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During normal cooking of meat, a class of mutagenic/carcinogenic compounds called heterocyclic amines is formed. Heterocyclic amines are rapidly absorbed and metabolised in the human body, and for estimation of the intake of heterocyclic amines, it is useful to determinate their levels in the urine. Blue Chitin columns were used for the extraction and purification of heterocyclic amines from urine samples spiked with 14 different heterocyclic amines. The samples were analysed using LC-MS. The results show that Blue Chitin columns provide a straightforward and rapid means of extracting heterocyclic amines from urine samples, and that Blue Chitin column are also useful in the purification of urinary metabolites. 相似文献
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(N‐heterocyclic carbene)PdCl(N‐heterocyclic carboxylate) complexes: Synthesis and catalytic activities towards arylation of benzoxazoles with aryl halides 下载免费PDF全文
Jin Yang 《应用有机金属化学》2018,32(7)
A series of N‐heterocyclic carboxylate‐stabilized N‐heterocyclic carbene palladium complexes have been synthesized and fully characterized. The solid‐state structures indicate that each of the palladium centers is coordinated by an N‐heterocyclic carbene, a chloride and a bidentate N,O‐donor N‐heterocyclic carboxylate ligand. The catalytic performance of the complexes was screened and the results revealed that the complexes exhibit moderate to high catalytic activities for the direct C─H bond arylation of benzoxazoles with aryl bromides. 相似文献
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Phenacyl bromides are used as a building blocks in synthetic organic chemistry, which serves as a key model for the development of various biologically important heterocyclic compounds and other industrially important scaffolds. This review covers recent synthetic advances in the preparation of heterocyclic compounds utilizing various phenacyl bromides. A wide range of five- and six-membered heterocyclic compounds as well as fused heterocyclic compounds were synthesized efficiently from the phenacyl bromide precursors through one-pot multicomponent reactions. 相似文献
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Salim Saranya Sankaran Radhika Cheriya Mukkolakkal Afsina Abdulla Gopinathan Anilkumar 《Journal of heterocyclic chemistry》2021,58(8):1570-1580
The synthesis of heterocyclic compounds has been a hot topic for several decades. Synthetic organic chemists are always in search of new methodologies which are greener for the synthesis of heterocyclic compounds. The ultrasound-assisted reactions have contributed much to this field. This review focuses on the impact of sonochemistry in the synthesis of heterocyclic compounds and covers the literature from 2009 to 2020. 相似文献
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Sergey P. Ivonin Andrew A. Tolmachev Alexandra A. Chaikovskaya Tamara N. Kudraya Andrew A. Anischenko Eduard B. Rusanov Alexander N. Chernega Alexandr M. Pinchuk 《Heteroatom Chemistry》2001,12(7):658-664
The reaction of phosphorus tribromide with phenylhydrazones of heterocyclic aldehydes leads to formation of a new phosphorus‐containing heterocyclic system—heterocondensed 1,2,3‐diazaphosphorines. Properties of the phosphorus‐containing heterocyclic compounds that have been synthesized are described. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:658–664, 2001 相似文献
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Reaction of lithium dimethyl copper with several heterocyclic ketones results in a 1,4-addition and introduction of a methyl group on the heterocyclic ring. In some cases, addition to the carbonyl also occurs. 相似文献
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A series of potent heterocyclic amines that are mutagenic and carcinogenic have been discovered that are formed in some heated foods, most notably, meats derived from muscle. Determining the heterocyclic amine content in foods and food products is required for toxicological research, industry quality control, and possibly in the future, regulatory control. The contents of food needs to be determined using reliable analytical techniques. Since heterocyclic amines are present in foods at ng/g levels, a variety of liquid-liquid or solid-phase purification techniques are required, followed by gas or high-performance liquid chromatography. Peak detection has been successful using UV, fluorescence, and mass spectrometric detection, and biological activity using the Ames/Salmonella test. The low levels present require that chromatographic efficiency, and both detector sensitivity and selectivity be optimized. The cartridge solid-phase extraction and high-performance liquid chromatography method have been used to measure the known food-derived heterocyclic amines for several types of food, and to the authors knowledge, this is the only method undergoing intralaboratory comparison and validation. Our analysis of the literature shows that chromatographic analysis of the heterocyclic amines by high-performance liquid chromatography or gas chromatography (with derivatization) is satisfactory for heterocyclic amine analysis in foods although the methods are just now being optimized for routine use. The biggest improvements in speed and accuracy will probably come from improved extraction methods as analysis of complex food samples for heterocyclic amines will always be a challenge. 相似文献
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[reaction: see text] The solid-phase assembly of heterocyclic amino acids enabled the total synthesis of numerous diastereoisomers of tenuecyclamides A-D, establishing or correcting the stereochemistry of each natural product. This strategy provides a very efficient route to synthesize thiazole- and oxazole-containing macrolactams from heterocyclic amino acids that are readily prepared from Fmoc-alpha-amino acids. This methodology appears to be broadly applicable to the synthesis of natural product libraries incorporating unnatural heterocyclic amino acid residues for the purpose of drug discovery. 相似文献
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Tsuchimoto T Hatanaka K Shirakawa E Kawakami Y 《Chemical communications (Cambridge, England)》2003,(19):2454-2455
Indium triflate was found to be a prominent catalyst for addition of heterocyclic arenes to alkynes to afford 2:1 adducts, where two heterocyclic arenes regioselectively attacked the same carbon atom of alkynes. 相似文献
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Jan Becher 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):289-309
Abstract Many heterocyclic o-chloroaldehydes are easy to prepare, for example via the Vilsmeier chloroformylation reaction. Due to the electron withdrawing effect of the formyl group, the halogen atom is normally a nucleofuge. This can be used to prepare a range of o-substituted heterocyclic aldehydes showing interesting rearrangement reactions. Such types of compounds are also useful as starting materials for the preparation of annelated heterocyclic systems. We have demonstrated that heterocyclic mercapto groups can be protected as t-butylthioethers. Furthermore, we have found that thiolation of heterocyclic systems containing reactive halogen substituents can conveniently be carried out via the easily prepared t-butylsulfides. This method has been used in the preparation of a number of N2S2-ligands. The resulting transition metal N2S2-complexes have been used in the study of model systems for one of the active sites in cytochrome c oxidase. The method also gives access to polymeric heterocyclic multisulfur transition metal complexes with high electrical conductivity. 相似文献
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An efficient route to a 5,6-dihydropyrano[3,4-b]pyridin-8-one core in two steps from enaminolactones
Cheikh Sall Sandrine Paquelet Jean Michel Chezal Yves Blache 《Tetrahedron letters》2008,49(8):1301-1304
A convenient two step conversion of heterocyclic enaminolactones to heterocyclic fused 2-pyran-1-ones is reported. The use of this method can be applied to a wide variety of aromatic and heteroaromatic amines to give potentially biologically active compounds in good yields. 相似文献
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A series of new heterocyclic β-ketosulfides was prepared by the reaction of the corresponding heterocyclic thiols with α-bromoacetophenone and its derivatives. Oxidation of the products using m-CPBA gave the corresponding heterocyclic β-ketosulfones, which, on treatment with Selectfluor™ under anhydrous condition underwent electrophilic fluorination resulting in new heterocycles with difluoromethylene moiety adjacent to the sulfur atom and the carbonyl group. Base-induced cleavage of the five types of the resulting products, with different heterocyclic moieties as model compounds, afforded the difluoromethyl sulfones attached to the corresponding heterocycles. They can be considered as interesting fluorinated building blocks for further elaborations. 相似文献
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The modern state of the chemistry of heterocyclic cation radicals is examined, Methods for the preparation (generation) of these particles, as well as their stabilities and the factors that determine them, are described, The mechanisms of the reactions of heterocyclic cation radicals with nucleophiles and specific examples of such reactions are discussed. Special attention is directed to the role of cation radicals as intermediate particles in dehydrogenation, nitration, and radical substitution reactions and in processes involving the cleavage of C-C bonds and dehydrodimerization in the heterocyclic series. The cation radicals of some natural heterocyclic compounds and their possible role in the functioning of biochemical systems are also examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1011–1029, August, 1980 相似文献
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Vuyolwethu Khwaza Sithenkosi Mlala Opeoluwa O. Oyedeji Blessing A. Aderibigbe 《Molecules (Basel, Switzerland)》2021,26(9)
Pentacyclic triterpenoids are well-known phytochemicals with various biological activities commonly found in plants as secondary metabolites. The wide range of biological activities exhibited by triterpenoids has made them the most valuable sources of pharmacological agents. A number of novel triterpenoid derivatives with many skeletal modifications have been developed. The most important modifications are the formation of analogues or derivatives with nitrogen-containing heterocyclic scaffolds. The derivatives with nitrogen-containing heterocyclic compounds are among the most promising candidate for the development of novel therapeutic drugs. About 75% of FDA-approved drugs are nitrogen-containing heterocyclic moieties. The unique properties of heterocyclic compounds have encouraged many researchers to develop new triterpenoid analogous with pharmacological activities. In this review, we discuss recent advances of nitrogen-containing heterocyclic triterpenoids as potential therapeutic agents. This comprehensive review will assist medicinal chemists to understand new strategies that can result in the development of compounds with potential therapeutic efficacy. 相似文献
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The reaction of heteroaroyl‐substituted heterocyclic ketene aminals with 2,3,4,6‐tetra‐O‐acetyl‐β‐D ‐glucopyranosyl azide was investigated and a series of potential bioactive compounds, 1‐glucopyranosyl‐4‐heterocyclic‐5‐heteroaryl‐1,2,3‐triazoles, were obtained in good yields. Both the reaction rate and the yield were strongly affected by the heteroaryl and heterocyclic groups. In order to improve their water solubility, the deprotection of 1‐glucopyranosyl‐4‐heterocyclic‐5‐heteroaryl‐1,2,3‐triazole was carried out. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:242–247, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10023 相似文献
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Cycloaddition of N-aryl-C-ethoxycarbonylnitrilimines and diarylnitrilimines on 1,5-benzodiazepinones was achieved in a one-pot procedure, to give a variety of compounds possessing an additional heterocyclic ring fused to the heterocyclic nucleus. This reaction was revealed to be completely peri and regioselective. The structures were elucidated by spectral methods and X-ray crystallographic analysis. 相似文献