Solid State Desemicarbazonation on Clayfen Under Microwave Irradiation

Summary.  A new, efficient, and environmentally benign method for the cleavage of semicarbazones has been achieved by a simple reaction of semicarbazones with clayfen under microwave irradiation. Received January 4, 2001. Accepted (revised) March 1, 2001     

A New Protocol for O-Methylation of Phenolic Compounds with Trimethyl Phosphite or Trimethyl Phosphate Under Solvent-Free Condition and Microwave Irradiation

A simple method for the preparation of industrially important alkyl aryl ethers is reported. Several phenolic compounds such as phenols, naphthols, and hydroxy coumarins were O-methylated with trimethyl phosphite or trimethyl phosphate under microwave irradiation and solvent-free condition in almost quantitative yields. Reaction of 2-naphthol with trimethyl phosphate gave mixture of 2-methoxynaphthalene and 1-methyl-2-methoxynaphthalene while the reaction with trimethyl phosphite gave mostly 2-methoxynaphthalene. This method is highly efficient for the methylating of phenolic compounds with very easy experimental procedure and environmental friendly conditions.     

微波干法催化环内酰胺N－烷基化反应

微波干法催化环内酰胺Ｎ－烷基化反应王存德，肖东运，张明，田兆斌，张霖（扬州大学工学院扬州２２５００１）关键词微波辐射，环内酰胺，Ｎ－烷基化，卤代烷Ｎ－烷基环内酰胺广泛应用于医药和日用化学品中［１，２］．近年来有关Ｎ－烷基环内酰胺的合成有：碱叔丁醇钾－...     

微波辐射下苯并噁唑基吡啶的合成

在微波辐射条件下,利用邻氨基酚和吡啶羧酸在多聚磷酸中的缩合反应,合成了2种苯并唑基取代吡啶 最佳反应条件为:450W辐射4min 相比于常规反应,反应时间大为缩短且产率令人满意     

2,4,6-三芳基吡啶的微波辐射促进合成

微波辐射;查尔酮;缩合反应;吡啶;叶立德     

Preparation and Characterization of Quaternized Chitosan Under Microwave Irradiation

For the first time, N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) was prepared through a fast, easy and efficient method with the assistance of microwave irradiation, and the quaternized chitosan was also degraded via the microwave irradiation. A comparative study was performed by using the conventional heating method to prepare HTCC. The structure and property of the quaternized chitosan obtained by these two methods were characterized by GPC, XRD, FTIR, NMR, TG and elemental analysis. It was shown that quaternized chitosan was successfully prepared within 50 min via microwave irradiation method, while a much longer time of 6–7 h was needed with the conventional heating method. The substitutions both occurred on the C2 position of chitosan with the two different methods, and their HTCC products had weight average similar molecular weight (Mw), structure and thermal stability. The HTCC prepared by the microwave irradiation method had a little lower degree of substitution (DS) than those prepared via conventional heating with the same mole ratio (6:1) of the intermediate to chitosan. The degradation study showed that the Mw of HTCC decreased rapidly from 4.6 × 10⁵ to 1.1 × 10⁵ in 1 h under microwave irradiation, while it only decreased from 4.6 × 10⁵ to 2.1 × 10⁵in 1 h through conventional heating degradation. These results revealed that microwave irradiation is a more efficient and environment-friendly way to obtain the water-soluble chitosan derivatives and their degraded products.     

N-烃基邻苯二甲酰亚胺的微波干法催化合成

在K2 CO3 固体碱催化下 ,利用微波辐射 ,邻苯二甲酰亚胺和卤代烃发生取代反应 ,高产率地合成了N -烃基邻苯二甲酰亚胺     

微波干法催化醛酮与胺的缩合反应

利用微波辐射和固体中性Al2 O3 载体催化醛酮与胺的缩合反应的方法合成了十六种亚胺 ,研究了微波功率、作用时间、产物提取方式等因素对反应的影响 ;与无微波作用的一般合成方法相比 ,该法明显地提高反应速度及产率 ;文中用低极性熔点递变物质灌装毛细管的方法观测微波作用下反应温度 ,探讨微波作用化学反应的机理 ,其机理除与微波加热作用有关外还与分子间氢键及分子的缔合性有关。     

微波促进催产素和赖氨加压素环肽的固相合成

以Rink Amide-MBHA树脂为载体, 采用Fmoc/tBu正交保护固相合成策略, 运用微波照射促进, 先快速高效地合成得到载有催产素或赖氨加压素还原型多肽的树脂, 再将连接在树脂上的各还原型多肽分别在微波促进条件下和常温条件下环合形成二硫键制得环肽, 最后用Reagent K试剂将环肽从树脂上裂解下来得到目标多肽的粗品. 利用HPLC法测定不同固相环合条件下得到的多肽粗品纯度, 结果显示经微波促进固相环合得到的多肽粗品纯度明显高于常温条件下得到的多肽粗品纯度. 粗品最后经过反相制备高效液相系统纯化并冻干得到目标多肽纯品, 通过电喷雾质谱法测定了制得的还原型多肽及相应环肽的分子量, 验证了它们的结构.     

微波辐射固体酸催化合成己二酸二正辛酯

采用微波辐射技术 ,以活性炭担载对甲苯磺酸为催化剂 ,由己二酸和正辛醇直接酯化合成己二酸二正辛酯。用正交试验研究了各反应因素对反应转化率的影响 ,确定其最佳反应条件为 :己二酸的用量 1mmol,正辛醇的用量 4mmol,催化剂用量为 0 .8g ,微波功率 6 0 0W ,辐射时间 45s ,转化率为 99.3 % ,催化剂且可重复使用。     

Synthesis of Unsymmetrical Ureas with Coumarin and Thiadiazole Ring Under Microwave Irradiation

A series of coumarin-3-yl substituted unsymmetrical ureas were synthesized by the reaction of 3-coumarin isocyanate, which was prepared from 3-coumarinyl azide by Curtius rearrangement, with various aromatic amines, 2-amino-5-phenyl-1,3,4-thiadiazole, and 2-amino-5-aryloxymethylene-1,3,4-thiadiazoles under microwave irradiation. Compared to conventional methods, this synthesis has the advantages of mild reaction conditions, easy handling, and high yields. The products have been characterized by analytical and spectral (IR and ¹H NMR) data.     

Synthesis of Benzofuryl Substituted Unsymmetrical Ureas Under Microwave Irradiation

A series of 2-benzofuryl substituted unsymmetrical ureas were synthesized by reactions of benzofuroyl isocyanate, which was prepared from benzofuroyl azide by Curtius rearrangement, with various aromatic amines, 2-amino-5-(benzo-2-furyl)-1,3,4-thiadiazole, and 2-amino-5-aryloxymethylene-1,3, 4-thiadiazoles under microwave irradiation. Compared to conventional methods, this synthesis has the advantages of mild reaction conditions, easy handling, and high yields. The products have been characterized by analytical and spectral (IR and ¹ H NMR) data.     

微波促进碱性离子液体催化合成查尔酮

以4-氯-1-丁醇,N-甲基咪唑和苯甲酸钠为原料,用微波法制得碱性离子液体{[OHBMIM]Ph COO(AIL)},其结构经FT-IR表征;以苯甲醛和苯乙酮为原料,AIL为催化剂,经微波促进的缩合反应合成了查尔酮(1),其结构经1H NMR和FT-IR确证。考察了AIL用量、微波功率、物料比和反应时间对1产率的影响。合成1的最佳反应条件为:AIL 1 mmol,苯甲醛5 mmol,n(苯甲醛)∶n(苯乙酮)=1.1,于微波功率140 W反应5 min,产率95.8%。AIL具有较好的循环使用性,循环使用6次,1产率没有明显降低。     

Novel Synthesis of Oxygenated Coumarins from Substituted Phenols Mediated by Vinyl Triphenylphosphonium Salt Under Microwave Irradiation

Protonation of the highly reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate(DMAD) by substituted phenols lead to vinyl triphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with a phenolate conjugate base to produce 4-carboxymethyl coumarins in fairly highly yields.     

Synthesis of 1,5-Benzodiazepines with Unusual Substitution Pattern from Chalcones Under Solvent-Free Microwave Irradiation Conditions

1,5-Benzodiazepines have been synthesized from the corresponding 2′-hydroxychalcones [1-(2-hydroxyphenyl)-3-aryl-2-propen-1-ones] and o-phenylenediamine, both in methanol, under reflux and under solvent-free microwave irradiation conditions on alumina. The latter method proved to be advantageous.     

微波辐射磷钨酸催化合成乙酸丁酯

以磷钨酸作催化剂 ,4A分子筛为脱水剂 ,采用微波辐射技术 ,用乙酸和丁醇直接合成乙酸丁酯 .考察了催化剂用量、微波辐射功率、时间、乙酸丁醇比对反应转化率的影响 .最佳反应条件为 :乙酸与磷钨酸的物质的量的比为 1∶0 .0 0 16 6 4,微波辐射功率及时间为 335W ,15min ,乙酸丁醇的物质的量的比为 1∶1.5 .此条件下转化率为 96 % .     

A Facile Synthesis of 5-Arylidene-2-imino-4-thiazolidinones Under Microwave Irradiation

A series of 5-arylidene-2-imino-4-thiazolidinone derivatives were synthesized by the cross-aldol condensation of aromatic aldehydes with 2-imino-4-thiazolidinone in sodium acetate/acetic acid under microwave irradiation. The reactions were completed in 10 min with 63–91% yields, were environmental benign, and had easy workup.     

Efficient One-Pot Synthesis of 3-Amino-7-azaindoles Under Microwave Irradiation

An efficient one-pot synthesis of 3-amino-7-azaindoles was developed, starting from ethyl (3-cyanopyridin-2-yl)carbamate and α -bromoketones by microwave-assisted Thorpe–Ziegler cyclization in the presence of a base. This method features excellent yields, short reaction time (10min), and high functional group compatibility.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

微波辐射下4,6-二羟基嘧啶与醛的反应研究

以甲胺为催化剂、醋酸为溶剂, 微波促进下芳香醛与两分子4,6-二羟基嘧啶反应得到6-羟基-5-[(4-羟基-6-氧代-1,6-二氢嘧啶-5-基)芳甲基]嘧啶-4(3H)-酮衍生物.