S_NAr Isocyanide Diversification

Isocyanides are important building blocks in organic synthesis; however, their synthesis is time and resource consuming and often unpleasant due to their smelly nature. Diversification of isocyanides can be accomplished by de novo synthesis or from already existing isocyanides. In this work, we report for the first-time isocyanide diversification based on nucleophilic aromatic substitution of suitable precursor isocyanides. The mild conditions allow for easy access to multiple novel isocyanides useful in organic synthesis. The resulting isocyanides are solid and non-noxious, yet react nicely in multicomponent reactions

Highly Stereoselective Ugi/Pictet-Spengler Sequence

Discovering novel synthetic routes for rigid nitrogen-containing polyheterocycles using sustainable, atom-economical, and efficient (= short) synthetic pathways is of high interest in organic chemistry. Here, we describe an operationally simple and short synthesis of the privileged scaffold dihydropyrrolo[1,2-a]pyrazine-dione from readily accessible starting materials. The alkaloid-type polycyclic scaffold with potential bioactivity was achieved by a multicomponent reaction (MCR)-based protocol via a Ugi four-component reaction and Pictet-Spengler sequence under different conditions, yielding a diverse library of products

Low-coordinate erbium(III) single-molecule magnets with photochromic behavior

[Image: see text] The structures and magnetic properties of photoresponsive magnets can be controlled or fine-tuned by visible light irradiation, which makes them appealing as candidates for ternary memory devices: photochromic and photomagnetic at the same time. One of the strategies for photoresponsive magnetic systems is the use of photochromic/photoswitchable molecules coordinated to paramagnetic metal centers to indirectly influence their magnetic properties. Herein, we present two erbium(III)-based coordination systems: a trinuclear molecule {[Er(III)(BHT)(3)](3)(dtepy)(2)}(.)4C(5)H(12) (1) and a 1D coordination chain {[Er(III)(BHT)(3)(azopy)}(n)·2C(5)H(12) (2), where the bridging photochromic ligands belong to the class of diarylethenes: 1,2-bis((2-methyl-5-pyridyl)thie-3-yl)perfluorocyclopentene (dtepy) and 4,4′-azopyridine (azopy), respectively (BHT = 2,6-di-tert-butyl-4-methylphenolate). Both compounds show slow dynamics of magnetization, typical for single-molecule magnets (SMMs) as revealed by alternating current (AC) magnetic susceptibility measurements. The trinuclear compound 1 also shows an immediate color change from yellow to dark blue in response to near-UV irradiation. Such behavior is typical for the photoisomerization of the open form of the ligand into its closed form. The color change can be reversed by exposing the closed form to visible light. The chain-like compound 2, on the other hand, does not show significant signs of the expected trans–cis photoisomerization of the azopyridine in response to UV irradiation and does not appear to show photoswitching behavior

Author Correction: The isocyanide SN2 reaction

In this article the author name Katarzyna Kurpiewska was incorrectly written as Katarzyna Kurpiewsk. The original article has been corrected.</p

Ammonia-promoted one-pot tetrazolopiperidinone synthesis by Ugi reaction

Ammonia in the tetrazole Ugi variation together with α-amino acid methyl ester-derived isocyanides provides tetrazolopiperidinones in good to high yields in one pot. The scope and limitations of this reaction were investigated by performing >70 reactions. The scaffold is useful to fill high-throughput screening decks and in structure-based drug design

Amenamevir by Ugi-4CR

We report a concise, convenient and sustainable synthesis of the approved anti-herpes zoster drug, Amenamevir. Based on the Ugi-4CR, our approach can access Amenamevir by a simple, rapid and one-pot synthesis. Compared to other reported syntheses, ours is more sustainable, shorter, and higher yielding. The X-ray crystal structures of key intermediate 3-(4-isocyanophenyl)-1,2,4-oxadiazole 4 and Amenamevir are reported for the first time. Computational retrosynthesis of Amenamevir using four popular freeware could recapitulate the described multi-step approaches but disappointingly did not propose our one-pot synthesis

Synthesis of Tunable Fluorescent Imidazole-Fused Heterocycle Dimers

A short, concise, and one-pot synthesis of imidazo-fused heterocycle dimers with tunable fluorescent properties has been developed. By the first time use of glyoxal dimethyl acetal in the Groebke-Blackburn-Bienaymé (GBB) three-component reaction (3CR), the innovation features a new series of fluorescence-tunable imidazo-fused heterocycle dimers exhibiting a broad substrate scope with good yields. Luminescence studies demonstrate that these GBB-dimers possess color-tunable properties, and their emission colors can be successively changed from blue to green and yellow by easy substituent control

Correction: Amenamevir by Ugi-4CR

The authors regret that there was an inaccuracy present in the affiliation information for one of the authors, Alexander Dömling, in the original manuscript. The work was performed at the Department of Drug Design, University of Groningen, Groningen, The Netherlands ([email protected]) before the transition of Alexander Dömling to their current institution, CATRIN, Innovative Chemistry Group, Palacký University Olomouc, Olomouc, Czech Republic ([email protected]). The corrected list of author information and affiliations for this article is as shown here. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.</p

N-Edited Guanine Isosteres

Guanine is one out of five endogenous nucleobases and of key interest in drug discovery and chemical biology. Hitherto, the synthesis of guanine derivatives involves lengthy multistep sequential synthesis of low overall diversity, resulting in the quest for innovation. Using a “single-atom skeletal editing” approach, we designed 2-aminoimidazo[2,1-f][1,2,4]triazin-4(3H)-one as a guanine isostere, conserving the biologically important HBA-HBD-HBD (HBA = hydrogen bond acceptor; HBD = hydrogen bond donor) substructure. We realized our design by a simple one-pot two-step method combining the Groebke-Blackburn-Bienaymé reaction (GBB-3CR) and a deprotection reaction to assemble the innovative guanine isosteres in moderate to good yields. Our innovative, diverse, short, and reliable multicomponent reaction synthesis will add to the toolbox of guanine isostere syntheses.</p

Fourfold symmetric MCR's via the tetraisocyanide 1,3-diisocyano-2,2-bis(isocyanomethyl)propane

Oligoisocyanides are attractive synthetic targets, however, only a few are known. Here, we describe the smallest stable tetraisocyanide possible, the 1,3-diisocyano-2,2-bis(isocyano-methyl)propane (1) with S4 symmetry. Its four-step synthesis, structure, and reactivity in unprecedented symmetric fourfold Ugi 4CR and fourfold Passerini 3CR are described. Exhibiting high functional group tolerance and moderate to high yields, we foresee multiple applications of 1,3-diisocyano-2,2-bis(isocyanomethyl)propane, for example in MOFs, COFs, dendrimers, or artificial organs