2024 Volume 7 Issues 1–3

Open Access

INEOS OPEN, 2024, 7 (1–3), 81–82  Journal of Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences Download PDF Electronic supplementary information DOI: 10.32931/io2434a

Search for New Approaches to Janus Dendrimers Based on Natural Compounds

Abstract

Dendrons with propargyl and hydroxy functional groups were obtained from vanillin and commercially available reagents. The fundamental possibility of the production of Janus dendrimers based on the resulting structure and earlier synthesized carbosilane dendrons by the azide–alkyne cycloaddition was demonstrated.

Key words: hybrid dendrimers, Janus dendrimers, natural compounds.

 

Introduction

Janus dendrimers are unique compounds consisting of several different dendrimer parts that differ in the terminal groups [1]. New applications of Janus dendrimers are associated with their capacity for self-assembly [2] and increased solubility [3]. Janus dendrimers are used in such areas as ionic liquids [4], hydrogels [5], and targeted drug delivery systems [6].

The self-assembly can be controlled by various non-covalent interactions between the amphiphilic parts of the Janus dendrimer. The main forces controlling the self-assembly of amphiphilic molecules are the formation of hydrogen bonds and the hydrophobic effect. In addition, depending on the structure of the Janus dendrimer, electrostatic forces, van der Waals and π-π interactions can play a significant role. The most important point is that, depending on the molecular structure, Janus dendrimers can self-organize into completely different nanoscale structures.

Today, the development of methods for obtaining Janus dendrimers from available raw materials is one of the most important fields for the practical application of dendrimers. In this report, we suggest a method for the synthesis of dendrimers based on the available natural raw material, namely, vanillin.

Results and discussion

It should be noted that only commercially available reagents were used at all stages of the synthesis of dendrimers, and the isolation of products at all stages was carried out using the simplest and cheapest methods (precipitation of the product followed by the filtration). In addition, none of the synthesis stages required expensive and complicated purification methods, leading to the product loss, which are typical for dendrimers (preparative gel permeation, column chromatography).

At the first stage, compound 1 was obtained in an acceptable yield (40%) from vanillin and commercially available epichlorohydrin, produced on a large scale (Scheme 1). Then the oxidation of compound 1 with hydrogen peroxide afforded acid 2 in high yield (95%), which was quantitatively converted to dipropargyl ester 3.

Scheme 1. Synthesis of the branching centers based on vanillin.

At the next stage, the resulting vanillin dendron was used to obtain two carbosilane dendrimers with hydrophilic and hydrophobic substituents by the azide–alkyne cycloaddition (Schemes 2, 3).

Scheme 2. Synthesis of hydrophobic carbosilane Janus dendrimers based on the vanillin branching center.

Scheme 3. Synthesis of hydrophilic carbosilane Janus dendrimers based on the vanillin branching center.

Conclusions

Hence, the synthetic route to dendrons based on a natural compound, namely, vanillin was developed. The principal possibility of application of this compound for creating Janus dendrimers of various types using the azide–alkyne cycloaddition was demonstrated. The simplicity of the reaction, complete conversion, and the absence of by-products make this approach a promising method for the production of Janus dendrimers. The remaining functional group at the focal point of the dendrimer will be used to obtain various modifications of Janus dendrimers based on vanillin.

Acknowledgements

This work was supported by the Russian Science Foundation (project no. 22-13-00459).

Electronic supplementary information

Electronic supplementary (ESI) information available online: the experimental details, NMR spectra, and GPC curves. For ESI, see DOI: 10.32931/io2434a.

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