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Nature Communications Nov 2019Coupling reactions of amines and alcohols are of central importance for applications in chemistry and biology. These transformations typically involve the use of a...
Coupling reactions of amines and alcohols are of central importance for applications in chemistry and biology. These transformations typically involve the use of a reagent, activated as an electrophile, onto which nucleophile coupling results in the formation of a carbon-nitrogen or a carbon-oxygen bond. Several promising reagents and procedures have been developed to achieve these bond forming processes in high yields with excellent stereocontrol, but few offer direct coupling without the intervention of a catalyst. Herein, we report the synthesis of chiral donor-acceptor azetines by highly enantioselective [3 + 1]-cycloaddition of enoldiazoacetates with aza-ylides and their selective coupling with nitrogen and oxygen nucleophiles via 3-azetidinones to form amino acid derivatives, including those of peptides and natural products. The overall process is general for a broad spectrum of nucleophiles, has a high degree of electronic and steric selectivity, and retains the enantiopurity of the original azetine.
Topics: Amino Acids; Azetidines; Azetines; Catalysis; Chemistry Techniques, Synthetic; Cycloaddition Reaction; Diazonium Compounds; Indicators and Reagents; Stereoisomerism
PubMed: 31757976
DOI: 10.1038/s41467-019-13326-8 -
International Journal of Toxicology 2024-Diazirine reagents are increasingly being used as polymer crosslinkers, adhesives, and photopatterning agents in the materials sciences literature, but little effort...
-Diazirine reagents are increasingly being used as polymer crosslinkers, adhesives, and photopatterning agents in the materials sciences literature, but little effort has been made thus far to document their chemical safety profile. Here, we describe the results of a detailed toxicity assessment of a representative -diazirine. Safety was evaluated by a series of in vitro assays, which found the product to be non-mutagenic in bacterial tester strains TA98 and TA100, non-corrosive and non-irritating to skin, and requiring no classification for eye irritation or serious damage. While in vitro tests do not capture the integrated whole animal system, and thus cannot completely rule out the possibility of adverse responses, the results of this study suggest a desirable safety profile for -diazirine reagents and provide a solid foundation upon which to add in vivo assessment of safety risk and dose-response studies.
Topics: Animals; Diazomethane; Skin
PubMed: 37987615
DOI: 10.1177/10915818231215692 -
Molecules (Basel, Switzerland) Aug 2020We report a comparison of sensors' performance of different hybrid nanomaterial architectures modifying an indium tin oxide (ITO) electrode surface. Diazonium salts and...
We report a comparison of sensors' performance of different hybrid nanomaterial architectures modifying an indium tin oxide (ITO) electrode surface. Diazonium salts and gold nanoparticles (AuNPs) were used as building units to design hybrid thin films of successive layers on the ITO electrode surface. Different architectures of hybrid thin films were prepared and characterized with different techniques, such as TEM, FEG-SEM, XPS, and EIS. The prepared electrodes were used to fabricate sensors for heavy metal detection and their performances were investigated using the square wave voltammetry (SWV) method. The comparison of the obtained results shows that the deposition of AuNPs on the ITO surface, and their subsequent functionalization by diazonium salt, is the best performing architecture achieving a high sensitivity in terms of the lower detection limit of pico molar.
Topics: Biosensing Techniques; Copper; Diazonium Compounds; Electrochemical Techniques; Electrodes; Gold; Limit of Detection; Metal Nanoparticles; Tin Compounds
PubMed: 32867096
DOI: 10.3390/molecules25173903 -
Journal of the American Chemical Society Mar 2021Here we report the first example of alkyne trifunctionalization through simultaneous construction of C-C, C-O, and C-N bonds via gold catalysis. With the assistance of a...
Here we report the first example of alkyne trifunctionalization through simultaneous construction of C-C, C-O, and C-N bonds via gold catalysis. With the assistance of a γ-keto directing group, sequential gold-catalyzed alkyne hydration, vinyl-gold nucleophilic addition, and gold(III) reductive elimination were achieved in one pot. Diazonium salts were identified as both electrophiles (N source) and oxidants (C source). Vinyl-gold(III) intermediates were revealed as effective nucleophiles toward diazonium, facilitating nucleophilic addition and reductive elimination with high efficiency. The rather comprehensive reaction sequence was achieved with excellent yields (up to 95%) and broad scope (>50 examples) under mild conditions (room temperature or 40 °C).
Topics: Alkynes; Catalysis; Diazonium Compounds; Gold; Oxidation-Reduction; Quantum Theory; Temperature; Vinyl Compounds
PubMed: 33661619
DOI: 10.1021/jacs.1c01811 -
The Biochemical Journal Jun 1973Dimethoxybilirubin dimethyl ester and monomethoxybilirubin dimethyl ester were prepared by treating bilirubin with diazomethane, and the correctness of the assigned...
Dimethoxybilirubin dimethyl ester and monomethoxybilirubin dimethyl ester were prepared by treating bilirubin with diazomethane, and the correctness of the assigned structures was proved by elemental analysis as well as by i.r. and n.m.r. spectroscopy. The phenylazo compounds derived from monomethoxybilirubin dimethyl ester were also prepared and characterized spectroscopically. Dimethoxybilirubin dimethyl ester occurs in solution as a single molecular species, unlike bilirubin dimethyl ester, which in non-polar solvents exists as an equilibrium mixture of conformational isomers. This difference in the behaviour of the two compounds is explained by the absence of intramolecular hydrogen bonds in dimethoxybilirubin dimethyl ester, a situation that allows free rotation about the central methylene bridge, whereas in bilirubin dimethyl ester an internally hydrogen-bonded conformation can be distinguished by n.m.r. spectroscopy from a non-bonded family of rotamers. This finding is regarded as additional evidence for a newly conceived conformational structure of bilirubin and bilirubin dimethyl ester that is maximally stabilized by intramolecular hydrogen bonds. This is discussed in detail in the Appendix (Kuenzle et al., 1973), which also includes a description of the molecular mechanism pertaining to the reaction of bilirubin with diazomethane.
Topics: Aluminum; Bilirubin; Binding Sites; Chromatography; Chromatography, Thin Layer; Diazomethane; Magnetic Resonance Spectroscopy; Methyl Ethers; Molecular Conformation; Protein Binding; Spectrophotometry; Spectrophotometry, Infrared
PubMed: 4723780
DOI: 10.1042/bj1330357 -
Biosensors Mar 2016Nanostring resonator and fiber-optics-based biosensors are of interest as they offer high sensitivity, real-time measurements and the ability to integrate with...
Nanostring resonator and fiber-optics-based biosensors are of interest as they offer high sensitivity, real-time measurements and the ability to integrate with electronics. However, these devices are somewhat impaired by issues related to surface modification. Both nanostring resonators and photonic sensors employ glassy materials, which are incompatible with electrochemistry. A surface chemistry approach providing strong and stable adhesion to glassy surfaces is thus required. In this work, a diazonium salt induced aryl film grafting process is employed to modify a novel SiCN glassy material. Sandwich rabbit IgG binding assays are performed on the diazonium treated SiCN surfaces. Fluorescently labelled anti-rabbit IgG and anti-rabbit IgG conjugated gold nanoparticles were used as markers to demonstrate the absorption of anti-rabbit IgG and therefore verify the successful grafting of the aryl film. The results of the experiments support the effectiveness of diazonium chemistry for the surface functionalization of SiCN surfaces. This method is applicable to other types of glassy materials and potentially can be expanded to various nanomechanical and optical biosensors.
Topics: Animals; Biosensing Techniques; Diazonium Compounds; Eyeglasses; Gold; Metal Nanoparticles; Photoelectron Spectroscopy; Rabbits; Surface Properties
PubMed: 26985910
DOI: 10.3390/bios6010008 -
Accounts of Chemical Research Sep 2011DNA is not merely a combination of four genetic codes, namely A, T, C, and G. It also contains minor modifications that play crucial roles throughout biology. For...
DNA is not merely a combination of four genetic codes, namely A, T, C, and G. It also contains minor modifications that play crucial roles throughout biology. For example, the fifth DNA base, 5-methylcytosine (5-mC), which accounts for ∼1% of all the nucleotides in mammalian genomic DNA, is a vital epigenetic mark. It impacts a broad range of biological functions, from development to cancer. Recently, an oxidized form of 5-methylcytosine, 5-hydroxymethylcytosine (5-hmC), was found to constitute the sixth base in the mammalian genome; it was believed to be another crucial epigenetic mark. Unfortunately, further study of this newly discovered DNA base modification has been hampered by inadequate detection and sequencing methods, because current techniques fail to differentiate 5-hmC from 5-mC. The immediate challenge, therefore, is to develop robust methods for ascertaining the positions of 5-hmC within the mammalian genome. In this Account, we describe our development of the first bioorthogonal, selective labeling of 5-hmC to specifically address this challenge. We utilize β-glucosyltransferase (βGT) to transfer an azide-modified glucose onto 5-hmC in genomic DNA. The azide moiety enables further bioorthogonal click chemistry to install a biotin group, which allows for detection, affinity enrichment, and, most importantly, deep sequencing of the 5-hmC-containing DNA. With this highly effective and selective method, we revealed the first genome-wide distribution of 5-hmC in the mouse genome and began to shed further light on the biology of 5-hmC. The strategy lays the foundation for developing high-throughput, single-base-resolution sequencing methods for 5-hmC in mammalian genomes in the future. DNA and RNA are not static inside cells. They interact with protein and other DNA and RNA in fundamental biological processes such as replication, transcription, translation, and DNA and RNA modification and repair. The ability to investigate these interactions will also be enhanced by developing and utilizing bioorthogonal probes. We have chosen the photoreactive diazirine photophore as a bioorthogonal moiety to develop nucleic acid probes. The small size and unique photo-cross-linking activity of diazirine enabled us to develop a series of novel cross-linking probes to streamline the study of protein-nucleic acid and nucleic acid-nucleic acid interactions. In the second half of this Account, we highlight a few examples of these probes.
Topics: 5-Methylcytosine; Animals; Azides; Biotin; Cell Line; Click Chemistry; Cross-Linking Reagents; Cytosine; DNA; DNA Probes; Diazomethane; Genome; Glucosyltransferases; Humans; Mice; Streptavidin; Ultraviolet Rays
PubMed: 21539303
DOI: 10.1021/ar2000502 -
Chemistry (Weinheim An Der Bergstrasse,... Oct 2021Although incorporation of photo-activatable lipids into membranes potentially opens up novel avenues for investigating interactions with proteins, the question of...
Although incorporation of photo-activatable lipids into membranes potentially opens up novel avenues for investigating interactions with proteins, the question of whether diazirine-modified lipids are suitable for such studies, remains under debate. Focusing on the potential for studying lipid/peptide interactions by cross-linking mass spectrometry (XL-MS), we developed a diazirine-modified lipid (DiazPC), and examined its behaviour in membranes incorporating the model α-helical peptide LAVA20. We observed an unexpected backfolding of the diazirine-containing stearoyl chain of the lipid. This surprising behaviour challenges the potential application of DiazPC for future XL-MS studies of peptide and protein/lipid interactions. The observations made for DiazPC most likely represent a general phenomenon for any type of membrane lipids with a polar moiety incorporated into the alkyl chain. Our finding is therefore of importance for future protein/lipid interaction studies relying on modified lipid probes.
Topics: Cross-Linking Reagents; Diazomethane; Mass Spectrometry; Membrane Lipids; Peptides
PubMed: 34406694
DOI: 10.1002/chem.202102048 -
The Biochemical Journal Feb 1985We describe a facile and sensitive reverse-phase h.p.l.c. method for analytical separation of biliary bile pigments and direct quantification of unconjugated bilirubin...
Reverse-phase h.p.l.c. separation, quantification and preparation of bilirubin and its conjugates from native bile. Quantitative analysis of the intact tetrapyrroles based on h.p.l.c. of their ethyl anthranilate azo derivatives.
We describe a facile and sensitive reverse-phase h.p.l.c. method for analytical separation of biliary bile pigments and direct quantification of unconjugated bilirubin (UCB) and its monoglucuronide (BMG) and diglucuronide (BDG) conjugates in bile. The method can be 'scaled up' for preparative isolation of pure BDG and BMG from pigment-enriched biles. We employed an Altex ultrasphere ODS column in the preparative steps and a Waters mu-Bondapak C18 column in the separatory and analytical procedures. Bile pigments were eluted with ammonium acetate buffer, pH 4.5, and a 20 min linear gradient of 60-100% (v/v) methanol at a flow rate of 2.0 ml/min for the preparative separations and 1.0 ml/min for the analytical separations. Bile pigments were eluted in order of decreasing polarity (glucuronide greater than glucose greater than xylose conjugates greater than UCB) and were chemically identified by t.l.c. of their respective ethyl anthranilate azo derivatives. Quantification of UCB was carried out by using a standard curve relating a range of h.p.l.c. integrated peak areas to concentrations of pure crystalline UCB. A pure crystalline ethyl anthranilate azo derivative of UCB (AZO . UCB) was employed as a single h.p.l.c. reference standard for quantification of BMG and BDG. We demonstrate that: separation and quantification of biliary bile pigments are rapid (approximately 25 min); bile pigment concentrations ranging from 1-500 microM can be determined 'on line' by using 5 microliters of bile without sample pretreatment; bilirubin conjugates can be obtained preparatively in milligram quantities without degradation or contamination by other components of bile. H.p.l.c. analyses of a series of mammalian biles show that biliary UCB concentrations generally range from 1 to 17 microM. These values are considerably lower than those estimated previously by t.l.c. BMG is the predominant, if not exclusive, bilirubin conjugate in the biles of a number of rodents (guinea pig, hamster, mouse, prairie dog) that are experimental models of both pigment and cholesterol gallstone formation. Conjugated bilirubins in the biles of other animals (human, monkey, pony, cat, rat and dog) are chemically more diverse and include mono-, di- and mixed disconjugates of glucuronic acid, xylose and glucose in proportions that give distinct patterns for each species.
Topics: Animals; Bile; Bile Pigments; Bilirubin; Cats; Chromatography, High Pressure Liquid; Cricetinae; Diazonium Compounds; Dogs; Guinea Pigs; Haplorhini; Horses; Humans; Mice; Pyrroles; Rats; Sciuridae; Species Specificity; Tetrapyrroles; Time Factors
PubMed: 3919713
DOI: 10.1042/bj2250787 -
Yakugaku Zasshi : Journal of the... Nov 2008Formation of a covalent bond using photoreactive groups allows one to maintain the complex between the ligand and its binding protein even under denaturing conditions.... (Review)
Review
Formation of a covalent bond using photoreactive groups allows one to maintain the complex between the ligand and its binding protein even under denaturing conditions. Thus, the photoreactive groups functioned as the powerful hook in the fishing of specific binding proteins. This is a very useful feature for developing the efficient and sensitive methods in molecular biology. Among the photoreactive groups, carbene-generating phenyldiazirine is a first choice for the application to the methods because the use of phenyldiazirine seems to be promising for achieving efficient crosslinking. This review describes improvements of phenyldiazirine usability and an application of phenyldiazirine to displayed phage screening. We synthesized the photoreactive diazirine units for a solution to preparing photoreactive ligands. Since the photoreactive units can be easily integrated into physiological ligands such as peptides, proteins, DNAs, and sugars by chemoselective reaction, the biochemists, who are not familiar with organic synthesis, can prepare the photoaffinity ligands using their interested ligands. We applied the phenyldiazirine to screening of displayed phages, and investigated the screening efficiency. The phages displayed specific-binding protein were extremely concentrated by using photoreactive peptide bearing diazirine. High efficiency in the screening is due to carry out intensive washing which removes almost all the unspecific binding phages. Moreover, such application overcomes the unavoidable drawback of photoreactive groups, the low efficiency of crosslinking because the isolated genes can be amplified.
Topics: Diazomethane; Molecular Biology; Organic Chemistry Phenomena; Peptide Library; Photochemistry; Proteomics
PubMed: 18981697
DOI: 10.1248/yakushi.128.1615