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Molecules (Basel, Switzerland) Jul 2019The intramolecular C-H insertions of carbenes derived from 2-diazo-2-sulfamoylacetamides were studied. 2-Diazo-2-sulfamoylacetamides were first prepared from...
The intramolecular C-H insertions of carbenes derived from 2-diazo-2-sulfamoylacetamides were studied. 2-Diazo-2-sulfamoylacetamides were first prepared from chloroacetyl chloride and secondary amines through acylation followed by sequential treatments with sodium sulfite, phosphorus oxychloride, secondary amines, and 4-nitrobenzenesulfonyl azide. The results indicate that: (1) 2-diazo--dimethyl-2-(-diphenylsulfamoyl)acetamide can take the formal aromatic 1,5-C-H insertion in its -phenylsulfonamide moiety to afford the corresponding 1,3-dihydrobenzo[]isothiazole-3-carboxamide 2,2-dioxide derivative; (2) no aliphatic C-H insertions occur for 2-diazo-2-(-dialkylsulfamoyl)acetamides; and (3) for 2-diazo--phenyl-2-(-phenylsulfamoyl)acetamides, the formal aromatic 1,5-C-H insertion in the -phenylacetamide moiety is favorable to afford the corresponding 3-sulfamoylindolin-2-one derivatives as sole or major products. The intramolecular competitive aromatic 1,5-C-H insertion reactions of 2-diazo-2-sulfamoylacetamides with aryl groups on both amide and sulfonamide groups reveal that the -aryl substituents on acetamide are more active than those on sulfonamide. The chemoselectivity is controlled by electronic effect of the aryl group.
Topics: Acetamides; Carbon; Catalysis; Diazonium Compounds; Hydrogen; Methane; Sulfonamides
PubMed: 31330952
DOI: 10.3390/molecules24142628 -
Bioconjugate Chemistry Mar 2020N-Diazirines represent an attractive class of imaging tags for hyperpolarized magnetic resonance imaging (HP-MRI), offering desirable biocompatibility, ease of...
N-Diazirines represent an attractive class of imaging tags for hyperpolarized magnetic resonance imaging (HP-MRI), offering desirable biocompatibility, ease of incorporation into a variety of molecules, and ability to deliver long-lasting polarization. We have recently established hyperpolarization of N-diazirines in organic solvents using SABRE-Shield Enables Alignment Transfer to Heteronuclei (SABRE-SHEATH). Yet, the current challenge of SABRE-SHEATH in water, specifically poor polarization efficiency, presents a barrier in examining the practical use of N-diazirines for HP-MRI. Herein, we show that efficient polarization of diverse N-diazirine-labeled molecules in water can be readily achieved by dissolution dynamic nuclear polarization (d-DNP), a hyperpolarization technique used in clinical practice. Hyperpolarization by d-DNP also demonstrates greater enhancement for long-lasting N signals, in comparison with SABRE-SHEATH. Various biologically important molecules are studied in this work, including amino acid, sugar, and drug compounds, demonstrating the great potential of N-diazirines as molecular tags in broad biomedical and clinical applications.
Topics: Diazomethane; Magnetic Resonance Imaging; Nitrogen Isotopes
PubMed: 32023034
DOI: 10.1021/acs.bioconjchem.0c00028 -
Proceedings of the National Academy of... Jun 2020Modern organic reaction discovery and development relies on the rapid assessment of large arrays of hypothesis-driven experiments. The time-intensive nature of reaction...
Modern organic reaction discovery and development relies on the rapid assessment of large arrays of hypothesis-driven experiments. The time-intensive nature of reaction analysis presents the greatest practical barrier for the execution of this iterative process that underpins the development of new bioactive agents. Toward addressing this critical bottleneck, we report herein a high-throughput analysis (HTA) method of reaction mixtures by photocapture on a 384-spot diazirine-terminated self-assembled monolayer, and self-assembled monolayers for matrix-assisted laser desorption/ionization mass spectrometry (SAMDI-MS) analysis. This analytical platform has been applied to the identification of a single-electron-promoted reductive coupling of acyl azolium species.
Topics: Benzimidazoles; Diazomethane; High-Throughput Screening Assays; Oxidation-Reduction; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Ultraviolet Rays
PubMed: 32482866
DOI: 10.1073/pnas.2003347117 -
ACS Chemical Neuroscience Jan 2021The mechanisms of general anesthetics have been debated in the literature for many years and continue to be of great interest. As anesthetic molecules are notoriously...
The mechanisms of general anesthetics have been debated in the literature for many years and continue to be of great interest. As anesthetic molecules are notoriously difficult to study due to their low binding affinities and multitude of binding partners, it is advantageous to have additional tools to study these interactions. Fropofol is a hydroxyl to fluorine-substituted propofol analogue that is able to antagonize the actions of propofol. Understanding fropofol's ability to antagonize propofol would facilitate further characterization of the binding interactions of propofol that may contribute to its anesthetic actions. However, the study of fropofol's molecular interactions has many of the same difficulties as its parent compound. Here, we present the synthesis and characterization of -azi-fropofol (AziF) as a suitable photoaffinity label (PAL) of fropofol that can be used to covalently label proteins of interest to characterize fropofol's binding interactions and their contribution to general anesthetic antagonism.
Topics: Anesthetics, General; Diazomethane; Propofol
PubMed: 33355437
DOI: 10.1021/acschemneuro.0c00667 -
ChemMedChem Oct 2022Identifying the protein targets of drugs is an important but tedious process. Existing proteomic approaches enable unbiased target identification but lack the throughput...
Identifying the protein targets of drugs is an important but tedious process. Existing proteomic approaches enable unbiased target identification but lack the throughput needed to screen larger compound libraries. Here, we present a compound interaction screen on a photoactivatable cellulose membrane (CISCM) that enables target identification of several drugs in parallel. To this end, we use diazirine-based undirected photoaffinity labeling (PAL) to immobilize compounds on cellulose membranes. Functionalized membranes are then incubated with protein extract and specific targets are identified via quantitative affinity purification and mass spectrometry. CISCM reliably identifies known targets of natural products in less than three hours of analysis time per compound. In summary, we show that combining undirected photoimmobilization of compounds on cellulose with quantitative interaction proteomics provides an efficient means to identify the targets of natural products.
Topics: Biological Products; Cellulose; Diazomethane; Mass Spectrometry; Proteins; Proteomics
PubMed: 35867055
DOI: 10.1002/cmdc.202200346 -
Philosophical Transactions of the Royal... Feb 2023Non-ribosomal peptide synthetases (NRPSs) biosynthesize many pharmaceuticals and virulence factors. The biosynthesis of these natural peptide products from biosynthetic...
Non-ribosomal peptide synthetases (NRPSs) biosynthesize many pharmaceuticals and virulence factors. The biosynthesis of these natural peptide products from biosynthetic gene clusters depends on complex regulations in bacteria. However, our current knowledge of NRPSs is based on enzymological studies using full NRPS systems and/or a single NRPS domain in heterologous hosts. Chemical and/or biochemical strategies to capture the endogenous activities of NRPSs facilitate studies on NRPS cell biology in bacterial cells. Here, we describe a chemical scaffold for the rapid and selective photoaffinity labelling of NRPSs in purified systems, crude biological samples and living bacterial cells. We synthesized photoaffinity labelling probes coupled with 5'--(phenylalanyl)sulfamoyladenosine with clickable alkyl diazirine or trifluoromethyl phenyl diazirine. We found that a trifluoromethyl phenyl diazirine-based probe cross-linked the Phe-activating domain of a GrsA-NRPS with high selectivity and sensitivity at shorter ultraviolet (UV) irradiation times (less than 5 min) relative to a prototypical benzophenone-based probe. Our results demonstrated that this quick labelling protocol can prevent damage to proteins and cells caused by long UV irradiation times, providing a mild photoaffinity labelling method for biological samples. This article is part of the theme issue 'Reactivity and mechanism in chemical and synthetic biology'.
Topics: Diazomethane; Bacteria; Peptide Synthases; Multigene Family
PubMed: 36633280
DOI: 10.1098/rstb.2022.0026 -
Chembiochem : a European Journal of... Jan 2020Ultraviolent crosslinking is a key experimental step in the numerous protocols that have been developed for capturing and dissecting RNA-protein interactions in living...
Ultraviolent crosslinking is a key experimental step in the numerous protocols that have been developed for capturing and dissecting RNA-protein interactions in living cells. UV crosslinking covalently stalls dynamic interactions between RNAs and the directly contacting RNA-binding proteins and enables stringent denaturing downstream purification conditions needed for the enrichment and biochemical analysis of RNA-protein complexes. Despite its popularity, conventional 254 nm UV crosslinking possesses a set of intrinsic drawbacks, with the low photochemical efficiency being the central caveat. Here we show that genetically encoded photoreactive unnatural amino acids bearing a dialkyl diazirine photoreactive group can address this problem. Using the human iron regulatory protein 1 (IRP1) as a model RNA-binding protein, we show that the photoreactive amino acids can be introduced into the protein without diminishing its RNA-binding properties. A sevenfold increase in the crosslinking efficiency compared to conventional 254 nm UV crosslinking was achieved using the diazirine-based unnatural amino acid DiAzKs. This finding opens an avenue for new applications of the unnatural amino acids in studying RNA-protein interactions.
Topics: Cross-Linking Reagents; Diazomethane; Humans; Molecular Structure; RNA; RNA-Binding Proteins; Ultraviolet Rays
PubMed: 31658407
DOI: 10.1002/cbic.201900559 -
ACS Chemical Biology Aug 2021Aliphatic diazirine analogues of cholesterol have been used previously to elaborate the cholesterol proteome and identify cholesterol binding sites on proteins....
Aliphatic diazirine analogues of cholesterol have been used previously to elaborate the cholesterol proteome and identify cholesterol binding sites on proteins. Cholesterol analogues containing the trifluoromethylphenyl diazirine (TPD) group have not been reported. Both classes of diazirines have been prepared for neurosteroid photolabeling studies and their combined use provided information that was not obtainable with either diazirine class alone. Hence, we prepared cholesterol TPD analogues and used them along with previously reported aliphatic diazirine analogues as photoaffinity labeling reagents to obtain additional information on the cholesterol binding sites of the pentameric ligand-gated ion channel (GLIC). We first validated the TPD analogues as cholesterol substitutes and compared their actions with those of previously reported aliphatic diazirines in cell culture assays. All the probes bound to the same cholesterol binding site on GLIC but with differences in photolabeling efficiencies and residues identified. Photolabeling of mammalian (HEK) cell membranes demonstrated differences in the pattern of proteins labeled by the two classes of probes. Collectively, these date indicate that cholesterol photoaffinity labeling reagents containing an aliphatic diazirine or TPD group provide complementary information and will both be useful tools in future studies of cholesterol biology.
Topics: Alkynes; Binding Sites; Cholesterol; Cyanobacteria; Diazomethane; Fluorescent Dyes; Ligand-Gated Ion Channels; Molecular Docking Simulation; Molecular Dynamics Simulation; Photoaffinity Labels; Protein Binding
PubMed: 34355883
DOI: 10.1021/acschembio.1c00364 -
ACS Omega Aug 2023A series of 6-monohalo (Cl, Br, and I) β-cyclodextrin derivatives with various types of methylations were synthesized via a diazotization/nucleophilic displacement...
A series of 6-monohalo (Cl, Br, and I) β-cyclodextrin derivatives with various types of methylations were synthesized via a diazotization/nucleophilic displacement reaction from the corresponding methylated cyclodextrin amines. All four starting compounds (6-amino-6-deoxy derivatives of native β-CD, per-6--methyl-, per-2,3--methyl-, and per-2,3,6--methyl-β-CD) were found to have different reactivities under the same reaction conditions. Unsubstituted and fully per-O-methylated cyclodextrin amines undergo fast transformation, giving lower yields of the monohalogenated product. The selectively methylated cyclodextrin amines react remarkably slower and provide almost complete conversion into the desired monohalogenated compound. A pure product was, in several cases, successfully isolated with simple purification techniques (extraction and precipitation), allowing large-scale preparations. This new method opens the way for preparing poorly investigated monofunctionalized selectively methylated cyclodextrins.
PubMed: 37576619
DOI: 10.1021/acsomega.3c01950 -
Mercury-Free Synthesis of Pincer [C^N^C]Au Complexes by an Oxidative Addition/CH Activation Cascade.ChemSusChem Apr 2020Starting from the commercially available dimethyl sulfide-gold(I) chloride complex (DMSAuCl) and diazonium salts in the presence of 2,6-di-tert-butyl-4-methylpyridine as...
Starting from the commercially available dimethyl sulfide-gold(I) chloride complex (DMSAuCl) and diazonium salts in the presence of 2,6-di-tert-butyl-4-methylpyridine as base, symmetric and unsymmetric [C^N^C]Au Cl complexes were synthesized in a selective, photosensitizer-free, photochemical reaction using blue LED light. This new protocol provides the first mercury-free synthesis of these types of pincer-complexes in moderate-to-excellent yields, starting from a readily available gold(I) precursor. Owing to the extraordinary properties of the target compounds, like excellent luminescence and high anticancer activities, the synthesis of such complexes is a highly active field of research, which might make its way to an industrial application. Owing to the disadvantages of the known protocols, especially the toxicity and the selectivity issues in the case of unsymmetric complexes, avoiding the use of mercury, should further accelerate this ongoing development.
PubMed: 32134179
DOI: 10.1002/cssc.202000310