Photoorganocatalysis, small organic molecules and light in the service of organic synthesis: the awakening of a sleeping giant

2018 ◽  
Vol 16 (25) ◽  
pp. 4596-4614 ◽  
Author(s):  
Ioanna K. Sideri ◽  
Errika Voutyritsa ◽  
Christoforos G. Kokotos

This review is focused on recent developments in the use of small organic molecules as photocatalysts.

2020 ◽  
Vol 16 ◽  
pp. 833-857 ◽  
Author(s):  
Maria A Theodoropoulou ◽  
Nikolaos F Nikitas ◽  
Christoforos G Kokotos

Photochemistry, the use of light to promote organic transformations, has been known for more than a century but only recently has revolutionized the way modern chemists are thinking. Except from transition metal-based complexes, small organic molecules have been introduced as catalysts or initiators. In this review, we summarize the potential that (aromatic or aliphatic) aldehydes have as photoinitiators. The photophysical properties and photoreactivity of benzaldehyde are initially provided, followed by applications of aldehydes as initiators for polymerization reactions. Finally, the applications to date regarding aldehydes as photoinitiators in organic synthesis are presented.


Author(s):  
Qiuqin Zhou ◽  
Annabelle Fülöp ◽  
Carsten Hopf

AbstractMatrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is a fast-growing technique for visualization of the spatial distribution of the small molecular and macromolecular biomolecules in tissue sections. Challenges in MALDI-MSI, such as poor sensitivity for some classes of molecules or limited specificity, for instance resulting from the presence of isobaric molecules or limited resolving power of the instrument, have encouraged the MSI scientific community to improve MALDI-MSI sample preparation workflows with innovations in chemistry. Recent developments of novel small organic MALDI matrices play a part in the improvement of image quality and the expansion of the application areas of MALDI-MSI. This includes rationally designed/synthesized as well as commercially available small organic molecules whose superior matrix properties in comparison with common matrices have only recently been discovered. Furthermore, on-tissue chemical derivatization (OTCD) processes get more focused attention, because of their advantages for localization of poorly ionizable metabolites and their‚ in several cases‚ more specific imaging of metabolites in tissue sections. This review will provide an overview about the latest developments of novel small organic matrices and on-tissue chemical derivatization reagents for MALDI-MSI.


2020 ◽  
Vol 07 ◽  
Author(s):  
Rajib Sarkar ◽  
Chhanda Mukhopadhyay

Abstract:: The use of small organic molecules as organocatalysts in organic synthesis has intensely studied over the past decade. In this emerging field, considerable study has led to the introduction of various efficient organocatalyzed synthetic methods of carbon-carbon and carbon-hetero atom bond formations. The use of these organocatalysts also emerged environmentally benign reaction conditions compared to the metal catalyzed transformations. In this review, we make a special attention on the most recent organocatalytic protocols reported for the synthesis of heterocycles. The works have been outlined by depending on the organocatalysts used as (i) nitrogen based molecules as organocatalyst, (ii) NHCs as organocatalyst, and (iii) phosphorus based molecules as organocatalyst. The discussion intends to reveal the scope as well as vitality of organocatalysis in the area of heterocycle synthesis.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1591
Author(s):  
Félix Gayraud ◽  
Merlin Klußmann ◽  
Ines Neundorf

This review summarizes recent developments in conjugation techniques for the synthesis of cell-penetrating peptide (CPP)–drug conjugates targeting cancer cells. We will focus on small organic molecules as well as metal complexes that were used as cytostatic payloads. Moreover, two principle ways of coupling chemistry will be discussed direct conjugation as well as the use of bifunctional linkers. While direct conjugation of the drug to the CPP is still popular, the use of bifunctional linkers seems to gain increasing attention as it offers more advantages related to the linker chemistry. Thus, three main categories of linkers will be highlighted, forming either disulfide acid-sensitive or stimuli-sensitive bonds. All techniques will be thoroughly discussed by their pros and cons with the aim to help the reader in the choice of the optimal conjugation technique that might be used for the synthesis of a given CPP–drug conjugate


Synthesis ◽  
2021 ◽  
Author(s):  
Daiki Doiuchi ◽  
Tatsuya Uchida

C–H bonds are ubiquitous and abundant in organic molecules. If such C–H bonds can be converted to the desired functional groups in a site-, chemo-, diastereo-, and enantio-selective manner, the functionalization of C–H bonds would be an efficient tool for the step-, atom- and redox-economic organic synthesis. C–H oxidation is one of a typical C–H functionalization, to afford hydroxy and carbonyl groups, which are essential key functional groups in organic synthesis and biological chemistry, directly. Recently, significant developments have been made using non-heme-type transition metal catalysts. Oxygen functional groups can be introduced to not only simple hydrocarbons but also complicated natural products. In this paper, the recent developments, during the last fourteen years, of non-heme-type complex-catalyzed C–H oxidations are reviewed.


2017 ◽  
Vol 13 ◽  
pp. 1907-1931 ◽  
Author(s):  
Tapas Kumar Achar ◽  
Anima Bose ◽  
Prasenjit Mal

With the growing interest in renewable energy and global warming, it is important to minimize the usage of hazardous chemicals in both academic and industrial research, elimination of waste, and possibly recycle them to obtain better results in greener fashion. The studies under the area of mechanochemistry which cover the grinding chemistry to ball milling, sonication, etc. are certainly of interest to the researchers working on the development of green methodologies. In this review, a collection of examples on recent developments in organic bond formation reactions like carbon–carbon (C–C), carbon–nitrogen (C–N), carbon–oxygen (C–O), carbon–halogen (C–X), etc. is documented. Mechanochemical syntheses of heterocyclic rings, multicomponent reactions and organometallic molecules including their catalytic applications are also highlighted.


2018 ◽  
Vol 90 (1) ◽  
pp. 157-165 ◽  
Author(s):  
Stefan B. Lawrenson

AbstractSolid-phase organic synthesis is an essential method for the rapid synthesis of complex biological structures and libraries of small organic molecules. However, it is often associated with the use of large quantities of problematic solvents for the removal of excess reagents and reaction by-products. Given that solvent will often be the biggest contributor to waste generated in the average pharmaceutical/fine-chemical process, its exchange for a more desirable alternative often presents the biggest gains in terms of reducing environmental impact. This review aims to explore recent approaches to performing solid-phase organic synthesis, and associated solid-phase peptide synthesis, in neoteric solvents and reaction media that present greener alternatives.


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