超声辐射下一锅法制备O-芳磺酰基芳醛肟

在超声辐射和NaOH存在下,由芳醛肟与芳基磺酰氯在室温CH2Cl2中反应15~60 min生成相应的O-芳磺酰基芳醛肟,收率56%~94%.操作简便,反应条件温和,时间短,产率高.     

TS-1/H_2O_2体系催化香茅醛肟化反应

将TS-1/H2O2催化体系用于催化香茅醛氨肟化制备香茅醛肟反应中,结果表明,在优化的反应条件下,香茅醛转化率和香茅醛肟选择性分别达99.9%和99.2%以上.反应过程中主要存在两对竞争反应:TS-1催化的醛肟化反应和碱催化的羟醛缩合反应;TS-1催化的醛肟化反应和双键环氧反应.通过调节体系中氨含量可有效抑制副反应.     

α-苯磺酰基环十二酮肟酯的合成及其除草活性

以环十二酮为原料, 经过α-取代反应生成中间体α-苯磺酰基环十二酮, 先与NH2OH作用成肟然后酯化反应合成了20个未见文献报道的α-苯磺酰基环十二酮肟酯衍生物(8), 其化学结构经1H NMR, IR和元素分析确证. 初步生物活性测定结果显示, 部分化合物具有一定的除草活性, 如α-苯磺酰基环十二酮肟-2,4-二氯苯氧乙酸酯(8p)在浓度为100和1 mg/L时对马唐(Digitaria sanguinalis)的抑制率分别为100%和80.07%; 对苘麻(Abutilon theophrasti)的抑制率分别为100%和88.70%. 毒力测定结果显示, OE16对马唐的IC50值和苘麻的IC50值分别为0.192和0.151 mg/L.     

低价钛引起的芳香醛肟的还原偶联反应

低价钛引起的芳香醛肟的还原偶联反应史达清周龙虎高原戴桂元（徐州师范大学化学系２２１００９）低价钛试剂在有机合成上的应用越来越受到人们的广泛重视。它能引起一元醛、酮和二元醛、酮发生脱氧偶联反应生成烯烃、环烯烃和杂环烯烃［１］。此外，低价钛还能引起其他官...     

铑催化苯醌磺酰化反应合成磺酰基醌类衍生物

报道了一种过渡金属铑催化的醌类与磺酰氯化合物的偶联反应,实现了醌类的磺酰化反应.在温和的反应条件下,以较高的产率成功合成了一系列具有生物活性的磺酰基醌类化合物,此反应不仅对苯醌具有较好的适应性,对于萘醌底物也能取得较高的产率,并提出了初步的反应机理.     

有机硒催化肟转化为腈或酮

1-氟吡啶三氟甲烷磺酸盐(FP-OTf)和二苯基二硒醚在空气中反应生成苯次硒酸和苯亚硒酸,这种混合物可以催化醛肟和酮肟分别转化腈或酮.通过改变二苯基二硒醚的用量及其与FP-OTf的物质的量之比,能够提高以上两类反应的催化效果.当二苯基二硒醚用量为5 mol%, FP-OTf的用量为4 mol%时,可以催化醛肟以较高的产率转化为腈(57%～94%),而在酮肟转化为酮的反应中,二苯基二硒醚的用量为2.5 mol%,且与FP-OTf的物质的量之比为1∶1.2时,产率较高(74%～91%).     

加料方式及底物浓度对Ti-MWW催化剂上环己酮氨肟化反应的影响

 研究了加料方式和底物浓度对钛硅分子筛Ti-MWW催化环己酮液相氨肟化反应的影响. 结果表明,加料方式对 Ti-MWW 催化环己酮氨肟化过程有重要影响,过氧化氢的浓度对反应过程也有一定的影响. 在过氧化氢缓慢加入反应体系的情况下,环己酮转化率和环己酮肟选择性都高于99%, 而且该反应过程以水作溶剂,对环境友好.     

N-取代-5-磺酰基吡唑肟醚衍生物的合成及生物活性研究

以吡唑酮、盐酸羟胺、硫酚、2-氯-5-氯甲基吡啶等化合物为原料,设计合成了5个未见文献报道的磺酰基吡唑肟醚新化合物,其结构经元素分析、1HNMR、IR和MS验证。初步生物活性测试表明,部分化合物具有一定的杀菌活性。     

磺酰氯与不饱和化合物的反应

磺酰氯是一类重要的有机合成中间体,广泛应用于有机和药物合成中。磺酰氯可以作为烯砜、磺酰基、次磺酰基、芳基、氟代烷基等的来源应用于多种有机合成反应中。本文综述了磺酰氯与烯烃、炔烃、(杂)芳香环、亚胺、卤代醛酮等不饱和化合物的反应,主要包括[2+2]环合反应、氯磺酰化、磺酰化、次磺酰化、芳基化和氟代烷基化等反应,并讨论和预测了磺酰氯与不饱和化合物反应今后的发展方向。     

SiO2担载聚甲酚磺醛作为固体酸催化剂用于有机反应

均相催化多相化是催化化学研究热点之一.但是,很多固体催化剂的制备需要专门的仪器设备和长期的实验技术积累,而一般的有机合成化学实验室并不具备制备和调控固体催化剂的条件.另外,部分固体催化剂制备过程较为复杂,制备周期较长,因此,人们在进行有机转化反应操作时往往倾向于采用均相催化剂.为了改变这一现状,需要尽快发展制备方法简单、周期短、性能可靠的固体催化剂,以期能够在当前化学反应绿色化过程中做出更大贡献.酸催化剂广泛用于有机合成反应.传统硫酸、氢氟酸等均相酸催化剂虽然催化活性较好,但其腐蚀性强、毒性大,且回收困难.为了提高化学转化过程的绿色性,固体酸催化剂在有机反应中的应用已广受关注.但是,传统的固体酸催化剂制备过程大多较为复杂,获取周期长,且酸度不均、负载量也难以实现调控,因此有必要发展一种制备便捷、酸度适中、普适性广的固体酸催化剂.聚甲酚磺醛是2-羟基-4-甲基苯磺酸与甲醛的低聚物,不溶于二氯甲烷、乙酸乙酯等大部分有机溶剂,易溶于水.聚甲酚磺醛的水溶液已经被用作治疗妇科疾病的药物,是一种廉价、易得、生物兼容性好的市售化学品.由于聚甲酚磺醛分子结构中含有大量的磺酸基,因此其具备作为酸催化剂的潜质.考虑到其骨架结构中富含大量羟基,可能与SiO2类多羟基载体产生氢键作用,因而可在一定程度上稳定制备的SiO2/聚甲酚磺醛复合固体材料.本文采用浸渍法,经如下两步将聚甲酚磺醛负载于SiO2表面,制备了一系列担载量不同(0.2~1.5 mmol/g)的复合酸性材料：(1)将SiO2加入聚甲酚磺醛水溶液的乙醇溶液中,在室温下磁力搅拌10–15分钟;(2)在减压条件下除去水和乙醇(约30分钟).整个制备过程,无需专门的设备,仅需使用磁力搅拌器和旋转蒸发仪等一般有机合成实验室的常规仪器,并且制备周期非常短,在1小时以内即可完成.该方法所制备催化剂的负载量可由投料比直接控制,可简单、快速制备负载量不同的SiO2/聚甲酚磺醛复合固体材料.研究发现, SiO2/聚甲酚磺醛复合固体催化剂能够高效地促进多种有机反应,如二苯甲醇与苯乙烯衍生物的亲核取代反应、2-苯基乙醇与醛的oxa-Pictect-Spengler反应以及吲哚与1,3-二羰基化合物或2-苯基乙醛的直接C3-烯基化反应.在上述反应中,目标产物的产率均较高,且反应对底物具有良好的官能团兼容性. SiO2/聚甲酚磺醛催化剂均可重复使用多次,且催化活性无明显下降.更重要的是,上述反应的投料量可增加至10 mmol,且产物的分离产率无明显下降,从而证明SiO2/聚甲酚磺醛催化剂具有一定的实际合成价值.值得一提的是,由于SiO2/聚甲酚磺醛催化剂含有一定量的水,本文认为聚甲酚磺醛在SiO2表面是以水溶液的形式存在,因此在反应过程中可能是以均相催化的方式进行.相较于传统的SiO2负载磺酸、TiO2负载苯磺酸以及Amberlyst-15催化剂, SiO2/聚甲酚磺醛复合固体酸催化剂具有活性高、制备周期短、廉价易得的特点.同时,该催化剂可简单、快速制备各种不同酸负载量的固体催化剂,在一定范围内调控该类固体酸催化剂的酸性.因而, SiO2/聚甲酚磺醛复合固体酸催化剂望用于各种酸催化合成反应中.     

Dehydration of Aryl Aldoximes

The conversion of aldoximes into nitriles is a well known, straightforward and important organic operation which may be brought about by the action of common dehydrants such as acetic anhydride¹ and mesyl chloride^2. This paper describes a new method of effecting the reaction.     

某些芳环醛肟的烷基化反应

近年来分子内1,3-偶极环加成反应引起了较大的注意,它被用来合成某些杂环、多环以及结构复杂的天然产物,为了解决中间体问题,我们摸索了某些芳环醛肟(N-4-戊烯基)氮酮Nitrone的合成方法.通常,醛肟与活泼的卤代烃作用得到N-烷基化产物和O-烷基肟.某些碘代烃对光敏感,不很稳定,产率较低,我们采用溴代烃,方法简便,产率较高.表1给出某些芳环醛肟的烷基化产物,从中看出,Z型肟(1,4,7,12,17,20)主要生成N-烷基化产物,N/O比值为4.73-6.80;E型肟(10,15)主要生成O-烷基肟(11,16),N/O比值为0.14-0.15。     

Mechanochemical Dimerization of Aldoximes to Furoxans

Solvent-free mechanical milling is a new, environmentally friendly and cost-effective technology that is now widely used in the field of organic synthesis. The mechanochemical solvent-free synthesis of furoxans from aldoximes was achieved through dimerization of the in situ generated nitrile oxides in the presence of sodium chloride, Oxone and a base. A variety of furoxans was obtained with up to a 92% yield. The present protocol has the advantages of high reaction efficiency and mild reaction conditions.     

The Electrochemical Investigation of Certain Bis-Pyridiniom Aldoximes

Abstract

Bis-pyridinium aldoximes reactivate inhibited cholinesterases poisoned by organophosphorous insecticides; 4-carbamoy 1–2′-hydroximinomethyl-bis (1-pyridinomethyl) ether dichloride is presently being investigated as an antidote for this type of phosphate ester poisoning. Current chromatographic detection methods for this compound and its metabolites, at levels present in biological samples, lack both sensitivity and selectivity. The electrochemical properties of these compounds were studied in both aqueous and non-aqueous media in order to establish a suitable electrochemical detection strategy for use after separation by high pressure liquid chromatography.     

Mass Spectra of Furfuryl Aldoximes and Ketoximes

The mass spectra of 8 furfuryl aldoximes and ketoximes were studied under EI and CI conditions. Complicated fragmentation patterns were obtained in EI conditions, including formation of a furfuryl cation radical, furfuryl cation, and [M-17]⁺. The relatively simple patterns of cleavage resulted in few major ion peaks contributed from the adducts, protonation products, and dehydration products under CH₄-CI and NH₃-CI conditions. Comparison with the spectra of their isomeric amides indicated no evidence that the isomerization took place from oximes before fragmentation in both ionization methods.     

Oxidative Conversion of Aldoximes into Carboxylic Acid Esters

Aromatic and aliphatic aldoximes or their O-methyl ethers can be efficiently converted into the corresponding carboxylic acid esters by treatment with an alcoholic solution of 30% hydrogen peroxide in the presence of catalytic amounts of 2-nitrobenzeneseleninic acid. Primary alcohols give excellent to good yields, secondary ones - good to moderate, but with tertiary alcohols no esterification is obserwed.     

Dehydration of Aldoximes by Dichlorocarbene in Reverse Micelle

The use of reverse micelle to catalyze the dehydration, on a preparative scale, of aldoximes to nitriles by dichlorocarbene is reported.     

Electrochemical Activation of Nitromethane to Construct Isoxazoline Aldoximes

Activation of nitromethane to endow new reactivity is an interesting and meaningful but also challenging topic. Herein, we report an electrochemical activation of nitromethane to serve as both the heterocyclic skeleton and oxime sources for the construction of isoxazoline aldoximes. The isoxazoline aldoximes that are prepared by four steps with the reported strategy are synthesized in a single step from low-cost and readily available nitromethane and olefins with moderate to excellent yields under our electrochemical conditions. The reaction also takes advantage of high atom-economy and E-selectivity. Moreover, the mechanism is studied by control experiments, a kinetic isotope effect (KIE) study, cyclic voltammogram (CV) experiments, and density functional theory (DFT) calculations. The mechanistic results reveal that nitromethane may be activated under electrochemical conditions to deliver a 1,2,5-oxadiazole 2-oxide intermediate, which undergoes [3+2] cycloaddition with olefins to yield isoxazoline aldoximes.     

超声辐射下水溶液中芳醛肟的合成

在没有催化剂条件下, 芳香醛与盐酸羟胺的水溶液经超声辐射于室温反应, 可以72%～98%收率得到肟. 该方法具有操作简便、反应条件温和、反应时间短、对环境友好等优点.     

A Convenient Synthesis of α-Hydroxyiminoacetonitriles From Aldoximes

Aromatic α-hydroxyiminoacetonitriles can be conveniently prepared by a facile one-pot procedure in high yields involving chlorination of the corresponding aldoximes with tert-butyl hypochlorite followed by reaction with alkali cyanide.