Insertion of an anthranilic acid in an amyloidogenic peptide sequence generates a novel conformationally restricted α/β-hybrid peptide that inhibits amyloid formation of Aβ(1-40) and disrupts preformed fibrillar aggregates in vitro. Such β-sheet breaker hybrid peptides (BSBHps) may be useful for designing novel physiologically important compounds relevant to diverse amyloidoses and for studying the process of aggregation.

Here we report the synthesis and utility of ethyl 2-(tert-butoxycarbonyloxyimino)-2-cyanoacetate (Boc-Oxyma) as an efficient coupling reagent for racemization-free esterification, thioesterification, amidation reactions and peptide synthesis that uses equimolar amounts of acids and alcohols, thiols, amines or amino acids, respectively. Its application to solid phase as well as solution phase peptide synthesis is also demonstrated and a mechanistic investigation is discussed. Boc-Oxyma is similar to the well known coupling agent COMU {1-[1-cyano-2-ethoxy-2-oxoethylideneaminooxy)-dimethylaminomorpholino]uronium hexafluorophosphate} in terms of its high reactivity and mechanism of action. However, it is not only much easier to prepare, but also to recover and reuse, thereby generating far less chemical waste.

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Reversion of protein or peptide aggregation is a formidable task, important in various domains of research at the interface of chemistry, medicine, and nanoscience. A novel class of dipeptides, termed as β-breaker dipeptides (BBDPs), is identified, which can be incorporated into the self-recognizing sequences to generate a novel class of conformational switch which forms β-sheet at an initial stage and then converts in a controlled manner to random coil at specific conditions. Incorporation of BBDPs in a well designed amyloidogenic peptides generates a special class of β-sheet breaker peptides those undergo a chemical change at physiological condition generating a breaker element in situ. These β-breaker peptides are shown to first incorporate into the amyloid and then disrupt it. Such conformational switches may be used to study agrregation/disaggregation process and may find many biomedical applications relevant to aggregation related disorders. Such strategy for reversion of peptide aggregation using chemical tricks may find application in material chemistry as well.

A milder and more efficient procedure for the synthesis of sulfonamides by activating sulfonic acid groups as the corresponding sulfonate esters of ethyl 2‐cyano‐2‐(hydroxyimino)acetate (Oxyma) is reported. This method is greener than all other existing protocols for the purpose. Other important advantages lie in (a) its applicability to less nucleophilic anilines under ambient and milder conditions and (b) its compatibility with solid phase peptide synthesis and acid‐labile groups such as trityl (Trt) and tBu, which empowers the solid phase synthesis of sulfonamides of various peptides. To illustrate this, the syntheses of three sulfonamide derivatives of the peptide GAILG‐NH2, which is relevant in the context of drug design against type 2 diabetes, are demonstrated by using Fmoc‐based solid‐phase peptide synthesis (SPPS).