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.     

2-取代-4(5)-烷氧基咪唑的合成

我们曾报道了N-氰甲基苯甲亚氨酸乙酯(1a)的烷基化反应、Micheal加成和与芳醛的缩合反应。本文报道碱催化下N-氰甲基亚氨酸乙酯在醇中的成环反应结果。在固-液相转移催化条件下,N-氰甲基苯甲亚氨酸乙酯(1 a)与丙烯酸甲酯反应,生成Micheal加成产物。当用乙醇钠作碱、乙醇作溶剂时,1a与丙烯酸甲酯反应没有生成Micheal     

无碱条件下由芳香醛肟和磺酰氯制备O-磺酰基芳香醛肟

在氧化银和碘化钾存在下,磺酰氯与肟室温反应合成一系列O-磺酰基肟.芳香醛肟和酮肟作为底物,产率56%～87%.不过,对硝基苯甲醛肟、脂肪醛肟及α,β-不饱和醛肟作为该反应底物时,没有获得目标产物.     

混合三聚反应及结构的研究 Ⅰ.N,N′-二(2-羟基苄烯)芳甲二胺的新合成

醛与氨的自身三聚反应早有报道,但两种芳醛与氨直接反应,得到混合三聚产物的系统研究,尚未见报道。近年来,Takajo等人通过1与芳醛和醋酸铵反应,合成了混合三聚产物N,N’-二(2-羟基苄烯)芳甲二胺(2)。这种间接方法的产率和步骤远不如直接混合三聚反应。另外,某些取代水杨醛受取代基的影响,难以形成类似1的自身三聚产物,在合成应用上受到一定的限制。     

硝基苯和乙醇一锅法合成N-乙基苯胺

以硝基苯和乙醇一锅法合成N-乙基苯胺为例,报道了芳香硝基物和醇类化合物在一个反应器内,在相同催化剂作用下和在相同反应条件下一锅法合成N-烷基芳胺的新方法.在该方法中,醇类化合物水相重整过程中产生的氢原位地将芳香硝基物加氢还原生成芳胺,紧接着在较低的H2分压条件下,芳胺与醇发生N-烷基化反应生成相应的N-烷基芳胺.在硝基苯：无水乙醇：水的体积比为10：60：0时,在T=413K和P=1MPa条件下反应8h,硝基苯和苯胺被完全转化,N-乙基苯胺的选择性为85.9％,N,N-二乙基苯胺选择性在0-4％之间,明显优于传统的合成方法。实验结果表明,这种方法可及时地将反应过程产生的氢和芳胺从催化剂表面移走,为提高目标产物N-烷基芳胺的选择性提供了可能。     

新型杯[4]芳烃活化KOH催化合成O,O-二烷基-S-芳(烷)基磷酸酯

合成了新型杯[4]芳烃3,实验表明在杯[4]芳烃3(5.0 mol%)和KOH(20 mol%)存在下,O,O-二烷基亚膦酸酯与二芳(烷)基二硫醚的反应有效进行,较高产率得到O,O-二烷基-S-芳(烷)基磷酸酯.杯[4]芳烃3经6次重复实验后,反应产率没有明显降低.本方法避免了有恶臭气味、毒性较大的试剂的使用,为磷酸硫酯的合成提供了一条简便有效的路径.     

合成α,β-不饱和酮的一种简便方法: O,O-二乙基磷酰碲钠作用下ω-溴代苯乙酮与芳醛的反应

在O,O-二乙基磷酰碲钠存在下, ω-溴代苯乙酮与芳醛于乙醇中反应, 以良好产率生成α,β-不饱和酮.     

E/Z-焦脱镁叶绿酸-a 甲酯131-酮肟的合成及其烷(酰)基化反应

以焦脱镁叶绿酸-a 甲酯(MPP-a)为起始原料,通过E环羰基与盐酸羟胺反应,生成Z/E顺反结构的焦脱镁叶绿酸-a 甲酯酮肟异构体,分离后与酰卤和卤代烷反应,分别生成Z或者E型O-烷酰基酮肟和O-烷基酮肟.所合成新的二氢卟吩衍生物均经UV, IR, 1H NMR, 13C NMR及元素分析证实其结构.     

氨基酸合成方法研究 VI: N-氰甲基苯甲亚氨酸酯与芳醛的缩合反应

前文报道了N-氰甲基苯甲亚氨酸乙酯(1)与N-乙氧羰甲基亚氨酸酯的烷基化和Micheal加成反应。本文研究了在乙醇钠存在下,1与芳醛的缩合反应。产物α-苯甲酰氨基肉桂腈(3)是合成α-氨基酸的重要中间体。     

含磷拟除虫菊酯的研究 Ⅲ.3-烷氧羰基-2,2-二甲基环丙烷基甲醛肟或甲基酮肟和二烷氧基硫代磷酰氯的反应

本文研究了3-烷氧羰基-2,2-二甲基环丙烷基甲基酮肟或醛肟分别和二烷氧基硫代磷酰氯的反应,鉴定了它们的不同产物.结果表明,酮肟与磷酰氯缩合得硫代磷酸肟酯;醛肟与磷酰氯反应生成3-氰基环丙烷羧酸酯和相应的二烷基硫代磷酸,可能是经生成9再Beckmann裂解的机理.文中对上述结果进行了讨论.     

Ac2O/K2CO3/DMSO: an efficient and practical reagent system for the synthesis of nitriles from aldoximes

The transformation of aldoximes to nitriles using acetic anhydride as dehydration agent under mild reaction conditions is reported. The reaction, which proceeds under weak alkaline condition, allows for the conversion of a range of aldoximes including aromatic aldoximes, alphatic aldoximes, and heterocyclic aldoximes in good to excellent yields. This method has also been successfully applied to the synthesis of calcium channel blocker nilvadipine in pilot scale.     

A Convenient Conversion of Aldoximes to Nitriles Using A Polymer Supported System

Nitriles were readily prepared in excellent yields from the corresponding aldoximes and carbon disulfide under mild and non-aqueous condition in the presence of a regenerable hydroxide form of an anion exchange resin.     

One-pot sequential deoximation and allylation reactions of aldoximes in aqueous solution

A simple procedure has been developed for conducting tin-mediated deoximation and allylation reactions of aldoximes in water to form homoallylic alcohols. Employing the new conditions, various homoallylic alcohols were produced in good to excellent yields.     

An Efficient Method for the Preparation of Nitriles via the Dehydration of Aldoximes with Phthalic Anhydride

A new and highly efficient method for the conversion of aldoximes to nitriles was established. By fusing with phthalic anhydride, aldoximes were efficiently and smoothly converted into nitriles, in high yields (over 85%) and in a short time (within 5 minutes). The mixture of phthalic anhydride, a cyclic anhydride, and aldoximes in fusing state set up an ideal transition state for a selective [3.3]‐sigmatropic rearrangement of the acylated aldoximes to nitriles.     

Spectrophotometric studies,synthesis and properties of pentacyanoferrate(II) complexes with bis-quaternary pyridinium aldoximes

The colour reactions of three bis-pyridinium aldoximes with ammine- and nitrosyl-pentacyanoferrate(II) ions were studied. The optimum reaction conditions, the compositions and the stability constants of the produced complexes were determined. The compelxes were isolated and characterized by elemental analysis, visible, UV and IR spectral data. The examined compounds, although dioximes, are found to form 1 : 1 complexes.     

Iron‐Catalyzed Dehydration of Aldoximes to Nitriles Requiring Neither Other Reagents Nor Nitrile Media

The dehydration of aldoximes is an environmentally benign reaction affording the desired nitrile and water as a by‐product. However, most of the reported catalytic dehydration reactions of aldoximes require a solvent containing nitrile to synthesize the corresponding nitrile compounds. Inspired by recent reports on the enzymatic synthesis under nitrile‐free conditions, we here describe that a simple iron salt catalyzes the dehydration of aldoximes requiring neither other reagents nor nitrile media. Our method can be applied to the one‐pot synthesis of nitiriles from aldehydes.     

TETRACHLOROPYRIDINE: A NEW REAGENT FOR THE DEHYDRATION OF ALDOXIMES UNDER MICROWAVE*

ABSTRACT

Dehydration of aldoximes to nitriles using tetrachloropyridine under microwave in dry media is described. The procedure is applicable to a variety of aldoximes and the reagent can be recycled and reused.

     

Simple and Highly Efficient Procedure for Conversion of Aldoximes to Nitriles Using N-(p-Toluenesulfonyl) Imidazole

A facile and efficient method for dehydration of aldoximes into nitriles using N-(p-toluenesulfonyl) imidazole (TsIm) is described. In this method, aldoximes were refluxed with TsIm in the presence of 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU) in dimethylformamide (DMF) to afford the corresponding nitriles in good yields. This methodology is highly efficient for various structurally diverse aldoximes including aromatic, heteroaromatic, and aliphatic oximes. A plausible mechanism for the conversion of aldoxime into nitriles using TsIm/DBU is explained.     

A RAPID AND FACILE CONVERSION OF PRIMARY AMIDES AND ALDOXIMES TO NITRILES AND KETOXIMES TO AMIDES WITH TRIPHENYLPHOSPHINE AND N-CHLOROSUCCINIMIDE

ABSTRACT

Primary amides and aldoximes are easily converted to their corresponding nitriles using a mixture of triphenylphosphine and N-chlorosuccinimide in dichloromethane at room temperature. The reaction of aldoximes occurs almost immediately and primary amides in 0.5?h by this method. By this procedure secondary amides are produced by Beckmann rearrangement of ketoximes.     

Magtrieve™ (CrO2) and MnO2 mediated oxidation of aldoximes: studying the reaction course

Magtrieve™ (CrO₂) and MnO₂ mediated oxidation of aldoximes to nitrile oxides were studied in details. In presence of external radical source, TEMPO, these reagents did not furnish nitrile oxides, instead favoured deoximation to aldehydes. A common trend of deoximation was established from electronically tuned aldoximes, which is: aliphatic>aromatic>aldoximes with strong electron-withdrawing group, though the extent of deoximation was less in case of CrO₂. Above effects were not observed with chloramine-T and diacetoxyiodobenzene, reagents known to produce nitrile oxides via hydroximoyl halide or equivalent ionic intermediates. A putative reaction mechanism is proposed for MO₂ (M=Cr, Mn) mediated oxidation of aldoximes through formation of a nitroso-oxime tautomeric pair. Formation of nitrile oxide is possibly occurred from the oxime tautomer via a σ-type iminoxy radical intermediate. The deoximation process, dominating in presence of external radical environment, is explained following decomposition of the nitroso tautomer.