A short synthesis of carbohydrate derived N-benzyl aminocyclopentitols through N-O bond cleavage of the corresponding isoxazolidine derivatives: Evaluation of their anticancer properties using in vitro and in silico studies

A short synthesis of a potent glycosidase inhibitor N-benzyl-β-D-gluco aminocyclopentitol along with its 2-deoxy, and orthogonally protected 2-O-benzyl, 1,2,3-tri-O-benzyl and 1,2,3-tri-O-acetyl analogues through carbohydrate derived cyclopentane-fused isoxazolidine derivatives has been described herein. The key steps involve NaI mediated vinylation of d-glucose derived 5,6-di-O-mesylated compounds in sealed tube to produce 5,6-dideoxy-l,2-O-isopropylidene-α-D-xylo-hexo-5-enofuranos derivatives in very good yields. Subsequent acetonide deprotection and stereoselective intramolecular nitrone cycloaddition (INC) reaction involving C-4-vinyl functionalities and the latent aldehyde moiety at C-1 yielded various cyclopentano-isoxazolidines. The N-O bond cleavage of the isoxazolidine rings produced the targeted aminocyclopentitols. In vitro anticancer activities of the isoxazolidines and N-benzyl aminocyclopentitols were performed and found only 1,2,3-tri-O-benzyl analogue (20c) of N-benzyl-β-D-gluco aminocyclopentitols emerged as potent anticancer agent with IC50 value 54.90 μM. Furthermore, the molecular docking study confirmed that 20c, compared with the other derivatives, scores higher binding affinity for all the targeted receptors, HSP90, PLK1, and TOP2A.

The Petasis Reaction: Applications and Organic Synthesis-A Comprehensive Review

The Petasis reaction has introduced significant advancements through the use of various catalysts, solvents, methodologies, and substrates in diverse areas of chemistry, including medicinal, organic, combinatorial, biochemical, and heterocyclic chemistry. It is a prominent method for synthesizing compounds such as α-amino acids, β-amino alcohols, Aza-beta-lactams, alkylaminophenols, α-arylglycines, 2H-chromenes, aminophenols, and hydrazide alcohols. With the increasing demand for medicines, drugs, industrial products, insecticides, and pesticides, the Petasis reaction has become an indispensable and versatile tool. This review explores the range of reaction components, key mechanisms, and reaction conditions associated with the Petasis reaction. Additionally, the paper delves into the potential future directions of this reaction and highlights its various applications.

Strategies for the Development of Asymmetric and Non-Directed Petasis Reactions

The Petasis reaction is a multicomponent reaction of aldehydes, amines and organoboron reagents and is a useful method for the construction of substituted amines. Despite the significant advancement of the Petasis reaction since its invention in 1993, strategies for asymmetric and non-directed Petasis reactions remain limited. To date, there are very few catalytic asymmetric Petasis reactions and almost all asymmetric reports employ a chiral auxiliary. Likewise, the aldehyde component often requires a directing group, ultimately limiting the reaction's scope. In this Concept, key methods for asymmetric and non-directed Petasis reactions are discussed, focusing on how these conceptual advances can be applied to solve long-standing gaps in the Petasis literature.

Sugars in Multicomponent Reactions: A Toolbox for Diversity-Oriented Synthesis

Multicomponent reactions (MCRs) cover strategically employed chemical transformations that incorporate three or more reactants in one pot leading to a functionalized final product. Thus, it is an ideal tool to achieve high levels of complexity, diversity, yields of desired products, atom economy, and reduced reaction times. Sugars belong to the class of naturally occurring compounds with fascinating applications in the field of drug discovery due to the presence of various hydroxy groups and well-defined stereochemistry. However, their potential in MCRs has been realized only recently. This account describes recent advances in the synthesis of sugar-derived heterocycles synthesized by MCRs. We hope to encourage the synthetic and medicinal chemistry community to apply this powerful MCR chemistry to generate novel glycoconjugate challenges.

1 Introduction

2 Synthesis of Various Functionalized Sugar Compounds

2.1 Passerini and Ugi Multicomponent Reactions

2.2 Petasis Reaction

2.3 Hantzsch Reaction

2.4 Domino Ferrier–Povarov Reaction

2.5 Marckwald Reaction

2.6 Groebke–Blackburn–Bienaymé (GBB) Reaction

2.7 Prins–Ritter Reaction

2.8 Debus–Radziszewski Imidazole Synthesis Reaction

2.9 Mannich Reaction

2.10 A3-Coupling Reaction

2.11 [3+2]-Cycloaddition Reactions

2.12 Miscellaneous Reactions

3 Conclusion

Diastereo- and regioselective petasis aryl and allyl boration of ninhydrins towards synthesis of functionalized indene-diones and dihydrobenzoindeno-oxazin-ones

Petasis aryl and allyl borations were accomplished using substituted ninhydrins, boronic acids or 2-allyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane and 1,2-aminophenols in Hexafluoroisopropanol (HFIP) without any catalysts to synthesize different aryl and allyl derivatives of ninhydrins. The nature of substitution in the boronic acids and 1,2-amino phenols was the key factor in determining the diastereo-regioselectivity and the type of product distributions. The products were isolated and characterized by HMBC, HSQC, ¹H, ¹³C NMR experiments and X-ray single crystallographic analysis. A probable reaction pathway involves in situ formation of acyclic and cyclic ninhydrin-amino alcohol adducts, with the positioned hydroxyl group determining the stereo-regioselective outcome via tetracoordinated boron intermediates. A metal free diastereo- and regioselective Petasis aryl and allyl boration of ninhydrins.

Multicomponent Petasis Reaction for the Synthesis of Functionalized 2-Aminothiophenes and Thienodiazepines

Multicomponent Petasis reaction has been widely applied for the synthesis of functionalized amine building blocks and biologically active compounds. Employing primary aromatic amines that are not typical reactive substrates contributes to expand the application scope of the Petasis reaction. In this study, we demonstrated the synthesis of functionalized 2-aminothiophenes using Gewald-reaction-derived 2-aminothiophenes as the amine substrates, whose low reactivity in the Petasis reaction was overcome using hexafluoro-2-propanol as the solvent in a mild condition. The obtained Petasis products are amenable for further transformations owing to the presence of multiple functional handles. A following intramolecular cyclization of selected Petasis products afforded substituted tricyclic heterocycles that incorporate a pharmaceutically interesting thienodiazepine moiety.