Phenacyl bromide: A versatile organic intermediate for the synthesis of heterocyclic compounds

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.     

Blue Chitin Columns for the Extraction of Heterocyclic Amines from Urine Samples

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.     

(N‐heterocyclic carbene)PdCl(N‐heterocyclic carboxylate) complexes: Synthesis and catalytic activities towards arylation of benzoxazoles with aryl halides

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.     

A New Pathway to Synthesize Cyclomercurated Ferrocenylimines Containing Heterocyclic Ring

The cyclomercurated ferrocenylimines containing heterocyclic ring were prepared by the condensation of cyclomercuration of acylferrocene with the appropriate heterocyclic amine.This procedure provides an efficient method for the synthesis of cyclomerucurated ferrocenylimines containing heterocyclic ring which are difficultly synthesized by the conventional method.The reaction mechanism is proposed.     

Heterocondensed 1,2,3‐diazaphosphorines

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     

醌式杂环化合物的设计、合成及应用性能研究进展

醌式杂环(噻吩、吡咯、呋喃等)分子具有结构刚性、最高占据分子轨道(HOMO)/最低未占据分子轨道(LUMO)能级低、能级带隙窄和摩尔消光系数高等特点.醌式分子因其结构平面性特点,分子间作用力较强,因而分子间电荷传输能力强.目前,醌式杂环分子已成为有机半导体材料领域特别是有机场效应晶体管领域的研究热点.根据醌式杂环分子的结构特点,以端基为分类依据,综述了近年来醌式杂环化合物在分子设计、合成及应用性能等方面的研究进展,并展望了醌式杂环分子的发展前景.     

Ultrasound irradiation in heterocycle synthesis: An overview

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.     

Organic electrochemistry: Anodic construction of heterocyclic structures

The construction of heterocyclic frameworks constitutes one of the most dynamic and attractive branches in organic chemistry. Electrochemistry provides a versatile and powerful approach to assemble a heterocyclic skeleton. In this review, a selection of representative examples published during 2018–2019 are presented and discussed to showcase how to make use of anodic oxidation for the constitution of heterocyclic compounds.     

Pentacyclic Triterpenoids with Nitrogen-Containing Heterocyclic Moiety,Privileged Hybrids in Anticancer Drug Discovery

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.     

AROMATIC AND HETEROCYCLIC DINITRILES AND THEIR POLYMERS. Ⅺ. STUDY ON THE POLYMERIZATION OF AROMATIC AND HETEROCYCLIC DINITRILES BY INFRARED SPECTROSCOPY*

The polymerization rates of fourteen aromatic and heterocyclic dinitriles were measured by infraredspectroscopy and compared with that of 4, 4′-biphenyldicarbonitrile. The rate is greatly enhancedwhen an electron withdrawing group is substituted at the para position of cyano group in aromaticdinitriles. The polymerization rates of heterocyclic dinitriles wer discussed in terms of π-lectrondensity of the heterocyclic rings.     

异色满酮-4及其衍生物的合成IX异香豆素并杂环化合物的合成

本文通过3, 4-二氢异苯并吡喃酮-4和其β-二酮衍生物的缩合反应, 合成出3, 4-二氢异苯并吡喃并吲哚、并喹啉、并吡唑和并嘧啶类化合物, 并进一步氧化成标题化合物。所合成的新化合物均经核磁共振光谱红外光谱及元素分析证明其分子结构。     

Synthesis of pyrylium salts and pyridines containing heterocyclic substituents

A method of synthesizing pyrylium salts with heterocyclic substituents in the ring, has been investigated. The synthesis was carried out in two stages: alkaline condensation of aromatic and heterocyclic aldehydes with methyl ketones to give 1, 5-diketones, followed by cyclization to pyrylium salts by treatment with triphenylmethyl perchlorate. Pyridines containing heterocyclic substituents were obtained by treating the pyrylium salts with ammonia.     

Synthesis of difluorinated β-ketosulfones and novel gem-difluoromethylsulfone-containing heterocycles as fluorinated building blocks

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.     

Recent Heterocyclic Compounds from (1,3‐Dioxo‐2,3‐dihydro‐1H‐inden‐2‐ylidene)propanedinitrile

This review summarizes the literatures dealing with the synthesis of some important nitrogen or nitrogen/sulfur heterocyclic, spiroheterocyclic, and fused heterocyclic compounds.     

杂环化合物氮氧化反应研究的新进展

杂环化合物的N-氧化物是一类重要的有机中间体, 也可以直接用作催化剂、炸药等. 综述了杂环化合物N-氧化反应的最新进展, 包括单氮、双氮和多氮杂环化合物的N-氧化反应, 以及在形成N→O基团的同时合成目标产物的反应, 并重点讨论了具有复杂结构的杂环化合物N-氧化反应.     

Efficient Synthesis of Five Types of Heterocyclic Compounds via Intramolecular Elimination Using Ultrasound‐Static Heating Technique

An experimental technique, ultrasound‐static heating, has been developed for the efficient synthesis of heterocyclic compounds. The technique involves ultrasonic irradiation and static heating processes. First, the ultrasonic irradiation process is performed to form an intermediate of the heterocyclic compound under mild conditions and the subsequent static heating process (heating the intermediate under solvent‐free conditions without stirring) produces the target heterocyclic compounds via intramolecular elimination.     

Chromatographic methods for the analysis of heterocyclic amine food mutagens/carcinogens.

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.     

Spectroscopic study of rigid-rod polymers. II. Protonation effect

The protonation of a heterocyclic rigid-rod polymer poly(p-phenylene benzbisthiazole) and its model compound has been studied by UV-visible and Raman spectroscopy. Because of the two nitrogens on the heterocyclic ring, spectroscopic features of unprotonated, half-protonated, and fully protonated structures have been identified. For the fully protonated molecule, there is also an increase in conjugation between the phenyl ring and the heterocyclic ring.     

过渡金属催化合成含氮杂环化合物的研究进展

含氮杂环化合物是一类非常重要的有机杂环化合物,也是有机合成化学的研究热点之一。本文首先简要介绍了含氮杂环化合物在天然产物、合成药物和功能材料中的分布及其广泛应用;然后以不同过渡金属催化剂为线索,按照时间由远至近的顺序分别概述了Pd、Ag、Fe、Ni、Zn、Cu等六类过渡金属催化剂在合成五、六元含氮杂环化合物方面的研究进展,对反应条件、反应特征进行了概括;最后对含氮杂环化合物合成领域的过渡金属催化剂的整体发展趋势进行了归纳总结。