Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Unanticipated switch of reactivity of isonitrile via N≡C bond scission: Cascade formation of symmetrical sulfonyl guanidine.

ABSTRACT: Unanticipated formation of symmetrical sulfonyl guanidine was observed while treating isonitriles with N,N-dibromoarylsulfonamides in absence of an external amine source. Interesting feature of this work is that one molecule of isonitrile initially reacts with dibromoarylsulfonamide via the C-end to produce the intermediate carbodiimide while the other molecule undergoes C≡N triple bond cleavage to react as amine source with the intermediate. This switch of reactivity from C-center to N-center of the isonitrile generated symmetrical guanidine.

SUBMITTER: Mishra D

PROVIDER: S-EPMC10384224 | biostudies-literature | 2023 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Unanticipated switch of reactivity of isonitrile via N≡C bond scission: Cascade formation of symmetrical sulfonyl guanidine.

Mishra Debashish D Rajkhowa Sagarika S Phukan Prodeep P

iScience 20230703 8

Unanticipated formation of symmetrical sulfonyl guanidine was observed while treating isonitriles with <i>N,N</i>-dibromoarylsulfonamides in absence of an external amine source. Interesting feature of this work is that one molecule of isonitrile initially reacts with dibromoarylsulfonamide via the C-end to produce the intermediate carbodiimide while the other molecule undergoes C≡N triple bond cleavage to react as amine source with the intermediate. This switch of reactivity from C-center to N-c ...[more]

PMID: 37520733

Similar Datasets

Facile scission of isonitrile carbon-nitrogen triple bond using a diborane(4) reagent.

Project description:Transition metal reagents and catalysts are generally effective to cleave all three bonds (one σ and two π) in a triple bond despite its high bonding energy. Recently, chemistry of single-bond cleavage by using main-group element compounds is rapidly being developed in the absence of transition metals. However, the cleavage of a triple bond using non-transition-metal compounds is less explored. Here we report that an unsymmetrical diborane(4) compound could react with carbon monoxide and tert-butyl isonitrile at room temperature. In the latter case, the carbon-nitrogen triple bond was completely cleaved in the absence of transition metal as confirmed by X-ray crystallographic analysis, (13)C NMR spectroscopy with (13)C labelling and DFT calculations. The DFT calculations also revealed the detailed reaction mechanism and indicated that the key for the carbon-nitrogen triple-bond cleavage could be attributed to the presence of nucleophilic nitrogen atom in one of the intermediates.

| S-EPMC4083417 | biostudies-literature

Visible Light-Driven Cascade Carbon-Carbon Bond Scission for Organic Transformations and Plastics Recycling.

Project description:Significant efforts are devoted to developing artificial photosynthetic systems to produce fuels and chemicals in order to cope with the exacerbating energy and environmental crises in the world now. Nonetheless, the large-scale reactions that are the focus of the artificial photosynthesis community, such as water splitting, are thus far not economically viable, owing to the existing, cheaper alternatives to the gaseous hydrogen and oxygen products. As a potential substitute for water oxidation, here, a unique, visible light-driven oxygenation of carbon-carbon bonds for the selective transformation of 32 unactivated alcohols, mediated by a vanadium photocatalyst under ambient, atmospheric conditions is presented. Furthermore, since the initial alcohol products remain as substrates, an unprecedented photodriven cascade carbon-carbon bond cleavage of macromolecules can be performed. Accordingly, hydroxyl-terminated polymers such as polyethylene glycol, its block co-polymer with polycaprolactone, and even the non-biodegradable polyethylene can be repurposed into fuels and chemical feedstocks, such as formic acid and methyl formate. Thus, a distinctive approach is presented to integrate the benefits of photoredox catalysis into environmental remediation and artificial photosynthesis.

| S-EPMC6918108 | biostudies-literature

Sulfonyl Nitrene and Amidyl Radical: Structure and Reactivity.

Project description:Photocatalytic generation of nitrenes and radicals can be used to tune or even control their reactivity. Photocatalytic activation of sulfonyl azides leads to the elimination of N2 and the resulting reactive species initiate C-H activations and amide formation reactions. Here, we present reactive radicals that are generated from sulfonyl azides: sulfonyl nitrene radical anion, sulfonyl nitrene and sulfonyl amidyl radical, and test their gas phase reactivity in C-H activation reactions. The sulfonyl nitrene radical anion is the least reactive and its reactivity is governed by the proton coupled electron transfer mechanism. In contrast, sulfonyl nitrene and sulfonyl amidyl radicals react via hydrogen atom transfer pathways. These reactivities and detailed characterization of the radicals with vibrational spectroscopy and with DFT calculations provide information necessary for taking control over the reactivity of these intermediates.

| S-EPMC9323475 | biostudies-literature

Multicolor Mechanofluorophores for the Quantitative Detection of Covalent Bond Scission in Polymers.

Project description:The fracture of polymer materials is a multiscale process starting with the scission of a single molecular bond advancing to a site of failure within the bulk. Quantifying the bonds broken during this process remains a big challenge yet would help to understand the distribution and dissipation of macroscopic mechanical energy. We here show the design and synthesis of fluorogenic molecular optical force probes (mechanofluorophores) covering the entire visible spectrum in both absorption and emission. Their dual fluorescent character allows to track non-broken and broken bonds in dissolved and bulk polymers by fluorescence spectroscopy and microscopy. Importantly, we develop an approach to determine the absolute number and relative fraction of intact and cleaved bonds with high local resolution. We anticipate that our mechanofluorophores in combination with our quantification methodology will allow to quantitatively describe fracture processes in materials ranging from soft hydrogels to high-performance polymers.

| S-EPMC8252433 | biostudies-literature

The proton donor for O-O bond scission by cytochrome c oxidase.

Project description:Cytochrome c oxidase is the main catalyst of oxygen consumption in mitochondria and many aerobic bacteria. The key step in oxygen reduction is scission of the O-O bond and formation of an intermediate P(R) of the binuclear active site composed of heme a(3) and Cu(B). The donor of the proton required for this reaction has been suggested to be a unique tyrosine residue (Tyr-280) covalently cross-linked to one of the histidine ligands of Cu(B). To test this idea we used the Glu-278-Gln mutant enzyme from Paracoccus denitrificans, in which the reaction with oxygen stops at the P(R) intermediate. Three different time-resolved techniques were used. Optical spectroscopy showed fast (approximately 60 micros) appearance of the P(R) species along with full oxidation of heme a, and FTIR spectroscopy revealed a band at 1,308 cm(-1), which is characteristic for the deprotonated form of the cross-linked Tyr-280. The development of electric potential during formation of the P(R) species suggests transfer of a proton over a distance of approximately 4 A perpendicular to the membrane plane, which is close to the distance between the oxygen atom of the hydroxyl group of Tyr-280 and the bound oxygen. These results strongly support the hypothesis that the cross-linked tyrosine is the proton donor for O-O bond cleavage by cytochrome c oxidase and strengthens the view that this tyrosine also provides the fourth electron in O(2) reduction in conditions where heme a is oxidized.

| S-EPMC2504829 | biostudies-literature

Light in a Heartbeat: Bond Scission by a Single Photon above 800 nm.

Project description:Photocages enable scientists to take full control over the activity of molecules using light as a biocompatible stimulus. Their emerging applications in photoactivated therapies call for efficient uncaging in the near-infrared (NIR) window, which represents a fundamental challenge. Here, we report synthetically accessible cyanine photocages that liberate alcohol, phenol, amine, and thiol payloads upon irradiation with NIR light up to 820 nm in aqueous media. The photocages display a unique chameleon-like behavior and operate via two distinct uncaging mechanisms: photooxidation and heterolytic bond cleavage. The latter process constitutes the first example of a direct bond scission by a single photon ever observed in cyanine dyes or at wavelengths exceeding 800 nm. Modulation of the beating rates of human cardiomyocytes that we achieved by light-actuated release of adrenergic agonist etilefrine at submicromolar concentrations and low NIR light doses (∼12 J cm-2) highlights the potential of these photocages in biology and medicine.

| S-EPMC10979397 | biostudies-literature

Catalytic insertion of aldehydes into dihalonitroacetophenones via sequential bond scission-aldol reaction-acyl transfer.

Project description:A catalytic process that provides dihalogenated nitro alcohols in up to 99% yield and with 100% atom economy is described. In situ cleavage of dihalonitroacetophenones affords nitronates that undergo Lewis acid catalyzed addition to aldehydes. Final benzoylation renders the sequence irreversible and regenerates the bond scission and acyl transfer agent.

| S-EPMC4760845 | biostudies-literature

Studies on the chemistry and reactivity of alpha-substituted ketones in isonitrile-based multicomponent reactions.

Project description:Using the Passerini and Ugi reactions as representative tests, the utility of several alpha-substituted ketones R-CO-CH(2)-X (X = sulfonyloxy, acyloxy, azido, halo, hydroxy, and sulfonyl) in isonitrile-based multicomponent reactions was explored. In a relative rate study (R = PhCH(2)CH(2)), each of the alpha-substituted ketones underwent Passerini condensation more rapidly than the parent ketone. Short, highly convergent routes to oxazoline, beta-lactam, di-O-acylglyceramides, and other molecular frameworks were developed.

| S-EPMC2736322 | biostudies-literature

Novel isonitrile hydratase involved in isonitrile metabolism.

Project description:We previously discovered N-substituted formamide deformylase (NfdA) in Arthrobacter pascens F164, which degrades N-substituted formamide (Fukatsu, H., Hashimoto, Y., Goda, M., Higashibata, H., and Kobayashi, M. (2004) Proc. Natl. Acad. Sci. U.S.A. 101, 13726-13731). In this study, we found an enzyme involved in the first step of isonitrile metabolism, isonitrile hydratase, that hydrates isonitrile to the corresponding N-substituted formamide. First, we investigated the optimum culture conditions for the production of isonitrile hydratase. The highest enzyme activity was obtained when A. pascens F164 was cultured in a nutrient medium containing N-benzylformamide. This Arthrobacter isonitrile hydratase was purified, characterized, and compared with Pseudomonas putida N19-2 isonitrile hydratase (InhA), which is the sole one reported at present. Arthrobacter isonitrile hydratase was found to have a molecular mass of about 530 kDa and to consist of 12 identical subunits. The apparent K(m) value for cyclohexyl isocyanide was 0.95 ± 0.05 mm. A. pascens F164 grew and exhibited the isonitrile hydratase and N-substituted formamide deformylase activities when cultured in a medium containing an isonitrile as the sole carbon and nitrogen sources. However, both enzyme activities were not observed on culture in a medium containing glycerol and (NH(4))(2)SO(4) as the sole carbon and nitrogen sources, respectively. These findings suggested that the Arthrobacter enzyme is an inducible enzyme, possibly involved in assimilation and/or detoxification of isonitrile. Moreover, gene cloning of the Arthrobacter enzyme revealed no sequence similarity between this enzyme and InhA. Comparison of their properties and features demonstrated that the two enzymes are biochemically, immunologically, and structurally different from each other. Thus, we discovered a new isonitrile hydratase named InhB.

| S-EPMC2966095 | biostudies-literature

Formation of Monofluorinated Radical Cofactor in Galactose Oxidase through Copper-Mediated C-F Bond Scission.

Project description:Galactose oxidase (GAO) contains a Cu(II)-ligand radical cofactor. The cofactor, which is autocatalytically generated through the oxidation of the copper, consists of a cysteine-tyrosine radical (Cys-Tyr•) as a copper ligand. The formation of the cross-linked thioether bond is accompanied by a C-H bond scission on Tyr272 with few details known thus far. Here, we report the genetic incorporation of 3,5-dichlorotyrosine (Cl2-Tyr) and 3,5-difluorotyrosine (F2-Tyr) to replace Tyr272 in the GAOV previously optimized for expression through directed evolution. The proteins with an unnatural tyrosine residue are catalytically competent. We determined the high-resolution crystal structures of the GAOV, Cl2-Tyr272, and F2-Tyr272 incorporated variants at 1.48, 1.23, and 1.80 Å resolution, respectively. The structural data showed only one halogen remained in the cofactor, indicating that an oxidative carbon-chlorine/fluorine bond scission has occurred during the autocatalytic process of cofactor biogenesis. Using hydroxyurea as a radical scavenger, the spin-coupled hidden Cu(II) was observed by EPR spectroscopy. Thus, the structurally defined catalytic center with genetic unnatural tyrosine substitution is in the radical containing form as in the wild-type, i.e., Cu(II)-(Cl-Tyr•-Cys) or Cu(II)-(F-Tyr•-Cys). These findings illustrate a previously unobserved C-F/C-Cl bond cleavage in biology mediated by a mononuclear copper center.

| S-EPMC7737484 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data