Chlorination and Bromination of Dialkyl Tellurides

The reactions of dialkyl tellurides R₂Te (R = C₂H₅, n‐C₃H₇, i‐C₃H₇, c‐C₆H₁₁) with sulfuryl chloride and bromine were examined. The dialkyltellurium(IV) dichlorides (C₂H₅)₂TeCl₂ ( 1 ), (n‐C₃H₇)₂TeCl₂ ( 2 ), (i‐C₃H₇)₂TeCl₂ ( 3 ) and (c‐C₆H₁₁)₂TeCl₂ ( 4 ) were obtained upon reaction with stoichiometric amounts of SO₂Cl₂. Excess of SO₂Cl₂ resulted in formation of mixtures of R₂TeCl₂ and RTeCl₃. Treatment of (C₂H₅)₂Te and (n‐C₃H₇)₂Te with excess bromine gave the dialkyltellurium(IV) dibromides (C₂H₅)₂TeBr₂ ( 5 ) and (n‐C₃H₇)₂TeBr₂ ( 6 ), whereas (i‐C₃H₇)₂Te and (c‐C₆H₁₁)₂Te yielded the alkyltellurium(IV) tribromides i‐C₃H₇TeBr₃ ( 7 ) and c‐C₆H₁₁TeBr₃ ( 8 ). Equimolar amounts of bromine resulted in mixtures of R₂Te and RTeBr₃. All products were identified and characterized by analytical and spectroscopic methods. n‐Propyl tellurium tribromide ( 9 ) was detected from a solution of the dibromide 6 after prolonged periods. The crystal structures of 7 , 8 and 9 were determined.     

Studies on the Selective Syntheses of Sodium Ditelluride and Dialkyl Ditellurides

Studies on the selective synthetic method for dialkyl ditellurides 1, a representative class of organyl tellurium compounds, were presented. Considering the difficulty in conducting previous harsh reactions and in suppressing the formation of dialkyl tellurides 2 as side products, we optimized reaction conditions for selective syntheses of sodium ditelluride and the corresponding dialkyl ditellurides 1. We reduced tellurium to sodium ditelluride by using NaBH₄ and subsequently, treated the obtained sodium ditelluride with alkyl halides (RX) to give the target compounds 1. Consequently, by applying various alkyl halides (RX) we achieved the selective syntheses of dialkyl ditellurides 1 (13 examples with 4 new compounds) in modest to good yields. We also suggested the mechanistic pathways to dialkyl ditellurides 1.     

A Novel Synthesis of Unsymmetrical Diaryl Ditellurides

Sodium aryl tellurolates react with aryltellurenyl iodides in dry THF at room temperature to form unsymmetrical diaryl ditellurides in excellent yields.     

邻芳基苯基膦酸酯的新合成路线

以磷酸苯酯为原料,经碱性重排、O-磺酰化和Suzuki偶联反应合成邻芳基苯基膦酸酯是一条方便合理的路线.     

A New Route for Synthesis of Entecavir

2-Amino-1,9-dihydro-9-[(1S,3R,4S)-4-hydroxy-3-(hydroxymethyl)-2-methylenecyclopen tyl]-6H-purin-6-one (entecavir, Scheme 1) is a novel carbocyclic 2-deoxyguanosine analog drug which has potent and selective anti hepatitis B virus (HBV) activity1-3. Entecavir is also effective against lamivudine-resistant YMDD mutants4. The US Food and Drug Administration (FDA) approved entecavir as a new preferred drug for the treatment of HBV after lamivudine in March, 2005. Scheme 1 The structure o…     

1'-碘代二茂铁甲醛合成的新方法

二茂铁甲醛是有机合成化学中一个重要的中间体,利用它可以合成各种功能二茂铁衍生物.然而异环取代的二茂铁甲醛因合成难度较大使其应用受到限制,1'-碘代二茂铁甲醛分子内因为有较多的反应活性点,从而被广泛应用到功能金属有机分子的设计合成中.合成该物质的传统方法不仅路线长,且需要使用昂贵的金属有机试剂.我们利用改进后的合成方法,以二茂铁为起始原料经三步反应合成了1'-碘代二茂铁甲醛.该方法不仅缩短了合成路线,简化了反应条件,且避免使用苛刻的反应条件和贵重的有机锂(锡)试剂,是目前合成该化合物最简单的方法.     

A New Route for the Synthesis of Substituted Pyridazines

Condensation of 4‐acetyl‐5,6‐diphenyl‐2,3‐dihydropyridzin‐3‐one (1) with dimethylformamide dimethylacctal (DMFDMA) afforded the enaminone 2. This could be converted into the pyrazolylpyridazine derivative 4 on reaction with hydrazine hydrate and into pyridazinylpyridazinone 7a,b via coupling with aromatic diazonium salts and subsequent treatment with active methylene compounds. The reaction of 6 with dimethyl acetylenedicarboxylate in the presence of triphenylphosphine afforded the pyridazinylpyridazine derivative 8. Compound 1 converted into 9 upon reflux in acetic acid in the presence of ammonium acetate and afforded 10 on reflux in acetic acid.     

二茂铁基α—二酮合成的新途径

本文报道根据Corey和Seebach“羰基反应活性逆转”原理合成二茂铁基α-二酮的新途径。用锂化二茂铁基二噻烷与一个酯反应,再经HgCl_2-CdCO_3水解得到标题化合物。共合成16种酰基二茂铁基二噻烷和13种二茂铁基α-二酮化合物。除两种外,其余均为新二茂铁衍生物。所有产物的结构都由元素分析、IR和~1H NMR谱确定。本文讨论了反应中二茂铁衍生物在结构及性质上的特点和产物的IR和~1H NMR谱。     

A New Route for the Synthesis of N-Substituted Diketopiperazine Derivatives

Eight N-substituted diketopiperazines (DKPs) were synthesized by solid-phase protocols. The introduction of iminodiacetic acid (Ida) and followed another α-amino acid residue as the precursor of DKP framework made the present synthesis to be very facile and efficient.     

New Route for Synthesis of MeO-MOP

The axially chiral monophosphine 2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl (MeO-MOP) is a versatile ligand. We report a shorter (four steps from chiral BINOL), more atom-economical synthetic route to MeO-MOP. (R)-BINOL is transformed into its monomethyl ether by the Mitsunobu reaction, and the latter is reacted with triflic anhydride to give its triflate. The C-P coupling of the triflate and diphenylphosphine oxide catalyzed by palladium give a phosphine oxide, the precursor of (R)-MeO-MOP, which is reduced with trichlorosilane to furnish (R)-MeO-MOP.      

梨小食心虫性信息素的新法合成

梨小食心虫 (Grapholia molesta)是一种世界性果树害虫 ,主要危害梨、桃和苹果等果树 . 1 96 5年Geroge等 [1] 从该雌蛾腹部分离得到其性信息素 . 1 96 9年 Roelofs等 [2 ] 鉴定其结构为 8(Z/E) -十二碳烯 - 1 -醇乙酸酯 (6 ) .国内外对其生物活性进行了大面积田间试验 ,并用于     

Synthesis and Reaction of Vinylic Tellurides

Vinylic tellurides were synthesized by the addition of diorganyl tellurides to acetylenes in the presence of a radical initiator or by visible light irradiation. Vinylic tellurides underwent transmetalation by the reaction with triethylaluminium or diethylzinc to form the corresponding vinylmetal reagents with retention of the double bond configuration. Oxidation of vinylic tellurides formed by carbotelluration reactions followed by pyrolysis gave internal acetylenes in good yields.     

A New Route for the Synthesis of Thymidylate Synthase Inhibitor Raltitrexed

Raltitrexed (8), a new quinazoline-based inhibitor of thymidylate synthase (TS), has been registered widely for the first-line treatment of advanced colorectal cancer. [1,2] As reported in the literature, [3,4] it can be prepared from 2-thiophenecarboxylic acid via 7 steps in 3% overall yield, but n-BuLi and the low temperature at - 78 ℃ was needed for the introduction of 5-carboxyl group into thiophene ring through lithiation of 2-(N-Boc-N-methylamino) thiophene followed by the addition of CO2. Here we wish to report a new route for the synthesis of Raltitrexed which was obtained from 2,5-thiophenedicarboxylic acid via 6 steps in 18.2% overall yield (Scheme 1). The mild conditions utilized in the synthetic route avoid the use of n-BuLi, NaH and the experimental conditions of low temperature at - 78 ℃ and strictly free of water, and are suitable for the large-scale preparation.     

合成4-巯基-1-丁醇的新方法

报道了一种合成4-巯基-1-丁醇（1）的新方法。以1,4-丁二醇为原料,经磺酰化反应及亲核取代反应制得1,总收率达75%,纯度98%（GC）,其结构经¹H NMR和MS（ESI）确证。     

A New Route for the Synthesis of (±)-Seudenol

Seudenol (3-methyl-2-cyclohexen-1-ol) is an aggregation pheromone isolated from female hindguts of the Douglas fir beetle, ^{Dendroctonus pseudotsugae},by Vité^[l]. Sivlerstein reported that the natural seudenol is racemic^[2]. Racemic seudenols have been synthesized by various methods^[3-5], almost all of which have used 3-methyl-2-cyclohexen-1-one (4) as precursor or intermediate, followed by reduction. Among reduction of enone (4), most systems studied to date have focused on selective reduction of α, β-unsaturated ketone to the corrsponding allylic alcohol. But most of the reduction required special and expensive reagent^[3-5]. In this paper,a new convenient material route was reported to synthesize (±)-seudenol. The route is illustrated in the following scheme.     

Hypervalent Iodine in Synthesis XXVI: A Convenient Synthesis of Acetylenic Tellurides

Abstract: Acetylenic tellurides have been prepared by the reaction of sodium arenetellurolates with alkynylphenyliodonium tosylates in DMF.     

Hypervalent Iodine in Synthesis 45: A Simple Method for Stereoselective Synthesis of Vinylic Tellurides

Vinylic tellurides have been prepared stereoselectively by the reaction of sodium tellurolates with vinyl(phenyl)iodonium salts with retention or inversion of the configurations.     

Synthesis of Dialkyl Phosphoroselenocyanatidates and Their Rearrangement to Dialkyl Phosphoroiso-selenocyanatidates

The synthesis of diaryl and dialkyl phosphoroisoseleno-cyanatidates (I) has been described only recently^1,2. However, their isomers, dialkyl or diaryl phosphoro-selenocyanatidates (II) are, to our knowledge, unknown. In our attempts of their synthesis we found that the preparation of II in the way analogous to the synthesis of the corresponding thiocyanatidates ³was not possible due to the inaccessibility of the 0,0-dineopentoxy-oxo-phosphoraneselenenyl chloride (III). Reaction of triethylamminium 0,0-dineopentyl-phosphoroselenoate (IVa) with sulphuryl chloride at -70[ddot]C in CH₂Cl₂ solution led     

一种在堇青石蜂窝陶瓷上合成ZSM-5分子筛的新途径

Cordierite honeycombs are widely used as mono lith reactors in high gas flux circumstances due to their high thermal stability and low-pressure drop,such as catalytic converters in automotive emission control. In recent years, some attempts have been made to support zeolites onto cordierite honey combs[1-4]. In view of the relative complex config uration of the cordierite honeycombs, there have been some difficulties to obtain a zeolite layer with an even and enough thickness on every channel wall by the traditional hydrothermal technique. In the present paper, we for the first time apply vapor phase transport (VPT) technique to the synthesis of ZSM-5 onto cordierite honeycombs. And, to verify the feasibility of this technique, we prepared the Cu/ZSM-5 monolith catalyst by ion exchange, and tested its catalytic performance for NO reduction with C3H8.     

合成磷酰氯二烷基酯的新方法

以亚磷酸三烷基酯为原料,三氯异氰尿酸为氯代试剂,二氯甲烷为溶剂,在室温下合成了磷酰氯二烷基酯,其结构经1H NMR, 31P NMR和GC-MS确证.