variety of aldehydes under Julia conditions to furnish the α,β- unsaturated N-methoxy-N-methyl-amide functionality. © Wiley-VCH Verlag GmbH & Co. KGaA, 2006.

Two synthetic strategies have been developed for the synthesis of spaced sugars with lipophilic 1,4-phenylene core. A building block combining the usefulness of Weinreb amide functionality and modified Julia olefination reaction has been explored towards this objective. This building block offers complete flexibility in attaching any desired sugar derivative across phenylene spacer via C-C bond formation. The other strategy uses carbohydrate based building blocks for the synthesis of symmetrical as well as unsymmetrical 1,4-phenylene spaced sugars. This is the first report for the synthesis of 1,4-phenylene spaced sugars via C-C bond formation. © 2011 Elsevier Ltd. All rights reserved. 36.

Anovel synthetic strategy has been developed for the synthesis of spaced sugars with biphenyl as the lipophilic core. Towards this end, a new building block for the biphenyl-core has been developed based on sulfone chemistry. The building block, 4,4'-bis[(phenylsulfonyl)methyl]-l,l'-biphenyl undergoes convenient dialkylation with sugar-derived halides under basic conditions. Biphenyl-spaced cyclic and acyclic sugars have been synthesized successfully for the first time in the literature.

With the well-known precedence that N-methoxy-N-methyl amides are excellent acyl cation and aldehyde equivalents, N-methoxy-N-methyl-2- phenylsulfonylacetamide (3), a new reagent, synthetically equivalent to ΘCH2CHO and ΘCH2COR was synthesised. The simplicity involved in the alkylation at the active methylene site in 3, followed by safe removal of the phenylsulfonyl group, makes 3 a versatile reagent for two-carbon homologation of alkyl halides. The method, when applied to sugar halides 6j and 6k led to the synthesis of 2,3-dideoxy sugars.

The synthesis of (+)-varitriol (1) analogues was achieved through, the use of Julia olefination. The potential anticancer properties of 1 coupled with, our interest in developing building blocks that enable olefin formation under the Julia protocol constitute the basis of our research project. Efforts are aimed at the synthesis of building blocks 2 and 3 and to explore their use towards the synthesis of (+)-varit:riol analogues. Herein, we would, like to present the synthesis of building block 3 and its ability to react with variety of substituted aromatic-, heterocyclic- and carbohydrate-derived aldehydes to yield alkene 6 in moderate to good yields with E as the major isomer. The successful, coupling of 2 with (furanoside moieties) aldehydes 5k, 5m and 5n in particular and the obtainment of compound 23 reflect the promise associated with the new strategy. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.