2-氯-4-硝基吡啶的合成

２－氯－４－硝基吡啶是吡啶基苯脲类植物生长调节剂、除草剂和吡啶基医药产品的重要中间合成体。以自制的２－氯吡啶为起始原料,经过氧化、硝化和还原三步反应对其进行了实验室的合成研究,拟在为今后的工业化生产提供强有力的实验依据。     

4—氨基—2—氯吡啶的合成研究

在对４－氨基－２－氯吡啶合成路线进行分析评价的基础上，以２－氯吡啶－Ｎ－氧化物为起始原料，经过硝化和还原两步反应，者了以工业化为目的的合成研究，产品总收率达到５６％。     

2-巯基吡啶-1-氧化物制备的改进

２－巯基吡啶－１－氧化物（１）是广谱的抗菌剂,对革兰氏阳性菌、革兰氏阴性菌及真菌都有效。它可通过皮肤吸收,控制皮脂溢出性皮炎和头皮屑。文献报道,（１）的合成是以２－氯吡啶－１－氧化物为原料,经硫脲或硫化钠或硫氢化钠巯基化而制得。ＮＯ↓ＣｌＣＮＨ２ＳＨ...     

2-氯吡啶的合成与应用

介绍了２－氯吡啶的物理性质,合成方法及主要应用。     

2-（3-氯吡啶-2-基）-5-羟基吡唑-3-甲酸乙酯的合成

2-(3-氯吡啶-2-基)-5-羟基吡唑-3-甲酸乙酯是合成氯虫酰胺杀虫剂的一种重要中间体。以2,3-二氯吡啶为原料经肼解、环合两步反应合成2-(3-氯吡啶-2-基)-5-羟基吡唑-3-甲酸乙酯,并对其工艺做了改进和优化,总收率43.1%。其中,3-氯-2-肼基吡啶采用无溶剂法合成,工艺过程简单。     

2-氯-5-氯甲基吡啶的合成工艺路线述评

2-氯-5-氯甲基吡啶是合成吡虫啉、烯啶虫胺等多种农药及医药的关键中间体.对国内外报道的关于2-氯-5-氯甲基吡啶的合成工艺路线进行了系统的总结,并对目前开发比较成熟的工艺路线进行了综合评述,对今后合成2-氯-5-氯甲基吡啶工艺的发展方向给予客观、科学的预测.     

2-氯-3-碘吡啶的合成研究

2-氯-3-碘吡啶是合成磺酰脲类除草剂啶嘧黄隆中间体2-氯-3-三氟甲基吡啶的重要原料。本文以2-氯-3-氨基吡啶为原料,经过重氮化,碘化反应合成2-氯-3-碘吡啶,样品经提纯后收率在80%左右,产物结构经1HNMK、IK鉴定。     

2－氯－4－氨基吡啶的合成

以２－氨基吡啶为原料，经乙酰化，Ｎ－氧化，水解，Ｓａｎｄｍｅｙｅｒ反应，硝化和催化氢化合成２－氯－４－氨基吡啶。     

6-氯吡啶-3-甲醛的合成研究

以2-氯-5-氯甲基吡啶为原料,经酯化、水解、氧化3步反应合成6-氯吡啶-3-甲醛,总收率可达60％。     

2—巯基吡啶的合成及结构测定

以２－氯吡啶为原料合成２－巯基吡啶（Ⅰ），产率６０％。通过红外光谱、核磁共振和质谱对比化合物（Ⅰ）的结构进行了测试，证明合成方法的可靠性。．     

4-氯吡啶的合成研究

以吡啶为原料,经过氧化氢-醋酸氧化,硫酸置换,再用硝酸钾/浓硫酸硝化得到关键中间体对硝基吡啶-N-氧化物,再用乙酰氯作为氯化试剂氯化得到对氯吡啶-N-氧化物,最后经铁粉还原得到对氯吡啶,产物含量97.6%,总收率47.1%。     

Microwave‐Assisted Synthesis of N‐Heterocyclic Carbene‐ Palladium(II) Complexes

The microwave‐assisted synthesis of two different types of N‐heterocyclic carbene‐palladium(II) complexes, (NHC)Pd(acac)Cl (NHC=N‐heterocyclic carbene; acac=acetylacetonate) and (NHC)PdCl₂(3‐chloropyridine), has been carried out. A drastic reduction in reaction times (20 to 88 times faster, depending on the complex) was observed when compared to the previously described, conventionally‐heated synthesis of these complexes. The protocol also allowed for the synthesis of (IPr)Pd(acac)Cl [IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene] on a 5‐mmol scale in 30 min, with the reactants loaded in air.     

Hydrolysis of imidazole and 2‐chloropyridine under subcritical and supercritical water conditions

Imidazole and 2‐chloropyridine were used as model molecules to investigate the acid hydrolysis kinetics of agrochemicals in high‐temperature water in a batch reactor system at 28 MPa. Pseudo‐first‐order hydrolysis reaction rate constants for the acid hydrolysis of Imidazole and 2‐chloropyridine were determined in the temperature ranges 200–600 and 400–575°C, respectively, at 28 MPa. Rate constants for both compounds increased with temperature with a local maximum observed at around 400°C due to changes in the physical properties of the solvent. Imidazole and 2‐chloropyridine conversions of 0.95 and 0.99999 were respectively attained at the highest temperature after 30 min of reaction. © 2012 Canadian Society for Chemical Engineering     

一氯吡啶及多氯吡啶的合成与应用

介绍了各种氯吡啶化合物的合成方法及用途。     

农药中间体2—氯吡啶的光氯化合成研究

通过对吡啶光氯化的反应条件优化和化工控制,有效地控制了反应中的聚合, 焦油化等副反应,实现了反应的高转化率和高选择性.控制反应条件, 可以改变2-氯吡啶和2,6-二氯吡啶 两种产物的比例,使其中某一种产物为主.并用现代物理方法对主要产品之一的2-氯吡啶进行了结构分析,证实了这一合成方法的可靠性.     

Synthesis of Well‐Defined Diphenylvinyl(cyclopropyl)phosphine‐Palladium Complexes for the Suzuki–Miyaura Reaction and Buchwald–Hartwig Amination

The well‐defined diphenylvinylphosphine‐palladium complex 1 and the diphenylcyclopropylphosphine‐palladium complex 2 were successfully synthesized. The crystal structures of these complexes were obtained by X‐ray crystallographic analysis. Both complexes were air‐ and moisture‐stable, and could be prepared on a gram scale. These palladium complexes catalyzed the Suzuki–Miyaura reaction of aryl bromides [turnover numbers (TON) up to 196,000] and aryl chlorides (TON up to 50,000). Furthermore, complex 2 catalyzed the Buchwald–Hartwig amination of aryl chlorides and aromatic/aliphatic amines with a low catalyst loading. These complexes showed different reactivities for the coupling of 2‐chloropyridine, and the origin of this difference is discussed.     

Highly Ligand Efficient and Selective N‐2‐(Thioethyl)picolinamide Histone Deacetylase Inhibitors Inspired by the Natural Product Psammaplin A

Novel picolinamide‐based histone deacetylase (HDAC) inhibitors were developed, drawing inspiration from the natural product psammaplin A. We found that the HDAC potency and isoform selectivity provided by the oxime unit of psammaplin A could be reproduced by using carefully chosen heterocyclic frameworks. The resulting (hetero)aromatic amide based compounds displayed very high potency and isoform selectivity among the HDAC family, in addition to excellent ligand efficiency relative to previously reported HDAC inhibitors. In particular, the high HDAC1 isoform selectivity provided by the chloropyridine motif represents a valuable design criterion for the development of new lead compounds and chemical probes that target HDAC1.     

Arylethyne Bromoboration–Negishi Coupling Route to E‐ or Z‐Aryl‐Substituted Trisubstituted Alkenes of ≥98% Isomeric Purity. New Horizon in the Highly Selective Synthesis of Trisubstituted Alkenes

The hitherto unprecedented palladium‐catalyzed cross‐coupling of (Z)‐β‐bromo‐β‐arylethenylboranes can be made to proceed satisfactorily through (1) the use of highly catalytically active bis(tri‐tert‐butylphosphine)palladium or dichloro[N,N‐bis‐(2,6‐diisopropylphenyl)imidazol‐2‐yl](m‐chloropyridine)palladium and (2) conversion of the dibromoboryl group to the (pinacol)boryl group. Thus, a wide variety of carbon groups can be used to substitute bromine in ≥98% stereo‐ and regioselectivity, while suppressing the otherwise dominant β‐debromoboration. Together with the alkylethyne‐based protocols, the alkyne bromoboration–Negishi coupling tandem process has emerged as the most widely applicable and highly selective route to trisubstituted alkenes including those that are otherwise difficult to access.     

Selective indole-based ECE inhibitors: synthesis and pharmacological evaluation

Inhibition of the metalloprotease ECE-1 may be beneficial for the treatment of coronary heart disease, cancer, renal failure, and urological disorders. A novel class of indole-based ECE inhibitors was identified by high throughput screening. Optimization of the original screening lead structure 6 led to highly potent inhibitors such as 11, which bears a bisaryl amide moiety linked to the indole C2 position through an amide group. Docking of 11 into a model structure of ECE revealed a unique binding mode in which the Zn center of the enzyme is not directly addressed by the inhibitor, but key interactions are suggested for the central amide group. Testing of the lead compound 6 in hypertensive Dahl S rats resulted in a decrease in blood pressure after an initial period in which the blood pressure remained unchanged, most probably the result of ET-1 already present. Indole derivative 6 also displays a cardio-protective effect in a mouse model of acute myocardial infarction after oral administration. The more potent chloropyridine derivative 9 antagonizes big-ET-1-induced increase in blood pressure in rats at intravenous administration of 3 mg kg-1. All ECE inhibitors of the indole class showed high selectivity for ECE over related metalloproteases such as NEP and ACE. Therefore, these compounds might have further potential as drugs for the treatment of coronary heart diseases.     

Selective Covalent Protein Modification by 4‐Halopyridines through Catalysis

We have investigated 4‐halopyridines as selective, tunable, and switchable covalent protein modifiers for use in the development of chemical probes. Nonenzymatic reactivity of 4‐chloropyridine with amino acids and thiols was ranked with respect to common covalent protein‐modifying reagents and found to have reactivity similar to that of acrylamide, but could be switched to a reactivity similar to that of iodoacetamide upon stabilization of the positively charged pyridinium. Diverse, fragment‐sized 4‐halopyridines inactivated human dimethylarginine dimethylaminohydrolase‐1 (DDAH1) through covalent modification of the active site cysteine, acting as quiescent affinity labels that required off‐pathway catalysis through stabilization of the protonated pyridinium by a neighboring aspartate residue. A series of 2‐fluoromethyl‐substituted 4‐chloropyridines demonstrated that the pK_a and k_inact/K_I values could be predictably varied over several orders of magnitude. Covalent labeling of proteins in an Escherichia coli lysate was shown to require folded proteins, indicating that alternative proteins can be targeted, and modification is likely to be catalysisdependent. 4‐Halopyridines, and quiescent affinity labels in general, represent an attractive strategy to develop reagents with switchable electrophilicity as selective covalent protein modifiers.