A Facile Preparation of Organyltellurophosphates

Abstract

Organyltellurophosphates can be synthesized smoothly via the free radical reaction of diorganyl phosphites with diorganyl ditellurides using (diacetoxyiodo)benzene and sodium azide in moderate to good yields.     

A Facile Preparation of 2-Arylethenephosphonates

Vinylphosphonates 3 could be prepared with E-selectivity by the condensation of diethyl methylphosphonate 1 with a series of carbonyl compounds using diethyl chlorophosphate.     

A Facile Preparation of N2-Arylisocytosines

N²-Arylisocytosines were obtained in good yields varying from 59 to 96% by a simple two-step process starting from 2-thiouracil via readily accessible 2-(methylthio)pyrimidin-4(3H)-one.     

A Facile Method for the Preparation of Cyclic Trithiopyrophosphate

Cyclic trithiopyrophosphates can be prepared from the reaction of alkali metal dithiophosphates or pyridinium dithiophosphates with 2-bromo-1-methylpyridinium iodide in high yields under mild and efficient conditions.     

Facile Preparation of 1,2-Diketones

Easily accessible lead-like libraries of heterocyclic molecules useful for high-throughput screening are of continuous interest to the pharmaceutical industry. A number of drug-like libraries are derived from aromatic 1,2-diketones; however, nonsymmetrical 1,2-diketones are challenging to prepare. This communication describes a simple and practical synthesis of 1,2-diketones based on a controlled cross benzoin-like condensation reaction.     

A Facile Synthesis for the Preparation of Alkylamidothiophosphate - Potassium

Abstract

The reaction of 0.0-dialkyl-alkylamido-thiophosphates with potassium hydroxide without a solvent is strong exotherm. The products formed with nearly quantitative yield are the corresponding alkylamidothiophosphate-potassium (1):     

A Mild,Facile Method for the Preparation of Amino-esters

Lithium alcoholates prepared in situ react spontaneously with imidazolides derived from substituted aromatic carboxylic acids to provide the amino-esters 4 in excellent yield.     

A Facile Preparation of Tebbe Reagent and its Subsequent Reactions

A facile preparation of Tebbe reagent (1) by reacting AlMe₃ solution with Cp₁TiCl₂ is reported. After complete removal of solvent and excess of AlMe₃, the crude Tebbe reagent could be used without purification to react with ketones in a Wittig-type manner.     

简单方法制备羟基磷灰石中空微球

无需添加任何有机物和金属离子, 以易得的中空球形碳酸钙(CaCO3)与磷酸氢二钠(Na2HPO4)作为反应物在常压下制备出羟基磷灰石中空微球. 通过场发射扫描电子显微镜(FESEM)、扫描电子显微镜(SEM), X射线粉末衍射(XRD)等手段对制备的羟基磷灰石中空微球的结构、组成和形貌进行了表征, 考察了不同反应温度对中空球形貌的影响. 实验结果表明, 所制备的羟基磷灰石微球是由短针状的纳米粒子组成的, 直径为2-4 μm. 对反应机理进行了初步探讨.     

Surface-Mediated Hydrohalogenation of Isoprene: A Facile Preparation of Prenyl Halides

Abstract

The reaction of isoprene with SOCl₂ (0.5 mol equiv.) or PBr₃ (0.4 mol equiv.) or PI₃ (0.4 mol equiv.) in the presence of SiO₂ at ?10°C produced prenyl chloride (82%), or bromide (70%) or iodide (65%), respectively, in less than 30 min reaction time.     

A Facile Preparation of the Co3O4 Villiform Nanostructure

A Co₃O₄ villiform nanostructure was prepared by the aid of the cobalt oxalate precursor and characterized with x-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and UV-vis spectrum. It is found that the villiform structure obtained consists of Co₃O₄ nanorods with diameters of 50–80 nm. Moreover, the UV-vis absorptions of the villiform Co₃O₄ show the apparent blue shifts by comparison with the bulk Co₃O₄, indicating a quantum size effect similar to the free Co₃O₄ nanoparticles.     

海藻酸改性的中空SiO2微球的简易制备及应用

以CaCO3为模板,正硅酸四乙酯（TEOS）为硅源,用比较简单的方法制备了中空SiO2;然后将海藻酸钠嫁接在氨基化的中空SiO2表面;再利用海藻酸盐与钙离子的作用,在中空SiO2表面形成一个凝胶化层,制得海藻酸盐凝胶化的中空SiO2微球,粒径为1~2 μm。 采用FTIR、XRD、SEM、TEM和TGA等测试技术对微球进行表征。 此微球成功地用于柔红霉素的载负和缓释,最大载负率和载药量分别为55.6%和27.8%;缓释结果表明,海藻酸盐凝胶化层的存在,能更有效控制柔红霉素缓慢的释放,这种凝胶化载体对药效强、毒性较大的药物有潜在的临床应用前景。     

A Facile Method for the Preparation of S-(Alkylsulfenyl)cysteines

A general method for the facile preparation of S-(alkylsulfenyl)cysteines is described. It employs S-(methoxycarbonylsulfenyl)cysteine hydrochloride [H-Cys(Scm)-OH.HCl] as an easily accessible parent thiolactivated cysteine derivative.     

Activation of Hemiaminal Ethers by Chiral Brønsted Acids for Facile Access to Enantioselective Two‐Carbon Homologation Using Enecarbamates

An enriching experience : Chiral phosphoric acids have been used to catalyze the title transformation for aromatic and aliphatic hemiaminal ethers. The process affords the corresponding products in good to high enantioselectivity (see scheme; Boc=tert‐butoxycarbonyl, G=aromatic group). The method enables facile access to highly enantioenriched 1,3‐diamine derivatives.

     

New Facile Preparation of Dihydro Spiro-1,5-benzodiazepines

2,3-Cycloalkano-3,4-dihydro(5H)-7-benzoyl-1,5-benzodiazepine-4-spirocycloalkanes have been prepared from 4-benzoyl-o-phenylenedi-amine and cycloalkanones in presence of acetic acid. Only in the case of cyclohexanones, dihydrospiro benzimidazoles are formed as coproducts which are absent in others.     

Facile Preparation and Application of Polystyrylsulfonyl Chloride Resins

Polystyrylsulfonyl chloride resin (1) is a useful polymer intermediate in organic syntheses. Resin 1 can be obtained by chlorosulfonation of styrenedivinylbenzene copolymers, or treatment of the sulfonated copolymer derivatives (i. e., sulfonic cation exchange resins) with thionyl chloride, phosphorus oxychloride and phosphorus pentachloride. The preparation of polystyrylsulfonyl chloride have been reviewed by Emerson et al.     

Facile Preparation of a Butane-2,3-Dione Monoketal

Butane-2,3-dione and 2,2-dimethyl-propane-1,3-diol react, under the influence of an acidic ion exchange catalyst, to produce the monoketal in high yield.     

trans-Selective Aryldifluoroalkylation of Endocyclic Enecarbamates and Enamides by Nickel Catalysis

Efficient methods for the dicarbofuntionalization of the cyclic alkenes 2-pyrroline and 2-azetine are limited. Particularly, the dicarbofunctionalization of endocyclic enecarbamates to achieve fluorinated compounds remains an unsolved issue. Reported here is a nickel-catalyzed trans-selective dicarbofunctionalization of N-Boc-2-pyrroline and N-Boc-2-azetine, a class of endocyclic enecarbamates previously unexplored for transition metal catalyzed dicarbofunctionalization. The reaction can be extended to six- and seven-membered endocyclic enamides. A variety of arylzinc reagents and bromodifluoroacetate, and its derivatives, undergo the reaction, providing straightforward and efficient access to an array of pyrrolidine- and azetidine-containing fluorinated amino acids and oligopeptides, which may have applications in the life sciences.