水热法简单高效合成三聚氰酸

以三聚氰胺为原料,通过热聚合和水热处理,简单高效地合成了三聚氰酸。 通过用X射线单晶衍射(XRD)、核磁共振波谱仪(NMR)、傅里叶变换红外光谱仪(FTIR)、质谱和元素分析仪对产物进行了结构表征。 在最优的水热反应温度140 ℃下,反应2 h,总产率可达54%。 该合成方法工艺简单,污染少,为工业制备三聚氰酸提供了一种新的参考方案。     

Efficient Route for the Synthesis of Highly Substituted Pyrroles

A mild and efficient synthesis of highly substituted pyrroles using the reaction of triphenylphosphine, α-diketone, ammonium acetate, and dialkyl acetylenedicarboxylates is described.     

Efficient and Green Method for the Synthesis of Highly Substituted Cyclohexadiene Derivatives in Aqueous Media

Three-component reaction of aromatic aldehyde, malononitrile, and 2-(1-(3-chlorophenyl)propylidene)malononitrile in aqueous media catalyzed by tetraethylbenzylammonium chloride (TEBAC) at 90 °C gave 2-amino-6-(3-chlorophenyl)-5-methyl-4-arylcyclohexa-1,5-diene-1,3,3-tricarbonitrile derivatives. The structure of 4e was further confirmed by x-ray diffraction. This three-component reaction had the advantages of green solvent, good yield, and operational simplicity.     

高效且环境友好的催化剂—CMC负载稀土催化剂在一锅法合成咪唑类衍生物中的应用

CMC负载稀土催化剂是由CMC和异丙氧基稀土制得。这种固体Lewis酸催化剂被用在比较温和的条件下合成取代的咪唑类化合物。相比于昂贵的稀土Lewis酸Ln(OTf)3，廉价的CMC负载稀土催化剂也显示出了很高的催化活性。此外，这种催化剂还具有易于回收和重复使用五次以上没有明显失活的优点。     

Highly Efficient Solvent-Free Synthesis of Dihydropyrimidinones Catalyzed by Zinc Oxide

A simple, efficient and practical procedure for the Biginelli reaction using zinc oxid (ZnO) as a novel and reusable catalyst is described under solvent-free conditions in high yields. The use of this agent is characterized by remarkable reactivity, moderate costs, low toxicity and simple work up procedures.     

Simple and Convenient Method for the Synthesis of Aryltellurophosphates Catalyzed by Cesium Hydroxide

In the presence of a catalytic amount cesium hydroxide, the corresponding aryltellurophosphates can be obtained by the reactions of dialkyl phosphites with diaryl ditellurides in excellent yield at room temperature, using dimethylsulfoxide as solvent. The possible reaction mechanism was discussed. The method could provide a new and expedient path for the preparation of aryltellurophosphates.     

Efficient and Convenient Method for the Synthesis of Symmetrical Triindolylmethanes Catalyzed by Iodine

Indoles reacted with triethyl orthoformate in the presence of a catalytic amount of iodine at room temperature to give the corresponding symmetrical triindolylmethanes (TIMs) in good to high yields.     

Highly Efficient Gold‐Catalyzed Synthesis of Dibenzocycloheptatrienes

Dibenzocycloheptatrienes are obtained by a gold‐catalyzed 7‐exo‐dig hydroarylation protocol in a highly efficient manner. The gold‐catalyzed reaction usually gives the products in high yields and excellent selectivity. This procedure provides an easy and efficient access to dibenzocycloheptanoids, which are an interesting and unique class of natural products. This was underlined by the first total synthesis of reticuol.     

Efficient Multi‐component Synthesis of Highly Substituted Imidazoles Utilizing P2O5/SiO2 as a Reusable Catalyst

Phosphorus pentoxide supported on silica gel (P₂O₅/SiO₂) has been used as an efficient and reusable catalyst for the one‐pot pseudo four‐component synthesis of 2,4,5‐trisubstituted imidazoles from benzil or benzoin, aldehydes, and ammonium acetate. It was also used for four‐component preparation of 1,2,4,5‐tetrasubstituted imidazoles from benzil or benzoin, aldehydes, primary amine, and ammonium acetate under thermal solvent‐free conditions. The remarkable features of this new procedure are high conversions, cleaner reaction, simple experimental and work‐up procedures and also the catalyst can be easily separated from the reaction mixture and reused several times without any loss of its activity.     

硅烷偶联化壳聚糖负载CuBr高活性催化合成1,2,3-三唑化合物

以壳聚糖为原料,将其与N-(2-氨乙基)-3-氨丙基三乙氧基硅烷(AAPTS)反应制得胺基功能化的壳聚糖(CS-AAPTS),然后将CS-AAPTS与Cu Br进行络合制备得到负载型催化剂(CS-Cu Br).通过FT-IR,TGA,XRD以及EDX等分析方法对CS-Cu Br催化剂进行表征.结合微波辐射技术以及"一锅法"合成策略,以CS-Cu Br为催化剂催化有机炔、卤代烷以及Na N3之间的环加成反应制备1,2,3-三唑.结果表明,CS-Cu Br具有良好的催化性能,微波辐射功率为480W,温度为70℃条件下,可快速合成出1,2,3-三唑类化合物.CS-Cu Br易回收和重复使用,重复使用4次后仍可保持良好收率.初步放大实验表明,1,2,3-三唑类化合物能够以94%的收率以十数克规模制备.     

Highly Efficient and Regioselective Platinum(II)‐Catalyzed Tandem Synthesis of Multiply Substituted Indolines and Tetrahydroquinolines

A special advantage : The platinum(II)‐catalyzed tandem cyclization of aminoalkynes with 1,3‐diketones offers a new and highly efficient method for the synthesis of indolines and tetrahydroquinolines (see scheme; M.S.=molecular sieves). This transformation affords good to excellent product yields with high regio‐ and chemoselectivity under mild reaction conditions.

     

Highly Efficient Synthesis of Bis（indolyl）methanes Catalyzed by Sodium Tetrafluoroborate

Sodium tetrafluoroborate （NaBF4） was found to catalyze the electrophilic substitution reactions of indoles with aldehydes and ketones under solvent-free conditions to afford the corresponding bis（indolyl）methanes in high yields.     

Schiff碱功能化壳聚糖负载CuBr高效催化合成1,2,3-三唑化合物

以壳聚糖为原料,在乙醇溶液中通过将其与2-吡啶甲醛反应制得Schiff碱功能化的壳聚糖(PYCS),然后将PYCS与Cu Br进行络合反应制得负载型催化剂(PYCS-Cu Br).采用红外光谱、热重分析和X射线衍射分析等方法对PYCS-Cu Br催化剂进行表征.热重分析结果表明,该催化剂在200℃以内具有较好的热稳定性,能够满足其使用温度.结合微波辐射技术以及一锅法合成策略,以PYCS-Cu Br为催化剂催化有机炔、卤代烷以及Na N3之间的环加成反应.结果表明,PYCS-Cu Br催化剂具有良好的催化性能,在微波辐射功率为480 W,温度为70℃条件下,15 min可快速制得1,2,3-三唑类化合物,该催化剂易回收,且可重复使用至少4次,活性未见明显降低.放大反应结果表明,1,2,3-三唑类化合物能够以较高收率并以数十克规模制备.     

Highly Enantioselective Rhodium‐Catalyzed Addition of Arylboroxines to Simple Aryl Ketones: Efficient Synthesis of Escitalopram

Highly enantioselective additions of arylboroxines to simple aryl ketones have been achieved for the first time with a Rh/(R,R,R,R)‐WingPhos catalyst, thus providing a range of chiral diaryl alkyl carbinols with excellent ee values and yields. (R,R,R,R)‐WingPhos has been proven to be crucial for the high reactivity and enantioselectivity. The method has enabled a new, concise, and enantioselective synthesis of the antidepressant drug escitalopram.     

水相铜/十二烷基取代酰肼-吡啶-N-氧化物催化咪唑的N-芳基化

设计合成了5种新型烷基取代酰肼-吡啶-N-氧化物,并将其作为水相铜催化含氮杂环与芳香碘代物偶联反应的配体.实验结果表明,十二烷基取代酰肼-吡啶-N-氧化物的催化效果最佳.对影响反应的其它条件,如铜源、碱、反应时间和温度等条件进行了优化,建立了最佳反应条件:CuO(10%,摩尔分数),NaOH(1 mmol),TBAB(5%,摩尔分数),L5(20%,摩尔分数),于120℃反应12 h,无需惰性气体保护.在此条件下,芳香碘代物与咪唑偶联反应的产率为60%~92%.该方法的特点是以水作为反应溶剂,长链烷基取代酰肼-吡啶-N-氧化物同时起到了铜催化剂配体和相转移催化剂的作用.     

Polystyrene-supported Benzyl Selenide: An Efficient Reagent for Highly Stereocontrolled Synthesis of Substituted Olefins

Solid-phase methodology has been rapidly and extensively applied to the preparation of small organic molecules recently1. It might be argued that selenoxide syn-elimination provided the principal impetus for the development of organoselenium chemistry. In addition, the required selenoxides are readily available from the oxidation of the corresponding selenides, which in turn can be prepared by the reaction of selenium-stabilized carbanions with various electrophilic substrates2. However, or…