Month: April 2022

SDS of cas: 2150-55-2. So far, in addition to halogen atoms, other non-metallic atoms can become part of the aromatic heterocycle, and the target ring system is still aromatic. Compound: 2-Amino-4,5-dihydrothiazole-4-carboxylic acid, is researched, Molecular C4H6N2O2S, CAS is 2150-55-2, about Quantification of 2-aminothiazoline-4-carboxylic acid as a reliable marker of cyanide exposure using chemical derivatization followed by liquid chromatography-tandem mass spectrometry.

In this research, we have developed a novel and simple liquid chromatog. coupled with electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) method for quantification of 2-aminothiazoline-4-carboxylic acid (ATCA), which is produced by the direct reaction of cyanide (CN) with endogenous cystine. In forensic science, detection of CN is important because CN is a poison that is often used for murder or suicide, in addition to being produced by the thermal decomposition of natural or synthetic materials. However, because CN disappears rapidly from body tissue, ATCA is thought to be a more reliable indicator of CN exposure. For the method reported herein, human blood samples (20μL) were subjected to protein precipitation followed by derivatization with 4-bromoethyl-7-methoxycoumarin. Blood spiked with ATCA at concentrations ranging from 50 to 1500 ng/mL was used to prepare a calibration curve (lower limit of quantification; 50 ng/mL, lower limit of detection; 25 ng/mL). Our method uses chem. derivatization, so unlike previously reported methods, it does not require tedious pretreatment procedures, hydrophilic interaction liquid chromatog. columns, or specialized equipment. In addition, our method allows for repeatable and accurate quantification of ATCA, with intra- and inter-assay coefficients of variation of below 5.0% and below 6.0%, resp. We used the method to analyze ATCA in postmortem human blood samples, including samples from people who had intentionally ingested CN or were fire victims. Blood ATCA concentrations were higher among people who had ingested CN or were fire victims than among people in a control group (P < 0.0001). The data reported herein demonstrate that our LC/ESI-MS/MS method can be used to detect and quantify ATCA in postmortem blood samples and that CN exposure strongly affects ATCA concentration, providing a useful tool for detection of CN poisoning. From this literature《Quantification of 2-aminothiazoline-4-carboxylic acid as a reliable marker of cyanide exposure using chemical derivatization followed by liquid chromatography-tandem mass spectrometry》,we know some information about this compound(2150-55-2)SDS of cas: 2150-55-2, but this is not all information, there are many literatures related to this compound(2150-55-2).

Reference:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Synthetic Route of C5H5FN2. The fused heterocycle is formed by combining a benzene ring with a single heterocycle, or two or more single heterocycles. Compound: 5-Amino-2-fluoropyridine, is researched, Molecular C5H5FN2, CAS is 1827-27-6, about Amide-containing α-hydroxytropolones as inhibitors of hepatitis B virus replication. Author is Li, Qilan; Lomonosova, Elena; Donlin, Maureen J.; Cao, Feng; O’Dea, Austin; Milleson, Brienna; Berkowitz, Alex J.; Baucom, John-Charles; Stasiak, John P.; Schiavone, Daniel V.; Abdelmessih, Rudolf G.; Lyubimova, Anastasiya; Fraboni, Americo J.; Bejcek, Lauren P.; Villa, Juan A.; Gallicchio, Emilio; Murelli, Ryan P.; Tavis, John E..

The Hepatitis B Virus (HBV) RNase H (RNaseH) is a promising but unexploited drug target. Here, we synthesized and analyzed a library of 57 amide-containing α-hydroxytropolones (αHTs) as potential leads for HBV drug development. Fifty percent effective concentrations ranged from 0.31 to 54μM, with selectivity indexes in cell culture of up to 80. Activity against the HBV RNaseH was confirmed in semi-quant. enzymic assays with recombinant HBV RNaseH. The compounds were overall poorly active against human RNase H1, with 50% inhibitory concentrations of 5.1 to >1,000μM. The aHTs had modest activity against growth of the fungal pathogen Cryptococcus neoformans, but had very limited activity against growth of the Gram – bacterium Escherichia coli and the Gram + bacterium Staphylococcus aureus, indicating substantial selectivity for HBV. A mol. model of the HBV RNaseH templated against the Ty3 RNaseH was generated. Docking the compounds to the RNaseH revealed the anticipated binding pose with the divalent cation coordinating motif on the compounds chelating the two Mn++ ions modeled into the active site. These studies reveal that that amide aHTs can be strong, specific HBV inhibitors that merit further assessment toward becoming anti-HBV drugs.

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Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Detoxication of cyanide by cystine》. Authors are Wood, John L.; Cooley, Shirley Lucille.The article about the compound:2-Amino-4,5-dihydrothiazole-4-carboxylic acidcas:2150-55-2,SMILESS:O=C(C1N=C(N)SC1)O).Category: pyrazines. Through the article, more information about this compound (cas:2150-55-2) is conveyed.

cf. C.A. 46, 5633a. Chem. studies on the nature of the reaction product between cystine and cyanide support formulation of the structure as 2-imino-4-thiazolidinecarboxylic acid (I). I was inert metabolically when fed to the rat or injected. I with acid yielded a small amount of thiocyanate. I was isolated from the urine of rats given NaCN subcutaneously; 80% of the cyanide was accounted for as thiocyanate. When L-cystine-S35 was administered 1st, the compounds excreted were labeled. Radioactivity measurements showed that I came from cystine, while the thiocyanate was formed from other sources of S. The reaction with cystine constitutes an independent pathway for detoxification of cyanide. The method of Schöberl and Hamm (C.A. 43, 1014f) yielded 66% I, m. 212°, [α]D29 -2.18° (c 1, water). I with Raney Ni yielded alanine. I with Ac2O in alk. aqueous solution yielded the 3-Ac compound (II), m. 179-80°, [α]D29 -1.52° (c 1, water). I (5 g.) in EtOH saturated with dry HCl and allowed to stand 24 hrs. yielded 5 g. Et ester-HCl, m. 115-16°. The Et ester of II, m. 136°.

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Reference:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Heterocyclic compounds can be divided into two categories: alicyclic heterocycles and aromatic heterocycles. Compounds whose heterocycles in the molecular skeleton cannot reflect aromaticity are called alicyclic heterocyclic compounds. Compound: 118994-89-1, is researched, Molecular C6H7NO3, about A general route to the Streptomyces-derived inthomycin family: the first synthesis of (+)-inthomycin B, the main research direction is asym synthesis inthomycin B Stille coupling palladium catalyst; Stille coupling stannyl diene oxazole vinyl iodide; Kiyooka ketene acetal amino acid derived oxazaborolidinone directed aldol.Quality Control of Ethyl oxazole-5-carboxylate.

A concise, convergent and stereocontrolled synthesis of (+)-inthomycin B (I), based on the Stille coupling of a stannyl-diene with an oxazole vinyl iodide unit, is described. The asym. center was introduced using the Kiyooka ketene acetal/amino acid-derived oxazaborolidinone procedure.

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Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Safety of Ethyl oxazole-5-carboxylate. Aromatic compounds can be divided into two categories: single heterocycles and fused heterocycles. Compound: Ethyl oxazole-5-carboxylate, is researched, Molecular C6H7NO3, CAS is 118994-89-1, about Decarboxylative C-H Cross-Coupling of Azoles. Author is Zhang, Fengzhi; Greaney, Michael F..

An intermol. decarboxylative C-H cross-coupling between oxazoles and thiazoles with the rapid synthesis of functionalized polyazoles is described. E.g., in presence of Pd(OAc)2, copper carbonate, and 1,2-bis(dicyclohexylphosphino)ethane, decarboxylative C-H cross-coupling of thiazolecarboxylic acid I and oxazole II gave 80% bis(azole) III.

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Reference:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Epoxy compounds usually have stronger nucleophilic ability, because the alkyl group on the oxygen atom makes the bond angle smaller, which makes the lone pair of electrons react more dissimilarly with the electron-deficient system. Compound: 2-Amino-4,5-dihydrothiazole-4-carboxylic acid, is researched, Molecular C4H6N2O2S, CAS is 2150-55-2, about Cloning, expression, characterization and application of atcA, atcB and atcC from Pseudomonas sp. for the production of L-cysteine.Formula: C4H6N2O2S.

An isolate of a Pseudomonas sp. uses the L-NCC (N-carbamoyl-L-cysteine) pathway to convert DL-2-amino-Δ2-thiazoline-4-carboxylic acid (DL-ATC) to L-cysteine. Genes encoding ATC racemase (AtcA), L-ATC hydrolase (AtcB) and L-NCC amidohydrolase (AtcC), involved in this pathway, were cloned from the Pseudomonas sp. and expressed in Escherichia coli BL21 via pET-28a(+). The resulting enzymes were purified, their functions identified, and their biochem. properties are described. In vitro catalysis experiments, using these enzymes, revealed that the bioconversion rate of L-cysteine from DL-ATC in the presence of AtcA was more efficient than in the absence of AtcA. This is the first report describing simultaneous cloning and expression of atcA, atcB and atcC and characterization of their enzymes for L-cysteine production from DL-ATC via the L-NCC pathway, enabling the complete L-NCC pathway to be elucidated.

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Reference:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Category: pyrazines. The protonation of heteroatoms in aromatic heterocycles can be divided into two categories: lone pairs of electrons are in the aromatic ring conjugated system; and lone pairs of electrons do not participate. Compound: 2-Amino-4,5-dihydrothiazole-4-carboxylic acid, is researched, Molecular C4H6N2O2S, CAS is 2150-55-2, about One-pot synthesis of DL-2-amino-2-thiazoline-4-carboxylic acid. Author is Xuan, Richeng; Hu, Weixiao; Yang, Zhongyu.

DL-2-Amino-2-thiazoline-4-carboxylic acid was prepared in one-pot reaction from 2,3-dichloropropionic acid. Not only the procedure was simplified, but also the yield was increased from less than 63% recorded to 93%.

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Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Quality Control of 4-Aminopyrimidine. The mechanism of aromatic electrophilic substitution of aromatic heterocycles is consistent with that of benzene. Compound: 4-Aminopyrimidine, is researched, Molecular C4H5N3, CAS is 591-54-8, about Hydrodifluoromethylation of Alkenes with Difluoroacetic Acid. Author is Meyer, Claudio F.; Hell, Sandrine M.; Misale, Antonio; Trabanco, Andres A.; Gouverneur, Veronique.

A facile method for the regioselective hydrodifluoromethylation of alkenes is reported using difluoroacetic acid and phenyliodine(III) diacetate in THF under visible-light activation. This metal-free approach stands out as it uses inexpensive reagents, does not require a photocatalyst, and displays broad functional group tolerance. The procedure is also operationally simple and scalable, and provides access in one step to high-value building blocks for application in medicinal chem.

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Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

The preparation of ester heterocycles mostly uses heteroatoms as nucleophilic sites, which are achieved by intramolecular substitution or addition reactions. Compound: 2-Amino-4,5-dihydrothiazole-4-carboxylic acid( cas:2150-55-2 ) is researched.HPLC of Formula: 2150-55-2.Baskin, Steven I.; Petrikovics, Ilona; Platoff, Gennady E.; Rockwood, Gary A.; Logue, Brian A. published the article 《Spectrophotometric analysis of the cyanide metabolite 2-aminothiazoline-4-carboxylic acid (ATCA)》 about this compound( cas:2150-55-2 ) in Toxicology Mechanisms and Methods. Keywords: cyanide metabolite aminothiazoline carboxylic acid preparation spectrophotometry. Let’s learn more about this compound (cas:2150-55-2).

Methods of directly evaluating cyanide levels are limited by the volatility of cyanide and by the difficulty of establishing steady-state cyanide levels with time. We investigated the measurement of a stable, toxic metabolite, 2-aminothiazoline-4-carboxylic acid (ATCA), in an attempt to circumvent the challenge of directly determining cyanide concentrations in aqueous media. This study was focused on the spectrophotometric ATCA determination in the presence of cyanide, thiocyanate (SCN-), cysteine, rhodanese, thiosulfate, and other sulfur donors. The method involves a thiazolidine ring opening in the presence of p-(hydroxy-mercury)-benzoate, followed by the reaction with diphenylthiocarbazone (dithizone). The product is spectrophotometrically analyzed at 625 nm in CCl4. The calibration curve was linear with a regression line of Y = 0.0022x (R2 = 0.9971). Interference of cyanide antidotes with the method was determined Cyanide, thiosulfate, butanethiosulfonate (BTS), and rhodanese did not appreciably interfere with the anal., but SCN- and cysteine significantly shifted the standard curve. This sensitive spectrophotometric method has shown promise as a substitute for the measurement of the less stable cyanide.

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Reference:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Most of the compounds have physiologically active properties, and their biological properties are often attributed to the heteroatoms contained in their molecules, and most of these heteroatoms also appear in cyclic structures. A Journal, Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov’t, Non-P.H.S., Biomarkers called Comparison of cyanide exposure markers in the biofluids of smokers and non-smokers, Author is Vinnakota, Chakravarthy V.; Peetha, Naga S.; Perrizo, Mitch G.; Ferris, David G.; Oda, Robert P.; Rockwood, Gary A.; Logue, Brian A., which mentions a compound: 2150-55-2, SMILESS is O=C(C1N=C(N)SC1)O, Molecular C4H6N2O2S, Synthetic Route of C4H6N2O2S.

Cyanide is highly toxic and is present in many foods, combustion products (e.g. cigarette smoke), industrial processes, and has been used as a terrorist weapon. In this study, cyanide and its major metabolites, thiocyanate and 2-amino-2-thiazoline-4-carboxylic acid (ATCA), were analyzed from various human biofluids of smokers (low-level chronic cyanide exposure group) and non-smokers to gain insight into the relationship of these biomarkers to cyanide exposure. The concentrations of each biomarker tested were elevated for smokers in each biofluid. Significant differences (p < 0.05) were found for thiocyanate in plasma and urine, and ATCA showed significant differences in plasma and saliva. Addnl., biomarker concentration ratios, correlations between markers of cyanide exposure, and other statistical methods were performed to better understand the relationship between cyanide and its metabolites. Of the markers studied, the results indicate plasma ATCA, in particular, showed excellent promise as a biomarker for chronic low-level cyanide exposure. From this literature《Comparison of cyanide exposure markers in the biofluids of smokers and non-smokers》,we know some information about this compound(2150-55-2)Synthetic Route of C4H6N2O2S, but this is not all information, there are many literatures related to this compound(2150-55-2).

Reference:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem